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We describe the creation of a solid-state optical sensor that is quick to respond, sensitive, and reliable for detecting and determining Cu(II) ions in both natural and wastewater sources. The solid-state template was prepared with mesoporous silica nanospheres of capacious porosity, high surface area, and uniform surface morphology. N,N'-bis(3-carboxysalcylidene)-4-chloro-1,2-phenylenediamine (CSCPD), a chromoionophoric probe with exclusive ion-selectivity and sensitivity for Cu(II), is created for use in naked-eye colorimetric detection. The mesoporous silica nanospheres (MSNs) template displayed several diffusible sites for the uniform anchoring of the CSCPD probe molecules, which serve as a colorimetric ion sensor for the naked eye. The surface profile and structure of the MSNs and the CSCPD sensor materials are studied using BET/BJH, XPS, FESEM, p-XRD, and HR-TEM analysis. With various concentrations of Cu(II), the CSCPD probe-anchored MSNs material reciprocates a vivid visual colour shift from an initial pale yellow colour to green with a reaction period of around one minute. In addition, the MSNs are simply covered with probe molecules as part of the sensor production process. The certified limits of detection for Cu(II) ions for the proposed CSCPD sensor is 1.57 ppb (2.48 × 10−8 M). The suggested CSCPD sensor is dual-functional in that it may be used as a concentrator to recover ultra-trace quantities of Cu(II) ions as well as an effective ion-sensing device. [ABSTRACT FROM AUTHOR]

Diuretics are drugs that promote the excretion of water and electrolytes in the body and produce diuretic effects. Clinically, they are often used in the treatment of edema caused by various reasons and hypertension. In sports, diuretics are banned by the World Anti-Doping Agency (WADA). Therefore, in order to monitor blood drug concentration, identify drug quality and maintain the fairness of sports competition, accurate, rapid, highly selective and sensitive detection methods are essential. This review provides a comprehensive summary of the pretreatment and detection of diuretics in various samples since 2015. Commonly used techniques to extract diuretics include liquid-liquid extraction, liquid-phase microextraction, solid-phase extraction, solid-phase microextraction, among others. Determination methods include methods based on liquid chromatography, fluorescent spectroscopy, electrochemical sensor method, capillary electrophoresis and so on. The advantages and disadvantages of various pretreatment and analytical techniques are elaborated. In addition, future development prospects of these techniques are discussed. HIGHLIGHTS: Pretreatment and determination methods of diuretics in diverse samples are reviewed. Applications of novel materials and technologies for SPE and sensors are highlighted. Pros and cons of recent pretreatment and analysis techniques used for diuretics are discussed. Applications of high-resolution mass spectrometry are described in detail. [ABSTRACT FROM AUTHOR]

During the COVID-19 process, determination-based analytical chemistry studies have had a major place at every stage. Many analytical techniques have been used in both diagnostic studies and drug analysis. Among these, electrochemical sensors are frequently preferred due to their high sensitivity, selectivity, short analysis time, reliability, ease of sample preparation, and low use of organic solvents. For the determination of drugs used in the SARS-CoV-2, such as favipiravir, molnupiravir, ribavirin, etc., electrochemical (nano)sensors are widely used in both pharmaceutical and biological samples. Diagnosis is the most critical step in the management of the disease, and electrochemical sensor tools are widely preferred for this purpose. Diagnostic electrochemical sensor tools can be biosensor-, nano biosensor-, or MIP-based sensors and utilize a wide variety of analytes such as viral proteins, viral RNA, antibodies, etc. This review overviews the sensor applications in SARS-CoV-2 in terms of diagnosis and determination of drugs by evaluating the most recent studies in the literature. In this way, it is aimed to compile the developments so far by shedding light on the most recent studies and giving ideas to researchers for future studies. [ABSTRACT FROM AUTHOR]

Caste plasticity is an essential trait in social insects, and it facilitates the allocation of individuals in different tasks according to population demands in the colony (e.g. workers can become queens upon loss or death of their "original queen"). The process of caste determination can take place in immature stages (preimaginal) or through adult stages (imaginal). Neotropical social wasp tribe Epiponini has both types of caste determination process and is thus a fascinating group to study caste plasticity. We performed queen removal tests in five Epiponini species with preimaginal and imaginal caste determination to better understand caste plasticity and queen selection processes. Queen absence stimulates the establishment of new reproductive females in Chartergellus and Metapolybia (imaginal), while females in Protopolybia (preimaginal) attempt to lay eggs even in the presence of their "original queen". Contrary to what has been hypothesized, we found that age is not a predictive factor in the female's potential to become a queen. Caste flexibility seems to be a crucial trait which aids Epiponini tropical colonies to survive, as it allows the colony to replace lost workers and queens promptly until a new generation of wasps can emerge. Highlights: Epiponini wasps presented caste flexibility since workers of different ages could replace queens in the case of they lost. [ABSTRACT FROM AUTHOR]

Nowadays, the rapid improvements in the medical and pharmaceutical fields increase the diversity and use of drugs. However, problems such as the use of multiple or combined drugs in the treatment of diseases and insensible use of over-the-counter drugs have caused concerns about the side-effect profiles and therapeutic ranges of drugs and environmental contamination and pollution problems due to pharmaceuticals waste. Therefore, the analysis of drugs in various media such as biological, pharmaceutical, and environmental samples is an important topic of discussion. Electrochemical methods are advantageous for sensor applications due to their easy application, low cost, versatility, high sensitivity, and environmentally-friendliness. Carbon nanomaterials such as diamond-like carbon thin films, carbon nanotubes, carbon nanofibers, graphene oxide, and nanodiamonds are used to enhance the performance of the electrochemical sensors with catalytic effects. To further improve this effect, it is aimed to create hybrid platforms by using different carbon nanomaterials together or with materials such as conductive polymers and ionic liquids. In this review, the most used carbon nanoforms will be evaluated in terms of electrochemical characterizations and physicochemical properties. Furthermore, the effect of hybrid platforms developed in the most recent studies on electrochemical sensors will be examined and evaluated in terms of drug analysis studies in the last five years. [ABSTRACT FROM AUTHOR]

The rapid quantification of toxins in food and beverage products has become a significant issue in overcoming and preventing many life-threatening diseases. Aflatoxin-contaminated food is one of the reasons for primary liver cancer and induces some tumors and cancer types. Advancements in biosensors technology have brought out different analysis methods. Therefore, the sensing performance has been improved for agricultural and beverage industries or food control processes. Nanomaterials are widely used for the enhancement of sensing performance. The enzymes, molecularly imprinted polymers (MIP), antibodies, and aptamers can be used as biorecognition elements. The transducer part of the biosensor can be selected, such as optical, electrochemical, and mass-based. This review explains the classification of major types of aflatoxins, the importance of nanomaterials, electrochemical, optical biosensors, and QCM and their applications for the determination of aflatoxins. [ABSTRACT FROM AUTHOR]

