Search

Dispersive liquid-liquid microextraction (DLLME) is a useful preconcentration technique but its direct application is limited to aqueous samples. Two pretreatment methods for solid samples, QuEChERS (quick easy cheap efficient rugged and safe) and a standard method, were used to isolate four polycyclic aromatic hydrocarbons (PAHs) from the sample matrix. However, since these methods result in analyte dilution, DLLME was used to augment them by concentrating the analytes from 8.0 mL of sample into 150 ��L of 1,2-dichloroethane. Under the optimum conditions, the instrumental detection limit was enhanced by approximately 100-fold for chrysene, benzo[a]pyrene, benz[a]anthracene, and benzo[k]fluoranthene with corresponding detection limits of 29, 29, 30, and 28 ng/L, respectively. The precision of the method based on inter-analyst and inter-day analysis yielded relative standard deviations less than 9.0 and 4.0%, respectively. The optimized method was applied to snail samples spiked at 5.0, 10, 20, and 50 ng/g and the recoveries were nearly 100%. Matrix matched standards were also used to determine the recoveries; the results did not vary significantly from the direct calibration recoveries.

Steam explosion (SE) was a friendly environmentally pretreatment method. In this study, the effect of steam explosion (SE) pretreatment on structure and α-glucosidase inhibitory activity of Ampelopsis grossedentata polysaccharides was evaluated. Two novel polysaccharides (AGP and AGP-SE) were extracted, isolated, purified and analyzed by NMR, FT-IR and methylation. The results indicated that AGP mainly consisted of Rha, Xyl, Glc, and Ara with a molecular weight of 2.74 × 103 kDa and AGP-SE mainly consisted of Man, Ara, and Gal with a molecular weight of 2.14 × 103 kDa. Furthermore, the backbone of AGP and AGP-SE were mainly composed of 5)-Araf-(1→, -Glcp-(1→, 6)-Glcp-(1→, 6)-Galp-(1→, 3,6)-Manp-(1→, and 2,3,6)-Glcp-(1→. Finally, we demonstrated that all polysaccharides exhibited obviously α-glucosidase inhibition activity and mixed type inhibition. AGP-SE had better α-glucosidase inhibition activity and the binding affinity KD on α-glucosidase by using Surface Plasmon Resonance (SPR) than AGP. Overall, SE pretreatment is an effective method for extracting polysaccharide and provides a new idea into the improvement of biological activity.

In this study, gelatin from camel bones (Camelus dromedarius) at three different ages (2.5, 4.5 and 7 years old) was extracted using heating and chemical pretreatment methods. The extraction process was conducted by using hydrochloric acid (0.5 M) (at room temperature 25°c for 72 h) to demineralize the bones and partially hydrolyze the collagen followed by neutralizing with 4% ammonium sulphate. Extraction of camel bone gelatin (CBG) was carried out with distilled water (1:3, w/v) at 75 °C for 3 h, followed by extraction temperature at 90 °C for 1 h resulting in a yield of dry bases ranging from 21.3 to 23.9%. Camel bone gelatin had high protein content (89.31–93.3%), optimum moisture (6.0%), and low ash content (3.62%). The rheological properties, ATR-FTIR and bloom gel, were also investigated. The gel strength (GS) of the camel bone gelatin ranged from 107 to 192 g. The gelatin produced showed good quality and did not differ from other commercial gelatins. The produced gelatin could be useful for food and pharmaceutical implementation.

The preparation and characterization of a matrix reference material for aflatoxin M1 in milk powder is described. Milk powder samples containing aflatoxin M1 were found in the screened natural milk samples. The preparation of matrix milk powder samples was developed through steps by vacuum concentration, spray-drying, cooling, mixing, weighing and packaging, and irradiation. This paper has developed a method for the determination of aflatoxin M1 in milk powder by isotope dilution liquid chromatography–tandem mass spectrometry (ID-LC-MS/MS) with immunoaffinity extraction as the pretreatment method, which was validated and determined the content of aflatoxin M1 in milk powder accurately. The homogeneity was studied by analyzing in triplicate for their aflatoxin M1 contents by ID-LC-MS/MS using random sampling schemes. The short-term stability was evaluated at three different storage temperatures (4, 25 and 50 °C) for 0, 3, 5, 7, 14 days, the long-term stability study comprised of measurement after 0, 1, 3, 6, 9, 12 months after storage at 4 °C, and then, analyses were investigated by ID-LC-MS/MS. After the combination determination of 8 laboratories, the final quantity value and expanded uncertainty of matrix reference material of aflatoxin M1in milk powder were: 0.49 ± 0.11 μg/kg, k = 2, P = 0.95, and the matrix reference material is homogenous and stable at 4 °C for at least 12 months, which can provide quality assurance for the later detection accuracy.

This study established a method for the simultaneous determination of 74 pesticide residues in Panax notoginseng by QuEChERS pretreatment method coupled with GC-MS/MS, and carried out pesticide residue analysis on 20 batches of market samples in China. The samples were extracted with acetonitrile, cleaned up with primary secondary amine (PSA) and octadecylsilane (C18) and determined by GC-MS/MS in multiple reaction monitoring (MRM) mode. Matrix-matched calibration was recommended to combat the matrix effect. A good linearity was observed in the range of 10 − 500 ng/mL with correlation coefficients ≥ 0.9950. The mean recoveries for most of the pesticides were in the range of 70% − 120% with RSD

A method for quantitative determination of the main active ingredient in traditional Chinese medicine was developed and validated, using liquid-liquid chromatography combined with high performance ...

This study deals with the extraction of essential oil from betel leaf using an ultrasound pretreatment method. The sonication time, operating temperature and power have been optimised on the basis ...

Postmortem serum urea has been demonstrated as an objective indicator for the forensic diagnosis of cause of death. However, samples used in postmortem biochemical analysis are always affected by hemolysis. To investigate whether hemolysis affects the biochemical analysis of urea and to explore the feasibility of using ultrafiltration to process hemolyzed blood samples, three different levels of hemolyzed blood samples were used to assess the influence of hemolysis on postmortem biochemical analysis of urea, and two ultrafiltration methods were used to process the hemolyzed blood samples. Bias% was used to assess the interference of hemolysis. Our results showed that heavy hemolysis had a significant influence on the biochemical analysis of urea. Both ultrafiltration methods in the present study could significantly reduce the interference of hemolysis, with the |bias%| of methods A and B decreasing from 69.74% ± 99.14% to 12.18% ± 7.23% and 10.77% ± 8.09%, respectively, compared to the original serum. After regression correction, there was no significant difference between the urea concentration in the ultrafiltrates of the two ultrafiltration methods and that in the original serum, which suggested that the postmortem serum urea concentration could be estimated by the corrected urea concentration in the ultrafiltrate. The current study also provided possible pretreatment methods for postmortem biochemical analysis of other biomarkers in hemolyzed blood samples of forensic practice.

In the present work, a counter current salting-out homogenous liquid–liquid extraction combined with deep eutectic solvent-based–solidification of floating organic droplet-dispersive liquid–liquid ...

As consumer awareness of heavy metal content in textile increased, it is necessary to develop analytical methods that identify and quantify heavy metals. In order to comprehensively investigate the potential risks of antimony (Sb) in recycled polyester fiber to humans health, this study developed acid digestion method, with the condition that the volume ratio of concentrated sulfuric acid to hydrogen peroxide was 1, and digested at 200°Cfor 1.5h, which produced clear and colorless solutions.Currently, microwave and dry ashing are also common methods for digesting polyethylene terephthalate samples. Three pretreatment methods for determining the content of Sb in recycled polyester fibers was evaluated. Results showed that inductively coupled plasma-optical emission spectrometry (ICP-OES) analysis of acid digested recycled polyester samples resulted in Sb content higher than for the microwave and dry ashing digestion methods which incompletely digest recycled polyester. Moreover, compared with microwave digestion and dry ashing, acid digestion had a low detection limit of 0.0116 ug/mL, a high spike recovery of 82% to 106% and the RSD value less than 2%, which indicates that the data was accurate and reproducible. Therefore, in this study, acid digestion - ICP-OES was an effective method for detecting the content of heavy metal Sb in recycled polyester.