AbstractMolecularly imprinted polymers (MIPs) have become more prevalent in fabricating sensor applications, particularly in medicine, pharmaceuticals, food quality monitoring, and the environment. The ease of their preparation, adaptability of templates, superior affinity and specificity, improved stability, and the possibility for downsizing are only a few benefits of these sensors. Moreover, from a medical perspective, monitoring therapeutic medications and determining pharmaceutical compounds in their pharmaceutical forms and biological systems is very important. Additionally, because medications are hazardous to the environment, effective, quick, and affordable determination in the surrounding environment is of major importance. Concerning a variety of performance criteria, including sensitivity, specificity, low detection limits, and affordability, MIP sensors outperform other published technologies for analyzing pharmaceutical drugs. MIP sensors have, therefore, been widely used as one of the most crucial techniques for analyzing pharmaceuticals. The first part of this review provides a detailed explanation of the many polymerization techniques that were employed to create high-performing MIP sensors. In the subsequent section of the review, the utilization of MIP-based sensors for quantifying the drugs in their pharmaceutical preparation, biological specimens, and environmental samples are covered in depth. Finally, a critical evaluation of the potential future research paths for MIP-based sensors clarifies the use of MIP in pharmaceutical fields. [ABSTRACT FROM AUTHOR]

Haloacetic acids (HAAs) are a class of disinfection by-products (DBPs), widely occurring in drinking water, wastewater and swimming pool water with concentrations at sub-μg/L to mid-μg/L levels. HAAs arose public attention due to their cytotoxicity, genotoxicity and carcinogenicity. Monitoring HAA concentration levels in aqueous environments is required. This review presents an overview of all techniques or methods for sample pretreatment, analysis and removal of HAAs in aqueous environments since 2000. For the pretreatment methods, the commonly used methods are compared and discussed in terms of advantages and drawbacks. Microextraction techniques are preferred as they are efficient, rapid and environment-friendly. Emerging pretreatment methods, such as techniques based on novel materials or liquids, have also been introduced. For the analytical methods, LC and GC coupled with various detectors are frequently used allowing detection at the required low μg/L levels in aquatic environments. The advances in mass spectrometers (MS) and a comparison between their pros and cons are summarized herein. Recent high resolution MS gave give mass accuracy of 0.0001 Da with a resolving power up to 140,000 full width at half maximum height improving feature identifications in nontargeted analyses. For HAA removal methods, advanced oxidation techniques, adsorption and biodegradation were updated, improved and upscaled. Combining two or more removal techniques, the efficiency can reach 99%. Lastly, this review points out critical gaps and proposes future trends. [ABSTRACT FROM AUTHOR]

Coffee is one of the most popular non-alcoholic beverages, consumed as a raw material in different food sectors. The popularity of coffee is induced by its pleasant flavor, taste, and highly nutritious nature. However, the absorption of potentially toxic elements (PTEs) through preharvest, harvesting, and post-harvest stages makes it a potentially rich source. Essential elements are potentially toxic at a higher concentration than required for the human body to work. PTEs intake through food systems may lead to health risks, including mutagenicity, teratogenicity, carcinogenicity, and embryotoxic effects. Different analytical techniques such as spectroscopy, electromigration, and electrochemical. are used for PTEs content determination of coffee. Considering the importance of PTEs in human health and the worldwide popularity of coffee, their monitoring of coffee is crucial. Therefore, this study is aimed to investigate the classification, prevalence, and determination techniques of PTEs in different coffee types. [ABSTRACT FROM AUTHOR]

Anthropogenic contaminants, as pesticides, polycyclic aromatic hydrocarbons (PAHs) and monochloropropanediols (MCPDs), have become important to be controlled in edible oils, since their regular occurrence. In fact, alerts from the Rapid Alert System for Food and Feed (RASFF) in oils normally include these compounds. From a critical point of view, tools used to control these compounds in the last 5 years will be discussed, including sample preparation, analysis and current regulations. Extraction and analysis methods will be discussed next, being liquid-liquid extraction (LLE) and QuEChERS, with or without clean-up step, as well as chromatographic methods coupled to different analyzers (mainly mass spectrometry), the most commonly used for extraction and analysis respectively. Occurrence in samples will also be reviewed and compared with the legal maximum residue limits (MRLs), observing that 4%, 20% and 60% of the analyzed samples exceed the legal limits for pesticides, MCPDs and PAHs respectively. [ABSTRACT FROM AUTHOR]

Preparing samples for analyses is perhaps the most important part to analyses. The varied functional groups present on the surface of biopolymers bestow them appropriate adsorption properties. Properties like biocompatibility, biodegradability, presence of different surface functional group, high porosity, considerable absorption capacity for water, the potential for modification, etc. turn biopolymers to promising candidates for varied applications. In addition, one of the most important parts of determination of an analyte in a matrix is sample preparation step and the efficiency of this step in solid phase extraction methods is largely dependent on the type of adsorbent used. Due to the unique properties of biopolymers they are considered an appropriate choice for using as sorbent in sample preparation methods that use from a solid adsorbent. Many review articles have been published on the application of diverse adsorbents in sample preparation methods, however despite the numerous advantages of biopolymers mentioned; review articles in this field are very few. Thus, in this paper we review the reports in different areas of sample preparation that use polysaccharides-based biopolymers as sorbents for extraction and determination of diverse organic and inorganic analytes. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) are fluorocarbon compounds in which hydrogen atoms have been partly or entirely replaced by fluorine. They have a very wide range of applications, while they are persistent in the environment and exhibit bioaccumulative and toxic properties. Neither chemical nor biological mechanisms can decompose PFAS due to their strong C-F bonds. PFAS have shown adverse effects on various organisms, even at trace levels. Accordingly, highly sensitive and selective analytical methods are required for their tracing in biological and environmental matrices. The physicochemical properties of PFAS like surfactant characteristics and high-water solubility are unique and different from other known pollutants. Accordingly, the number of articles on the analysis of PFAS is less than the other well-known contaminants. The routine PFAS sample preparation methods (like solvent extraction) coupled with chromatographic systems, face challenges such as high limits of detection, need for laborious derivatization, limited selectivity, and expensive instrumentation. Recent efforts to address these limitations have aroused considerable attention to the development of microextraction techniques, which are consistent with the principles of green chemistry and can be made easily portable and automated. Moreover, these methods have shown enough sensitivity and selectivity for the analysis of different analytes (including PFAS) in a wide range of samples with different matrices. This research aims to review the microextraction methods and detection techniques, applied for the sample pretreatment of PFAS in various matrices, along with a critical discussion of the challenges and potential future trends. [ABSTRACT FROM AUTHOR]

Though the knowledge on delta 5-unsaturated-polymethylene-interrupted fatty acids (Δ5-UPIFAs) is being updated, the issue of their integration still exists within the field. Thus, this review systematically summarizes the sources, biosynthesis and metabolism, analytical methods, preparation, and health-promoting roles of Δ5-UPIFAs. In plants, the content of Δ5-UPIFAs is higher, which is an ideal source. In animals, although the content of Δ5-UPIFAs is not high, there are many species, which is the possible source of some special Δ5-UPIFAs. At present, although the extraction of Δ5-UPIFAs is mainly from plants, the fermentation by organisms, especially for genetically modified microorganisms engineering maybe be a substitue of pepration of Δ5-UPIFAs. Δ5-UPIFAs have been proved to possess multi-beneficial effects, such as lipid lowering, anti-inflammation and so on, so it has a certain potential application value. However, related knowledge of the underlying molecular mechanisms regarding Δ5-UPIFAs limited, and how Δ5-UPIFAs work is not clear. Further clinical and human studies about Δ5-UPIFAs are also needed. Studies on tapping new resources, developing structured lipide rich in Δ5-UPIFA and enhancing delivery were quite deficient. This review emphasizes the further directions on Δ5-UPIFAs with scientific suggestions to pay more attention to the applications of Δ5-UPIFAs in food, pharmaceutical and cosmetic industries. [ABSTRACT FROM AUTHOR]

Tl(III) was extracted and preconcentrated using cloud point extraction (CPE) for its determination in water samples using flame atomic absorption spectrometry (FAAS). The CPE procedure was performed using a non-ionic surfactant octylphenoxypolyethoxyethanol (Triton X-114) as an extractant at room temperature in the presence Br− or I−. Tl(I) was oxidized in presence of bromine water to T(III) to form Tl(Br)3 complex which then was extracted into the surfactant-rich phase. The factors influencing the CPE such as sample pH, concentrations of bromide and iodide ions and Triton X-114 were studied. After optimisation of CPE conditions, the preconcentration factors were found 74 for Br2 and 68 for KI, the limits of detection (3 s) were 5.7 and 8 ng mL−1 for Br2 and KI, respectively. The relative standard deviation (RSD) was 3.7% for Br2 and 2.6% for KI. The results showed that the proposed method was free from interference. The CPE method was successfully used for Tl(III) determination in real samples. [ABSTRACT FROM AUTHOR]

Sulforaphene (SRP) is the main isothiocyanate produced by myrosinase hydrolysis of glucoraphanin from Cruciferae plants. This review discusses the latest results on the formation, content, and stability of SRP. SRP is unstable when the solution system contains amino-acids or solvents with hydroxyl groups. Different strategies to inhibit the SRP degradation and increase the hydrolysis yield have been discussed in detail. The separation, purification and SRP determination methods are described in the review. SRP has herbicidal, antimicrobial, antimutagenic, and metabolic activities, and especially an anticancer activity. These findings indicate that SRP can be considered as a prospective therapeutic agent for major human diseases. However, for possible medicinal SRP applications, there is an urgent demand for development of new strategies for purification methods and chemical synthesis maintaining SRP stability. In addition the precise mechanism of action of SRP should be thoroughly clarified. [ABSTRACT FROM AUTHOR]

Phenolic compounds can cause health problems in humans through the food chain. Considering that fish play an important role in human diets, we established a rapid, simple and high-throughput method for the determination of 18 phenolic compounds in fish based on a modified QuEChERS sample preparation method combined with GC-MS. The average recovery of the 18 phenolic compounds was 81.3–116% at 3 spiked levels, and the relative standard deviations, RSDr and RSDwR, were in the range of 1.1–11.3% and 1.5–12.2%, respectively. The limit of detection was 2.0–10.1 μg/kg. Satisfactory linear relationships (R2 > 0.998) were observed for the phenolic compounds in their corresponding concentration ranges. Moreover, the established method exhibited a high sensitivity, good stability, and reliability. The development of this method has an important theoretical and practical significance for establishing standards and to control the residue levels of phenolic compounds in fish. [ABSTRACT FROM AUTHOR]

Drug residues in water represent one of the most serious environmental problems because of their high toxicity to the biological system. Thus, this study reports a low-cost strategy for fast and precise analysis of β- blocker timolol maleate (TM) using differential pulse anodic stripping voltammetry (DP ASV) at a bare glassy carbon electrode (GCE). At the optimised solution pH 7.2 and other analytical parameters (accumulation time, deposition potential, scan rate, and pulse amplitude), a well-defined oxidation peak was observed at 0.85 V vs Ag/AgCl electrode. The linear calibration range for TM at 0.85 V vs. Ag/AgCl electrode was found to be 5.0 × 10−7 – 1.3 × 10−4 mol L−1 (0.21–56.2 μg mL−1) (R2 = 0.9947) with lower limits of detection (LOD) and quantitation (LOQ) of 2.7 × 10−7 (0.12) and 8.99 × 10−7 mol L−1 (0.39 μg mL−1), respectively. The developed assay was satisfactorily applied for trace determination of TM residues in biological fluids (urine), environmental water samples and eye drop with good recoveries (90.5 ± 0.66–106 ± 0.66%), demonstrating good accuracy and applicability of the proposed method as an effective and reliable electrochemical sensor for analysis of TM in complex matrices. Common organic and inorganic compounds did not interfere with TM in its determination. The established strategy was validated using the official HPLC method. Analysis results obtained by the present method were comparable to those obtained using the official method; indicating that the proposed method could be used as an alternative method for the routine quality control of the drug in complex matrices. Chromatographic methods are still more precise, while electrochemical sensors are promising for the analyte determination as they have reduced analytical time, low cost and reproducible. The proposed sensor also demonstrated excellent precision, selectivity, and reproducibility for TM determination. [ABSTRACT FROM AUTHOR]