In this study, we investigated the effect of sample pretreatments (ultrasonication and alkaline extraction) on total organic carbon (TOC) measurements for water samples containing suspended solids (SS) of four different origins (algae, soil, sewage sludge, and leaf litter) to more clearly assess the impact of particulate organic carbon (POC) in water. The effects each of ultrasonication (power, pulse, etc.) and alkaline extraction condition (concentration, time, etc.) on the TOC recovery and precision were investigated, and the results were compared with those of a new sample pretreatment method combining both methods. Alkaline treatment (0.01 mol/L NaOH) showed higher precision than ultrasonication (100/5 on/off pulse), and notably, the differences among the measured TOC values in samples of different origins were also further reduced in the alkaline treatment. This suggests that the ultrasonic pretreatment results can be mainly attributed to the increase in POC recovery through particle size reduction, whereas the alkaline treatment results are achieved through the enhancement of POC solubilization. It is also particularly noteworthy that a higher TOC recovery of 87.6% ± 7.4% with a higher precision of 8.4% could be obtained using the combined method, compared to each treatment (ultrasonic: TOC recovery 34.7%, relative standard deviation 63.1%; alkaline: 49.6% and 23.0%, respectively). Thus, simultaneous pretreatment with ultrasonication and alkaline extraction is expected to increase the oxidation rate of organic matter and the homogeneity of the samples, minimizing the loss of POC measurement values, and thereby improving the reliability of the TOC measurements of water samples containing SS.

A simple, reliable and environmentally friendly pretreatment method for the simultaneous determination of ten aminoglycoside residues in environmental water samples was established by lyophilizatio...

Purpose: This study aimed at investigating the masking effect and depth of penetration of two resin infiltrants (ICON ® and unfilled adhesive resin) on artificial white spot lesions after different pretreatment methods (15% hydrochloric acid, 37% phosphoric acid and air abrasion through micro etcher) Materials and methods: Artificial white spot lesions were produced in enamel slabs from 60 freshly extracted permanent human anterior teeth (extracted from diabetic patients). The samples were divided into two main groups: resin infiltrant; ICON ® (B1) and adhesive resin bond; ONE-STEP® Universal Dental Adhesive (B2). Each group was subdivided into three subgroups according to the pretreatment used; (HCl 15%) was applied in (A1), (H3PO4 37%) was applied in (A2) and aluminum oxide particles (50/90 µm), through micro etcher was applied in (A3). The assessment of colour was performed by a spectrophotometer in three distinct stages: baseline, after the production of artificial caries and after infiltration treatment expressed in L*, a* and b* values. To analyze measurement results, the chromatism value, ΔE was used to quantify the overall differences of the colors. Results: All the test groups showed no statistically signifiant differences between each other where the highest value was recorded with the adhesive bond after micro-etching 2.250 ± 0.192 and the lowest value was recorded with the adhesive bond after HCl pre-treatment 1.710 ± 0.244 (Statistical significance is achieved when the P-value ≤ 0.05). Conclusion: Both tested infiltrants reacted similarly and the three tested pretreatment methods were equally effective.

In this study, seven pretreatment methods for chromium speciation in tanned leather were evaluated: acidic mineralization, ethylenediaminetetraacetic acid (EDTA) extraction, diethylenetriaminepentaacetic acid (DTPA) extraction, alkaline extraction (NH4OH), ammonium nitrate extraction (NH4NO3), water extraction, and phosphate buffer extraction. Acidic mineralization permitted the decomposition of the organic matter and ensured the complete digestion of leathers, giving access to the total content of chromium in each sample using inductively coupled plasma-atomic emission spectrometry (ICP-AES). From all the extractant media tested, EDTA proved to be the most efficient, allowing the extraction of Cr(VI) and Cr(III) as a Cr(III)-EDTA complex, quantitatively. Method validation is presented for EDTA extraction and direct mineralization. For the EDTA extraction, method detection limit (MDL) and method quantification limit (MQL) for total Cr in leather were 3.4 ppb and 11.2 ppb (µg of total Cr per L of extraction solution), respectively. Due to the lack of leather certified reference materials (CRMs) for Cr(VI), accuracy was evaluated by spiking leather samples with a Cr(VI) solution. The spike recovery of EDTA microwave assisted extraction ranged from 91.0 to 108.6%. Interday precision was also evaluated and all variation coefficients were below 5%, for both mineralization and EDTA extraction. This article provides an efficient procedure to extract quantitatively chromium from leather, while maintaining the speciation, which can be further followed by ion chromatography-inductively coupled plasma-mass spectrometry (IC-ICP-MS).