Phthalocyanines are aromatic or macrocyclic organic compounds and attract great attention due to their numerous properties. They have many high-tech applications in different areas of the industry such as dyestuffs, thermal printing screens, photovoltaic solar cells, membrane catalytic reactors, semiconductor materials and gas sensors. In the last decade, electrochemical sensor studies have accelerated with the catalytic lighting. It plays a dominant role in the development and implementation of new generation sensors. The aim of this study is to review the electrochemical methods based on electrode modification with phthalocyanines and to shed light on new application areas of phthalocyanines. The focal point was based on the sensor applications of phthalocyanines in the determination of drugs, pesticides, organic materials and metals etc. by electrochemical methods. Experimental conditions and some validation parameters of the sensor applications such as metal phthalocyanine types, indicator electrodes, selectivity, working ranges, detection limits, and analytical applications were discussed. Consequently, this is the first review dealing with the applications of phthalocyanines in electrochemical sensors for the sensitive determination of analytes in a variety of matrices. [ABSTRACT FROM AUTHOR]

In this work, we developed a simple spectrophotometric strategy for BrO3− ions determination as a major water disinfection constituents in the mice's liver tissues by using pararosaniline (PRA). Mice were divided into seven main groups (6 doses): lowest dose KBrO3 (G1 0.01 mg L−1, G2 0.025 mg L−1 and G3 0.1 mg L−1), highest dose KBrO3 (G4 1 mg L−1, G5 10 mg·L−1 and G6 30 mg L−1) and control. All these groups maintained a dose-specific feeding for one month, just before the bromate assessment in mice's liver samples. The results revealed that groups of exposure to lower doses of drinking water did not detect the presence of BrO3− accumulated in the liver tissue during the study period (1–2 months). While, the BrO3− was detected in higher dosages for samples analyzed in first, second, third, fourth and fifth weeks (W1, W2, W3, W4, and W5). These results confirmed that the higher BrO3− dosages (1, 10, and 30 mg L−1) were fatal if introduced in drinking water and could accumulate in the liver tissues both for mice and for human. Detection the accuracy of the method for recovery of bromate ions in liver samples (N = 5) was found to be more than 95%. Relative standard deviations (RSDs) were found to be less than 2.0% confirming the reproducibility of the assay technique. [ABSTRACT FROM AUTHOR]

With the outbreak caused by the severe acute respiratory syndrome coronavirus (COVID-19), people's health and existing economies on a global scale are seriously threatened. Currently, most of the countries all over the world are studying extensively to better understand the antimalarial chloroquine (CQ) and hydroxychloroquine (HCQ) for therapeutic purposes due to the COVID-19 outbreak. However, CQ and HCQ can have serious side effects, from psychiatric effects to sudden death. Therefore, a faster and more effective detection method is needed to monitor drug concentrations. In this review, a large study was conducted on the detection techniques and quantitative determination methods of CQ and its related metabolites. In this review, chromatography, electrophoresis, electroanalytical, spectroscopic, and immunological methods for CQ and related metabolites are discussed extensively. It is hoped that a better understanding of the CQ used for therapeutic purposes in the COVID-19 outbreak will be provided. [ABSTRACT FROM AUTHOR]

Ambrisentan is an oral endothelin-receptor antagonist (ERA). However, there is no report on the interaction between ambrisentan and shikonin. To investigate the effect of shikonin on ambrisentan metabolism in vivo and in vitro. This study developed an ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for simultaneous determination of ambrisentan and (S)-4-hydroxymethyl ambrisentan in rat plasma. Twelve male Sprague-Dawley (SD) rats were divided into two groups (n = 6): the control group and shikonin (20 mg/kg) group. The pharmacokinetics of ambrisentan (2.5 mg/kg) were investigated after 30 min. Additionally, human and rat liver microsomes were used to investigate the herb-drug interaction. The UPLC-MS/MS method was shown to be accurate, precise and reliable, and was successfully applied to the herb-drug interaction study of ambrisentan with shikonin. When co-administrated with 20 mg/kg shikonin, the Cmax and AUC(0–∞) of ambrisentan were significantly increased by 44.96 and 16.65%, respectively (p < 0.05). In addition, there were modest decreases in (S)-4-hydroxymethyl ambrisentan Cmax and AUC(0–∞) in the presence of shikonin (p < 0.05), which indicated that these results were in accordance with the inhibition of shikonin on ambrisentan metabolism. Moreover, enzyme kinetic study indicated that shikonin had an inhibitory effect on human and rat microsomes where the IC50 values of shikonin were 5.865 and 6.358 μM, respectively. Our study indicated that shikonin could inhibit ambrisentan metabolism. Further studies need to be carried out to verify whether similar interaction truly apply in humans and whether this interaction has clinical significance. [ABSTRACT FROM AUTHOR]

Fatty acids (FAs) are a class of lipids found in everyday foods that are closely related to human health. These chemicals are involved in many physiological functions. The establishment of methods for the analysis of FAs in different foods is necessary. In this review, an updated overview of the pretreatment and analysis methods that have been reported since 2012 is given. Sample preparation methods involve extraction, fractionation and derivatization, while analysis methods involve chromatographic, spectral, and electrophoretic methods, as well as several other methods. Different pretreatment and determination methods are discussed. [ABSTRACT FROM AUTHOR]

The objective of this study was to synthesize information on the analytics, using two separation techniques, and the application of electrostatically stabilized silanate derivatives. They are biologically active, water-soluble, hydrolytically stable and biodegradable. Some of these compounds are used as plant growth regulators, while others, with higher molecular mass and lower electrophoretic mobility, are used in the form of terminating electrolytes in isotachophoresis, which is regarded as one of the green chemistry techniques. Two compounds were successfully used in the form of terminating electrolyte solutions, i.e. 4,4'-bis{1-(perhydroazepiniomethyl)[spirobi(1-sila-2,5-dioxacyclopentane-3-on)]at}, and 4,4'-bis{1-[(N,N-dimethyl)aminiomethyl]spirobi(1-sila-2,5-dioxacyclopentane-3-on)at} to isolate organic ionic substances with high molecular mass, e.g. derivatives of quinoline, stilbene and electrostatically stabilized silanates (ES-silanates). Establishing the best conditions for the analysis of these derivatives extends the possibilities of conducting research on their biological activity and miscellaneous applications. Furthermore, the terminating electrolytes used in the form of solutions of electrostatically stabilized silanates allow the analysis of both cationic and anionic forms. [ABSTRACT FROM AUTHOR]

Gamma-tocopherol (γ-T), the major form of vitamin E in many plant seeds and products derived from them, has been attracting increasing attention because of its health-promoting roles. However, the underlying molecular mechanisms are still unclear, to some degree. Furthermore, its dimmers and quinones are expected to be potential nutritious and pharmaceutical agents, however, the knowledge about these dimmers (γ-TBD and γ-TED) and quinones (para- and ortho-quinones) is relatively limited. Thus, a comprehensive summary of the history, chemical structure, source, determination, absorption, transport, and metabolism of its dimmers and quinones compared to γ-T has been reviewed. In addition, the antioxidant activity (AOA) and non-AOA activity of these substances are highlighted. It is suggested that more special attention be paid to the dimmers and quinones for better understanding and further applications. [ABSTRACT FROM AUTHOR]

ZnO nanocomposite was synthesised by immobilisation of ZnO nanoparticles on sodium bentonite surface and the prepared nanocomposite (nZnO-Bn) was used to remove, preconcentrate and to determine spectrophotometrically trace amounts of an anionic dye (bromocresol purple, BCP) in tap, Nile, sea and industrial water samples. nZnO-Bn was characterised via X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and Brunauer–Emmett–Teller (BET) technique. Factors effect on BCP removal as shaking time, solution pH, BCP initial concentration and temperature was explored in a batch mode. In addition, sorption kinetics, isotherms, thermodynamics, and reusability were studied. Pseudo-second-order kinetic model explained well the experimental results. Freundlich isotherm has been found to have a high correlation coefficient. The sorbed BCP was successfully desorbed using acetone and determined spectrophotometrically. The nZnO-Bn nanocomposite could be regenerated efficiently and recycled up to the fifth cycle with a removal efficiency of more than 83%. The proposed method for BCP determination provided a wide linear range from 15.63 to 2000 μg L−1 of BCP. Moreover, the recoveries of BCP from spiked water samples ranged from 90.34% to 100.12%, indicating the suitability of nZnO-Bn as an efficient sorbent for the removal and determination of BCP in real samples. [ABSTRACT FROM AUTHOR]

Each year about 250 million people around the world are infected with parasites from the Plasmodium group causing malaria. Although more than 50 antimalarials are currently being tested, cinchona tree alkaloids in the form of quinoline derivatives are still used to treat the disease. The objective of this work was to develop and apply a novel method for separation and determination of six biologically active alkaloids using isotachophoresis. The following derivatives were involved in the study: quinine, quinidine, cinchonine, cinchonidine, acetylcinchonine, and acetylquinidine. Successful application of isotachophoresis for the separation of these diastereoisomers required a new terminating electrolyte. The developed method allows for separation of the above-mentioned alkaloids in less than 33 minutes. Linear regression coefficients were high and ranged from 0.9995 to 0.9999. Relative standard deviation did not exceed 5%, and the standard measurement uncertainty was below 3 μgL−1. The new method was then successfully used to determine quinine content in selected products. [ABSTRACT FROM AUTHOR]

In this work, a simple, sensitive and rapid method for the determination of trace amounts of catechol (CT) in aqueous media has been suggested. For this purpose, poly(1H-1,2,4-triazole-3-thiol) film was electrochemically deposited successfully at the gold electrode (Au/T3T). The electrochemical behaviour of CT was studied on the Au/T3T electrode by the cyclic voltammetry and differential pulse voltammetry techniques. The anodic peak current value and the concentration of CT showed a good linear relationship in the range of 0.015–2.8 µM. The limit of detection was found as 1.88 nM (S/N = 3). Besides, the reproducibility, repeatability, stability and interference measurements were also assayed. This sensor was applied successfully for the detection of CT in synthetic and real samples. [ABSTRACT FROM AUTHOR]

The purpose of this study was to test alternative models of sport commitment with a youth sport sample. Competitive female gymnasts (N = 792; Levels 4–10), ages 8–19 years (M = 11.68, SD = 2.33), completed measures designed to assess the determinants of commitment. Data were analysed via path analysis models in the lavaan package in R. Three separate models were fitted: (a) direct effects model, (b) a mediational model testing the indirect effects of the predictors via enjoyment, and (c) direct and indirect effects of the predictors on sport commitment. Of the models tested, the direct and indirect effects model yielded the best fit of the data (RMSE =.03 90% CI [.000,.057], TLI =.989, CFI =.997, NFI =.989; 67% of the variance in commitment explained). The model revealed that enjoyment, involvement opportunities, investments, and attractive alternatives had a direct effect on commitment. With regard to the indirect effects of the determinants on commitment via enjoyment, attractive alternatives, involvement opportunities, investments, costs, parent and best friend social constraints, and coach and teammate social support had direct effects on enjoyment, which predicted the level of gymnastics commitment. Additionally, some differences emerged in the salient predictors of commitment for high versus low level competitors. The role of enjoyment within commitment is complex depending on competitive level, and future research should consider alternative models when examining the role of social influence on sport commitment. [ABSTRACT FROM AUTHOR]

A green and simple deep eutectic solvent-based ultrasound-assisted liquid phase microextraction method has been developed for the preconcentration of copper as 2-(5-bromo-2-pyridylazo)-5-(diethylamino) phenol chelates. The effects of pH, ligand concentration, DES volume, sample volume, and tetrahydrofuran volume were investigated. Analytical performance parameters like limit of detection, limit of quantification, preconcentration factor, and relative standard deviation were determined as 6.6 μg L−1, 21.8 μg L−1, 15, and <5%, respectively. Validation of the developed method was checked by the analysis of certificated reference materials. The procedure was successfully applied to determination of copper in olive oil and water samples. [ABSTRACT FROM AUTHOR]

The paper collates and summarizes information on stilbene derivatives, i.e. (E)-azastilbenes, taking into account the new possibilities of their applications, inter alia, in the natural environment. (E)-azastilbenes are biologically active, which is of great importance to humans and the whole ecosystem. As evidenced by a number of studies, they show fungistatic, fungitoxic and, depending on the concentration, estrogenic properties. Due to their properties, (E)-azastilbenes are still of great interest to researchers, who have high hopes for their pharmacological use or the possibility of using them as antiseptics, disinfectants, or preservatives in various products, including the environmental ones. Because of the difficulties with their determination, the study assumes optimal conditions of (E)-azastilbenes extraction from environmental samples and the technique of isotachophoresis is employed for the first time in this type of analysis. The highest recovery values ranging from 83 to 97% were obtained on the aryl extraction columns. The range of linearity of the developed method on the naphthylpropyl column ranged from 5 to 300 µg/mL. [ABSTRACT FROM AUTHOR]