Combined pretreatment using CaO and the liquid fraction of digestate (LFD) was proposed as an eco-friendly pretreatment method for high-quality anaerobic digestion (AD). In this study, rice straw w...

Human milk oligosaccharides (HMOs) maintain and promote infant health. Most of the current methods for HMOs quantitation require labor-intensive and time-consuming steps for sample preparation. This study presents two very simple and easy-to-operate pretreatment methods, requiring either ultrafiltration or centrifugation to separate free oligosaccharides from whole fat human milk and other milk matrix before oligosaccharides labeling for quantifying HMOs using ultrahigh pressure liquid chromatography with fluorescence detection. A single chromatography run quantified 15 sialylated and neutral HMOs with high sensitivity (with an LOD less than 8 pg for all HMOs tested: about 1 pg for 2'-fucosyllactose, 3-fucosyllactose, 4'-galactosyllactose, 3'-galactosyllactose, and 6'-galactosyllactose) and good linearity with coefficient of correlation above 0.999. Accuracy and precision were satisfactory for both pretreatment methods. Overall, the centrifugation pretreatment was efficient and reliable for samples with high levels of oligosaccharides, and the ultrafiltration pretreatment was especially suitable for samples with low oligosaccharide abundance.

Background: Tobacco (Nicotiana tabacum L.), is an important economic crop. In China, the use of rimsulfuron and haloxyfop-P-methyl herbicides for weed management during the planting period is necessary to improve the production of tobacco. Objective: To establish and validate a quick, easy, cheap, effective, rugged, and safe LC-MS/MS method to determine rimsulfuron, haloxyfop-P-methyl, and haloxyfop in tobacco leaf samples. Methods: We optimized MS/MS conditions and chromatographic conditions for optimal detection conditions. The extraction solvent and sorbent were optimized, and the analysis of variance was applied to analyze the pretreatment method to obtain the optimal pretreatment conditions. Results: The validation results showed that the proposed method exhibited good linearity (R2 > 0.9978), satisfactory recovery (72.51–101.60%) and low LOQ (0.02–1.00 mg/kg). The matrix effects of the three analytes in the two tobacco leaf matrixes were different. The dissipation results showed that the half-lives of rimsulfuron and haloxyfop-P-methyl in fresh tobacco leaf samples were ranged from 2.4 to 3.7 days. The final residues of rimsulfuron, haloxyfop-P-methyl, and haloxyfop in flue-cured tobacco leaf samples were all lower than the LOQ. Conclusions: The results demonstrate that the developed method could be used to detect rimsulfuron, haloxyfop-P-methyl, and haloxyfop in tobacco leaf matrixes. Highlights: A method for simultaneous determination of rimsulfuron, haloxyfop-P-methyl, and haloxyfop in tobacco leaf samples with high sensitivity has been established for the first time.

The volatile methylisiloxanes (VMSs) D4, D5 and D6 have been included in the Candidate List of Substance of Very High Concern (SVHC) by European Chemicals Agency (ECHA) in June 2018. In response to the concerns from the recent SVHC, this study presents three pretreatment methods including purge and trap (P&T), solid-phase microextraction (SPME) and ultrasound-assisted solvent extraction (UASE) combined respectively with gas chromatography-mass spectrometry (GC-MS), for detection of 9 VMSs in food-contact silicone rubber products. Under their optimal operation conditions, three methods were validated. Compared with SPME-GC-MS and UASE-GC-MS, P&T-GC-MS method showed the lower method detection limits (8.40 × 10−4–1.95 × 10−3 mg/kg), the higher recoveries (91.05%–97.48%) and the good %RSD (7.6–11.9%). Considering to be of sensitivity, accuracy, stability, fully-automatic and solvent-free operation, P&T-GC-MS method was finally applied to quantify 9 VMSs in 56 commercial food-contact silicone rubber products. The results showed that 8 VMSs were found and their total contents varied from 17.97 mg/kg to 645.27 mg/kg in the 28 silicone rubber teats, meanwhile, D3, D4, D5 and D6 were detected and their total contents varied from 5.80 mg/kg to 1.45 × 103 mg/kg in the 28 pieces of silicone rubber bakeware.

In order to analyze the bioavailable oxytetracycline (OTC) contents of soils, a new high-efficiency and economical pretreatment method was established using a molecularly imprinted polymer (MIP) wi...

A novel extraction method was established to determine the water-extractable (available) content of sulfamethoxazole (SMX) in soil. The SMX imprinted polymers (MIPs) were synthesised and the perfor...

Cell metabolomics is a valuable tool in oncology. To obtain a valid description of the intracellular metabolome, sample pretreatment is critical to the metabolomics workflow, as this step might influence the reliability of research outcomes. Here we report a systematic investigation to optimize each step of the sample preparation. We explored four quenching protocols, three disruption protocols and seven extraction protocols, and assessed them for effectiveness and robustness by profiling different kinds of representative metabolites by the LC-MS technique using the human glioma cell line U87MG as a model. The optimized pretreatment method for global metabolomics was as follows: after the cells were washed with PBS, cell metabolism quenching was completed within five minutes with 60% methanol (buffered with 0.85% (w/v) AMBIC) at −40 °C. Then, 80% methanol was added and three freeze–thaw cycles were completed to extract metabolites, which could eliminate environmental stress and allow broad coverage of the authentic intracellular metabolome. We also highlighted the advantages and disadvantages of some preanalytical processes for specific metabolites. In addition, the influences of different cell collection batches and liquid nitrogen storage durations were noted. The results suggested the risk of non-physiological or misleading results when using cell samples cultured in different batches or subjected to long-term storage.

Metal-organic frameworks (MOFs) has excellent adsorption performance, herein, three kinds of common MOFs were used for the adsorption of sulfamethazine (SM2) in milk, then enzyme-linked immunosorbent assay (MOF-ELISA) was established. Firstly, NH2-UiO-66, NH2-MIL-101, and ZIF-8 were successfully prepared and their adsorption characteristics for SM2 were investigated. The kinetic models of the three MOFs were more in line with the pseudo-second-order adsorption kinetics, and the saturated adsorption capacity of NH2-UiO-66, NH2-MIL-101, and ZIF-8 for SM2 at 298K were 139.64, 29.98, and 36.5 mg/g, respectively. Using three different MOFs as adsorbents, the pretreatment of milk samples could be completed within 1 h, the half inhibitory concentrations (IC50) of MOF-ELISA were 1.26, 1.86 and 2.74 ng/mL, the limit of detections (LOD) was 0.05, 0.12, and 0.19 ng/mL and the recovery rate were from 82.30% to 105.62% with the intra-day coefficient of variations (CVs) below 5.81% and inter-day CVs below 7.21%. Detection results showed good correlations with LC-MS/MS (R2>0.99), indicated that MOFs could effectively eliminate the interference of sample matrix, and has the potential to become a general pretreatment method for the detection of various matrices residues in food safety monitoring.

Sample pretreatment process is usually performed before real sample detection. Extraction is one of the most prevalent pretreatment methods. Due to the unequal solubility in two liquid phases, target is extracted (usually from water to organic phase) and further detected with laboratory instruments. Although the analytical instruments have high sensitivity and selectivity, they are relatively expensive and require skilful hands, which is restricted to laboratory use. Here, paper-based analytical devices (μPADs) for measuring samples extracted with organic solvents were tested. The μPADs were employed as a filter for buffer exchange, allowing the transfer of targets from organic solvent to water-based buffer, which could be specifically detected by water-based assays. As an example, polychlorinated biphenyls (PCBs) in n-hexane were detected with aptamer and gold nanoparticles (AuNPs) on μPADs within 30 min. The result of colour change can be recognized from 70.0 ng/L with a low loading amount (0.5 μL). Instead of laboratory instrumental analysis with relative high cost, this assay showed the promising utility of μPADs for target detection after sample pretreatment, which could be utilized as a general platform for inexpensive onsite detection.