The present article argues that the concept of predestination does not on the whole lend itself to Qumran studies. Unlike the writings of Augustine and Calvin, the scrolls contain nothing like a doctrine of predestination. The article reviews several texts from 1QS, 1QH, and CD, generally understood to reflect predestination, and suggests other ways of describing and interpreting the material. [ABSTRACT FROM AUTHOR]

ϒ-aminobutyric acid (GABA) is a ubiquitous non-proteinaceous amino acid with many health-promoting benefits. GABA in some fruits has been reported previously. However, there have been no previous reports of GABA in jujube fruit. Therefore, the purpose of this study was to investigate the content of GABA in different jujube cultivars and the effect of harvest, drying and storage on GABA of jujube fruit. In six jujube cultivars studied, Z. Jujuba cv. Junzao had the highest GABA content of 333.37 µg.g−1 DW, while Z. Jujuba cv. Dongzao had the lowest GABA content of 150.31 µg.g−1 DW. The GABA content of jujube fruit (Z. jujuba Mill.cv.Junzao) was nearly doubled by delaying harvest time probably due to cold stress, while it was significantly decreased by the treatment of drying and storage. Interestingly, these findings suggest that normal consumption amount of jujube fruit might contain sufficient GABA to produce the effects of improving sleep and lowering blood pressure. [ABSTRACT FROM AUTHOR]

Malachite green (MG) has been widely used in the aquaculture industry as a fungicide and parasiticide because of its high efficiency and low cost, and it is commonly found in aquatic products and environmental water. However, MG and its primary metabolite, leuco-malachite green (LMG), are also toxic inorganic contaminants that are hazardous to the health of humans and other organisms. A variety of methods have been proposed in recent years for detecting and monitoring MG and LMG. This article was compiled as a general review of the methods proposed for MG and LMG detection, and several important detection parameters, such as the limit of detection, recovery and relative standard deviation, were tabulated. The analytical methods for the determination of MG and LMG in various matrices include high-performance liquid chromatography separation-based methods, liquid chromatography tandem mass spectrometry, surface-enhanced Raman spectroscopy, electrochemical methods, immunological assays, spectrophotometry and fluorescent methods which were described in detail in this article. In addition, some sample preparation techniques were also described. This review can provide expert guidance to the reader on the advantages, disadvantages and applicability of the different methodologies. This review also discussed challenges and several perspectives on the future trends in the determination of MG and LMG. [ABSTRACT FROM AUTHOR]

A practical multi-residue method based on ultra-performance liquid chromatography/tandem mass spectrometry was developed for the simultaneous determination of 23 perfluorinated alkylated substances (PFASs) in water and suspended particles. Suspended particle samples were extracted with 1% formic acid-acetonitrile and cleaned by matrix solid phase dispersion extraction using a C18 sorbent and graphitized carbon black. Water samples were filtered through 0.7-μm glass fiber membranes and enriched utilizing weak anion exchange cartridges. The eluent was dried under a gentle stream of N2 at 45°C and suspended in 1 mL acetonitrile-5 mM ammonium acetate (1:1, vol:vol). Gradient elution for chromatographic separation utilized acetonitrile and 5 mM ammonium acetate as mobile phases on a reverse phase C18 column. The compounds were quantified using an internal standard method in multiple reaction-monitoring mode. Limits of detection and quantitation of the 23 PFAS test compounds in water samples were 0.5-10 ng L−1 and 2-20 ng L-1, respectively. Recoveries at three fortified levels of 20, 50, and 200 ng L-1 ranged from 68.5% to 118% with relative standard deviations below 9.6%. We used this method to determine PFAS levels in real water and suspended particle samples and found high sensitivity and good reproducibility. [ABSTRACT FROM AUTHOR]

Gangliosides (GGs) are important bioactive compounds that offer beneficial anti-infective, anti-inflammatory, and neuronal development effects. The present work reviews the techniques used to determine the GG content in human milk and infant formula. In the case of conventional techniques (thin-layer chromatography (TLC) and spectroscopy), extraction and purification steps are more laborious than for the current techniques (liquid chromatography-mass spectrometry (LC-MS)). The new methodologies allow the identification of the ceramide and oligosaccharide forming the GGs, which is of interest considering their structural differences among human milk and infant formula. This information could be used to incorporate GGs into infant formula in such a way as to more closely resemble human milk regarding total contents and profile. [ABSTRACT FROM AUTHOR]

In scholarship on intellectual property (‘IP’), nonconsequentialist justifications for IP rights seem to suffer from one of two flaws. To some, such justifications seem indeterminate; they seem not to offer concrete guidance about how rights should be structured in practice. To others, such justifications seem dogmatic; they seem to mandate certain conclusions without letting decision makers consider the relevant context or consequences of different proposals to regulate IP. Both impressions neglect an important dimension of reasoning about rights—practical reason. In perfectionist theories of law, ‘practical reason’ describes the principles by which general justifications for rights are implemented in specific decisions in politics and ethics. This article introduces practical reason to IP scholarship, and it shows how practical reason facilitates reasoning about the design of different legal IP rights. The article illustrates with patent’s novelty requirement, copyright’s originality requirement, copyright’s idea-expression distinction, and the duration limits for various forms of intellectual property. [ABSTRACT FROM AUTHOR]

The purpose of this study was to validate a rapid, simple and accurate method using ultra-performance liquid chromatography (UPLC) for the simultaneous determination of 26 anti-diabetic compounds in illegally adulterated dietary supplements. The method was validated for specificity, linearity, limit of detection, limit of quantitation, precision, accuracy, recovery and stability. All compounds were separated with a resolution of over 1.5. The limits of detection and quantitation were 0.10-1.70 and 0.30-5.10 µg g-1 in a solid sample, respectively; the corresponding values were 0.10-1.25 and 0.30-3.75 µg ml-1 in a liquid sample. The correlation coefficient was > 0.99, precisions were 0.11-3.30% (intra-day) and 0.05-6.15% (inter-day), and accuracies were 83-108% (intra-day) and 85-109% (inter-day). The recoveries were measured with six dosage forms, and the results were acceptable as 87-117% with relative standard deviations ≤ 6.44%. The relative standard deviations of stability were ≤ 3.40% and the standard solution was stable for 48 h. Ninety-six samples were obtained from on/off-line markets and were analysed using the developed method. Among these samples, pioglitazone and glibenclamide were found in seven samples and the concentrations of each compound were 0.15% and 0.26-0.51%, respectively. With the increasing adulteration of dietary supplements with anti-diabetic drugs, this method may be helpful to protect public health and safety. [ABSTRACT FROM AUTHOR]