We here present a comparison of methods for the pretreatment of a batch of tree rings for high-precision measurement of radiocarbon at the Aarhus AMS Centre (AARAMS), Aarhus University, Denmark. The aim was to develop an efficient and high-throughput method able to pretreat ca. 50 samples at a time. We tested two methods for extracting α-cellulose from wood to find the most optimal for our use. One method used acetic acid, the other used HCl acid for the delignification. The testing was conducted on background 14C samples, in order to assess the effect of the different pretreatment methods on low-activity samples. Furthermore, the extracted wood and cellulose fractions were analyzed using Fourier transform infrared (FTIR) spectroscopy, which showed a successful extraction of α-cellulose from the samples. Cellulose samples were pretreated at AARAMS, and the graphitization and radiocarbon analysis of these samples were done at both AARAMS and the radiocarbon dating laboratory at Lund University to compare the graphitization and AMS machine performance. No significant offset was found between the two sets of measurements. Based on these tests, the pretreatment of tree rings for high-precision radiocarbon analysis at AARAMS will henceforth use HCI for the delignification.

With application of PLS regression and SVR, quantitation models of near infrared diffuse reflectance spectroscopy were established for the first time to predict the content of volatile basic nitrogen (TVB-N) content in beef and pork. Results indicated that the best PLS model based on the raw spectra showed an excellent prediction performance with a high value of correlation coefficient at 0.9366 and a low root-mean-square error of prediction value of 3.15, and none of those pretreatment methods could improve the prediction performance of the PLS model. Moreover, comparatively the model obtained by SVR showed inferior quantitative predictive ability (R = 0.8314, RMSEP = 4.61). Analysis on VIP selected wavelengths inferred amino bond containing compounds and lipid may play important roles in the development of PLS models for TVB-N. Results from this study demonstrated the potential of using NIR spectroscopy and PLS for the prediction of TVB-N in beef and pork while more efforts are required to improve the performance of SVR models.

With the increase in demand, artificially planting Chinese medicinal materials (CHMs) has also increased, and the ensuing pesticide residue problems have attracted more and more attention. An optimized quick, easy, cheap, effective, rugged and safe (QuEChERS) method with multi-walled carbon nanotubes as dispersive solid-phase extraction sorbents coupled with surface-enhanced Raman spectroscopy (SERS) was first proposed for the detection of deltamethrin in complex matrix Corydalis yanhusuo. Our results demonstrate that using the optimized QuEChERS method could effectively extract the analyte and reduce background interference from Corydalis. Facile synthesized gold nanoparticles with a large diameter of 75 nm had a strong SERS enhancement for deltamethrin determination. The best prediction model was established with partial least squares regression of the SERS spectra ranges of 545~573 cm&minus, 1 and 987~1011 cm&minus, 1 with a coefficient of determination (R2) of 0.9306, a detection limit of 0.484 mg/L and a residual predictive deviation of 3.046. In summary, this article provides a new rapid and effective method for the detection of pesticide residues in CHMs.

Benzimidazoles, commonly used as pesticides and veterinary drugs, have posed a threat to human health and the environment due to unreasonable use and lack of valid regulation. Therefore, an up-to-date and comprehensive summary of the pretreatment and analytical approaches in different substrates is urgently needed. The present review consequently updates and covers various newly developed pretreatment methods (e.g., cationic micellar precipitation, magnetic-solid phase extraction, hollow fiber liquid phase microextraction, disperse liquid-liquid microextraction-solidified floating organic drop, stir cake sorptive extraction, solid phase microextraction method, QuEChERS, and molecular imprinted polymer-based methods) since 2005. The review also elaborates and discusses different determination methods (e.g., newly developed HPLC and related methods, improved spectrofluorimetry methods, capillary electrophoresis, and the electrochemical sensor). Furthermore, some critical points and prospects are highlighted, to describe the trends in this area.

As highly toxic substances, N-nitrosamines (NAs) have been proved to cause carcinogenesis and mutagenesis in humans. Therefore, to carefully monitor safety and preserve human health, the development of rapid, accurate, and high-sensitivity determination methods of NAs is of substantial importance. This review provides a current-status comprehensive summary of the pretreatment and determination methods of NAs in various samples since 2010. Common pretreatment methods that have been used to extract and purify targets include solid-phase extraction, liquid-liquid extraction and various microextraction methods, such as solid-phase microextraction and liquid-phase microextraction, among others. Determination methods include liquid chromatography, gas chromatography, supercritical fluid chromatography and electrochemical methods, among others. In addition, we discuss and compare the advantages and disadvantages of various pretreatment and analytical methods and examine the prospects in this area.

We aimed to establish an automated versatile sample preconcentration method based on the modified immunomagnetic beads, which was utilized to enrich for aflatoxin B1 from the matrices. The critical main parameters affecting the extraction efficiency, such as usage amount of immunomagnetic beads, reaction time, elution time, and blending way were investigated. Under the optimized conditions, the content of aflatoxin B1 was analyzed by high-performance liquid chromatography, the mobile phase consists of water-acetonitrile-methanol (42:18:10, v/v/v), and fluorescence detection was performed with excitation and emission wavelengths at 360 and 440 nm, respectively. Moreover, the performance of preconcentration method was compared with the conventional method based on the immunoaffinity column. The accuracy of two clean-up methods was within the error range. In addition, the stability and recyclability of the immunomagnetic beads was studied by recycling them five times. The results for the respective analysis in various samples demonstrated that the developed extraction platform provides a promising approach that is simple, rapid, sensitive, and easy to use.

Japanese police conduct highly sensitive and quick blood tests to detect human hemoglobin (Hb), because bloodstains left at a crime scene have probative value of circumstantial evidence in a criminal investigation. Although DNA detection from a bloodstain is a useful tool to identify an individual, doing so requires evidence that the bloodstain is of human origin. Stimulant drug abuse and dependence causes major social problems and crimes in Japan, and bloodstains are often found inside syringes seized from drug abusers. In this case, Hb often cannot be detected by conventional testing as high concentrations of stimulants, such as methamphetamine hydrochloride (MA), in blood trigger polymerization of Hb molecules, which become insoluble under non-reducing conditions and can no longer be detected by immunochromatographic detection kits. To overcome this problem, we analyzed methods to detect denatured Hb from bloodstains contaminated with MA. Reduction of polymerized Hb with a strong denaturing agent was required to solubilize polymers into monomers, suggesting that Hb aggregation is caused by aberrant formation of disulfide bonds. Based on these results, we established a pretreatment method, called Fukui’s Reduction and Eiken’s Dilution (FRED), that enables highly sensitive detection of human Hb from bloodstains mixed with MA by reducing and refolding of denatured Hb. This powerful method can be applied to blood that has been boiled or has otherwise deteriorated for over 20 years.

RATIONALEAlthough the analysis of skeletal remains dominates the study of ancient dietary stable isotopes, mummified bodies also allow short‐term diet to be studied through the analysis of soft tissues. The application of resins, waxes and oils during mummification can affect the results obtained. This study assesses a range of methods for removing such substances from mummified tissue.METHODSAn experimental mummification model following ancient Egyptian methods was created using a modern pig leg. Sub‐samples of skin, muscle and bone were removed and coated with a range of substances used in Egyptian mummification. Four methods were used to clean these samples before the measurement of the carbon and nitrogen stable isotope ratios of their gelatinised collagen content using a ThermoFinnigan Flash Elemental analyser coupled to a DeltaPlus XL isotope ratio mass spectrometer via a ConFlo III interface.RESULTSThe results showed that embalming materials can significantly affect dietary stable isotope ratios, and that these substances are most effectively removed using a mixture of polar and non‐polar solvents. Results indicate that bone samples demineralised with HCl and skin samples produce more accurate results than bone samples demineralised with EDTA or muscle samples.CONCLUSIONSThe choice of tissue and the preparation methods used can have a significant effect on the accuracy of stable isotope data obtained from mummified tissue, particularly when embalming materials are also present. A mixture of solvents appears to be a more effective cleaning agent than a single solvent. Demineralisation with HCl is preferable for well‐preserved bone as used in this study, but whether this is the case for more fragile, less well‐preserved bone requires further study. Skin samples produce more consistent data than muscle, but visually distinguishing between these tissues is not simple on ancient mummies.