A hybrid linear ion trap-quadrupole-Orbitrap high-resolution mass spectrometry (LTQ-Orbitrap-HRMS) was used to qualitatively and quantitatively analyse the myriocin inIsaria cicadaeand its allies. The samples were prepared with 95% methanol for 30 min by ultrasonic-assisted extraction. The target compound was purified by ODS solid-phase extraction (SPE) column. The enriched samples were identified by mass spectrometry. The results showed that the contents of myriocin in both wild and artificialIsaria cicadaewere below the detection limit, while a strain ofOphiocordyceps longissimaandCordyceps cicadaeShing (Dujiaolong), both closely related to theIsaria cicadae, and its asexual mycelia are rich in myriocin. It suggests that it may be wrong to considerC. cicadaeasI. cicadae’s teleomorph in Genbank or Mycobank in many published reports based on chemical classification, and the species rich in myriocin is probably notIsaria cicadae. [ABSTRACT FROM PUBLISHER]

Ultra-performance liquid chromatography coupled with electrospray ionization tandem quadrupole time-of-flight mass spectrometry (UHPLC−Q-TOF-MS) and HPLC-DAD with an ultrasonic extraction method was developed for qualitative and quantitative compositions and contents in black soybean sprouts. Operational conditions of ultrasonic extraction were optimized by single-factor experiment. Phytochemical compositions of black soybean sprouts were identified by UHPLC−Q-TOF-MS in positive ion mode. A total of 23 compounds were tentatively characterized and identified by means of accurate mass and characteristic fragment ions. Among of them, the six isoflavones in different germinated black soybean sprouts were further quantified by HPLC-DAD. The results indicated that the calibration curves showed good linearity (r2 > 0.9994). The intra-day and inter-day precision variations were less than 1.65% and 1.73%, respectively. The recoveries were in the range of 94.95-106.45%. The results indicated that the maximum amounts of isoflavones were produced on the fourth to fifth day germinated black soybean sprouts. [ABSTRACT FROM AUTHOR]

The aim of this study was to test the applicability of bioelectrical measurements and a needle-type multi-electrode array in evaluating salt and moisture content of structurally heterogeneous food samples, such as fish. Impedance measurements were performed at different frequencies in order to find the most appropriate range, where impedance module and/or phase angle are the most sensitive to salt and moisture content. The salt, moisture, and water phase salt (WPS) of the salted rainbow trout samples were successfully evaluated by the impedance module measured at 50 kHz (AdR2 > 0.85). Due to rapid and non-destructive analysis coupled with low cost device design, this method for determination of salt and/or moisture has potential as the quality control technique for the fish industry. [ABSTRACT FROM AUTHOR]

In this study, a novel method named high-speed homogenization coupled with ultrasound-assisted extraction (HSH-UAE) followed by high-performance liquid chromatography (HPLC) was employed and investigated for the extraction and determination of main flavonoids rutin, quercetin-3-O-glucoside, quercetin, kaempferol and isorhamnetin fromHippophae rhamnoidesL. by-products. Optimal conditions for HSH-UAE, proposed by the single factor and the Box–Behnken design (BBD) tests coupled with response surface methodology (RSM), were 68% ethanol concentration, ultrasonic power 250 W, homogenate speed 9000 rpm, liquid/solid ratio 22 mL/g and extraction time 12 min. The extraction yields of five main flavonoids were significantly improved by HSH-UAE than UAE and high-speed homogenization-assisted extraction (HSHAE). Furthermore, the antioxidant activity of HSH-UAE extracts was assessed by 1,1-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing/antioxidant power (FRAP) assays with IC50value of 0.091 mg/mL and 2.837 mmol FeSO4/g DW. Good linear ranges were obtained for five main flavonoids in the range of 2.5–500 μg/mL with the coefficient higher than 0.99. The recoveries of the five flavonoids were in the range of 97.87–99.26%. The limit of detection (LOD) and the limit of quantification (LOQ) for the main flavonoids were within the ranges of 0.28–0.46 and 0.89–1.74 μg/mL, respectively. The present results showed that the proposed method HSH-UAE could be developed as a fast and efficient method for extracting the active ingredients from medical edible plant materials for potential application. [ABSTRACT FROM PUBLISHER]

The organic olives from Çine-Aydın (Turkey) were washed with tap or ozonated water for 2 and 5 min, respectively, and pressed to olive oil. The effects of wash treatments on fatty acid composition and several quality parameters of the oils were determined. The maximum values after 2-min ozonated water washes were 9.58 meqO2/kg, 0.73%, 2.44 and 0.16 for peroxide, free acid, K232and K270values, respectively, which were under the standard limits for extra-virgin olive oil. Five min of ozonated water washes also yielded acceptable results, except for a slight excess on K232value. Ozonated water washes had almost no effect on fatty acid composition. [ABSTRACT FROM AUTHOR]

Gentiana rigescensis a famous herbal medicine in China for treatment of convulsion, rheumatism, and jaundice. Here, the infrared determination of gentiopicroside, swertiamarin, sweroside, and loganic acid inG. rigescensfrom different areas and varieties was presented for the first time. Reference information for the iridoids were obtained by high-performance liquid chromatography. Partial least squares was used to characterize the relationship between spectra matrix and concentration vector for the determination of the analytes. For determination of gentiopicroside, the appropriate performance of partial least squares model was acquired with coefficient of determination of calibration and coefficient of determination of prediction values of 0.965 and 0.868. The root mean square error of estimation (RMSEE), root mean square error of cross validation (RMSECV), root mean square error of prediction (RMSEP), and residual predictive deviation (RPD) values were 2.612, 5.292, 5.239 mg g−1, and 2.701, respectively, based on the first derivative and multiplicative scatter correction. For determination of the total iridoids, the best results were obtained using the coefficient of determination of calibration and coefficient of determination of prediction of 0.943 and 0.834, RMSEE, RMSECV, RMSEP and RPD of 3.896, 7.536, 6.543 mg g−1and 2.438, respectively, based on the first derivative. Both models were reliable and robust. The results demonstrated that infrared spectroscopy provided a rapid, low-cost tool to monitor the quality ofG. rigescensby the determination of the iridoids. [ABSTRACT FROM PUBLISHER]

Aflatoxins can cause damage to the health of humans and animals. Several institutions around the world have established regulations to limit the levels of aflatoxins in food, and numerous analytical methods have been extensively developed for aflatoxin determination. This review covers the currently used analytical methods for the determination of aflatoxins in different food matrices, which includes sampling and sample preparation, sample pretreatment methods including extraction methods and purification methods of aflatoxin extracts, separation and determination methods. Validation for analysis of aflatoxins and safety considerations and precautions when doing the experiments are also discussed. [ABSTRACT FROM PUBLISHER]

A facile route for producing reduced graphene oxide (RGO)-loaded Au nanoparticles based on ionic liquids (IL) has been proposed, in which the as-prepared RGO can be dispersed stably in water. With the assistance of IL, Au nanoparticles were uniformly and densely absorbed on the surfaces of the IL functionalised reduced graphene oxide (IRGO), forming a new composite of IRGO/Au with high dispersibility. This IRGO/Au composite enhanced its electrochemical signal obviously in the measurement of allura red in foods and exhibited a wider linear response ranging from 0.297 (0.0006 μmol L−1) to 99.3 μg L−1(0.2 μmol L−1) with lower detection limit of 0.213 μg L−1(0.00043 μmol L−1) at a signal-to-noise ratio of 3. To further study the practical applicability of the proposed sensor, the modified electrode was successfully applied to detect allura red in five kinds of common foods and the assay results were in a good agreement with the reference values detected by HPLC. [ABSTRACT FROM PUBLISHER]

The recent debate on cognitive phenomenology has largely focused on phenomenal aspects connected to the content of thoughts. By contrasts, aspects pertaining to their attitude have often been neglected, despite the fact that they are distinctive of the mental kind of thought concerned and, moreover, also present in experiences and thus less contentious than purely cognitive aspects. My main goal is to identify two central and closely related aspects of attitude that are phenomenologically salient and shared by thoughts with experiences, namely the rational role that they play in our mental lives and their determination by factors external to them, such as external objects or reasons. In particular, I aim to defend Phenomenal Rationalism about judgemental thoughts and perceptual experiences: the view that their phenomenal character reflects their rational role, that is, their capacity to provide and/or respond to reasons. I conclude with some remarks about how this view may be extended to other kinds of thought and experience; and about how the phenomenological salience of the specific rational role of individual judgemental thoughts may in fact be used to formulate also an argument for the phenomenological salience of their particular propositional contents. [ABSTRACT FROM AUTHOR]

Zanthoxylum bungeanum, also called the Szechuan pepper, is a pungent-flavored spice. Together with the chili pepper, it constitutes the typical flavor of famous Chinese Szechuan cuisine. With the worldwide popularity of Sichuan cuisine and pungent food, the research on sensory perception of pungency ofZ. bungeanumbecomes more important and necessary. This article first determined the sensory recognition threshold and just noticeable difference of pungency ofZ. bungeanum. The pungent extract, containing hydroxyl α-sanshool (63.6%), hydroxyl β-sanshool (22.8%), and hydroxyl γ-sanshool (7.4%) fromZ. bungeanumwas used as the tested sample prepared in ethanol–water solution. Ten selected assessors participated in three sessions of sensory tests in standard sensory evaluation booths established according to ISO 8589 by following two-alternative forced choice procedure. The data showed that the recognition threshold was 0.036 mg pungent extract per 1 mL ethanol–water solution and just noticeable difference exponentially increased with the increase of the concentration of pungent extract solution. The response of pungency among assessors followed Weber’s Law with a stable Weber fraction (0.118) from 0.0360 to 0.500 mg pungent extract per 1 mL. Nevertheless, the fraction changed when the concentration of pungent extract solution was above 0.500 mg per 1 mL. [ABSTRACT FROM PUBLISHER]

The effects of different wash times (2 and 5 min) with tap and ozonated water on the removal of nine pesticides from olives and the transfer ratios of these pesticides during olive oil production were determined. The reliability of the analytical methods was also tested. The applied methods of analysis were found to be suitable based on linearity, trueness, repeatability, selectivity and limit of quantification all the pesticides tested. All tap and ozonated water wash cycles removed a significant quantity of the pesticides from the olives, with a few exceptions. Generally, extending the wash time increased the pesticide reduction with ozonated water, but did not make significant differences with tap water. During olive oil processing, depending on the processing technique and physicochemical properties of the pesticides, eight of nine pesticides were concentrated into olive oil (processing factor > 1) with almost no significant difference between treatments. Imidacloprid did not pass into olive oil. Ozonated water wash for 5 min reduced chlorpyrifos, β-cyfluthrin, α-cypermethrin and imidacloprid contents by 38%, 50%, 55% and 61% respectively in olives. [ABSTRACT FROM AUTHOR]

A simple low cost method has been developed and validated for the determination of trace amounts of palladium (II) ions in water and fertilizer samples. The method is based on the reaction of palladium (II) ions with the reagent neothorin (2-(2-arsonophenylazo) chromotropic acid disodium salt). The complex formed exhibits an absorption maximum at 567 nm ( λ max ) in Britton–Robinson (BR) buffer (pH = 2). The corrected absorbance of the formed complex at λ max was obtained by employing a β-correction spectrophotometric method. The Beer–Lambert law and Ringbom's plots of the coloured palladium reagent complex were obeyed in the concentration ranges of 0.05–2.7 and 0.1–2 μg mL −1 palladium (II) ions, respectively, with relative standard deviations in the range of ±1.3–2.1%. The limits of detection (LOD) and quantitation (LOQ) of the procedure were 0.011 and 0.04 μg mL −1 palladium, respectively. The proposed method was applied for the analysis of palladium (II) ions in spiked tap, mineral and underground water samples. The results of the developed method were satisfactorily compared with the data obtained by the inductively coupled plasma-mass spectrometric (ICP-MS) method. Statistical comparison of the results of the proposed method with those obtained by the standard method revealed no significant differences in accuracy and precision. The developed method offers a simple system coupled with good reproducibility, accuracy, ruggedness and cost effectiveness. [ABSTRACT FROM AUTHOR]

This article examines the meaning and experience of retention and withdrawal in higher education from the perspective and voices of non-traditional adult students. It draws on UK biographical data from a European study on access, retention and withdrawal. Withdrawal is perceived negatively by higher education institutions and policymakers as it has an economic cost and reflects on the efficiency of an institution and the student who leaves is viewed as a failure. This article challenges the “traditional” view and argues that non-completion is not always a negative act as many of the students who left in this study talked about the benefits they had gained in terms of learning, identity and the development of the self. Two in-depth biographical case studies are outlined: one student who completes and one who leaves. Both employed their agency and determination in ways which were positive to them but different. [ABSTRACT FROM PUBLISHER]