Coumarins are widely used due to their wide range of biological activities, but the long-term or excessive use of coumarin flavors can pose serious health hazards. Therefore, sensitive and specific methods for the quantification of these compounds in different matrices have been developed. In this review, an updated overview of the latest trends in sample preparation techniques and methods used to detect coumarins from March 2012 to April 2019 is provided. This study reviews different analytical methods (such as liquid chromatography coupled with different detectors, electrochemical sensors, capillary electrophoresis, etc.) and different pretreatment methods (such as liquid-liquid extraction, solid-phase extraction, dispersive liquid-liquid microextraction, etc.). Different methods for the pretreatment and determination of coumarins in plant, food, environmental, pharmaceutical and biological samples are summarized, discussed and compared.HighlightsProgress in pretreatment and analytical methods of coumarins are summarized.Fundamentals, instrumentation and applications of purification and quantification are summarized and compared.Optimization of experimental conditions are discussed.Newly emerged eco-friendly methods are introduced.

Although immunomagnetic separation is a useful sample pretreatment method that can be used to separate target pathogens from a raw sample, it is challenging to remove unbound free magnetic nanoparticles (MNPs) for colorimetric detection of target pathogens. Here, size-based filtration was exploited for the rapid on-site detection of pathogens separated by immunomagnetic separation in order to remove unbound free MNPs using a finger-powered microfluidic device. A membrane filter and an absorbent pad were integrated into the device and a mixture of unbound free MNPs and MNP-bound Escherichia coli (E. coli) O157:H7 was dispensed over the membrane filter by pressing and releasing the pressure chamber. A colorimetric signal was generated by MNP-bound E. coli O157:H7 while unbound free MNPs were washed out by the absorbent. Furthermore, the colorimetric signals can be amplified using a gold enhancer solution when gold-coated MNPs were used instead of MNPs. As a result, 102 CFU/mL E. coli O157:H7 could be detected by the enhanced colorimetric signal on a proposed device.

In view of the high polarity and ubiquitous occurrence of perchlorate, achieving an ultra-trace analysis has become a challenging task. The present study aimed to develop a simple and generic pretreatment protocol based on cold-induced liquid–liquid extraction to efficiently extract perchlorate from tea and dairy products and remarkably decrease potential matrix interferences and laborious cleanup. By optimizing the pretreatment conditions, the enrichment factor of perchlorate increased by 7.79 times under the compromise between the matrix effect and extraction recovery. The validated method presented satisfactory selectivity, linearity, accuracy, precision, and matrix effect, providing recoveries of 78.2%–106.2% with RSDrranging from 1.2% to 7.9% and RSDRless than 10.7% for tea and dairy products. This pretreatment protocol depended only on shaking, freezing, and centrifugation in one step, without additional equipment or tedious operations, which will be explored to a greater extent in complex biological or food matrices.

Conventional analysis, electronic senses and HS-SPME-GC-MS were applied to evaluate the effects of pretreatment methods and leaching methods on jujube wine quality. Significant differences (p 0.05) in the levels of alcohol content, color, taste and aroma were observed among all the jujube wine samples, in which the pulp and pectase fermented jujube wine was the best among all. Moreover, rather than taste, aroma is the most significantly (p 0.05) affected. In regard to aroma, a total of 182 volatile compounds were identified by HS-SPME-GC-MS. It was found that the blended-into-pulp treatment and the leached-by-pectase treatment had notable positive effects on jujube wine. The pulp and pectase fermented jujube wines exhibited the highest concentration of total volatile compounds as well as alcohols, esters, acids and aldehydes. Thus, the optimal pretreatment method and leaching method for jujube wine fermentation are blended-into-pulp and leached-by-pectase respectively.

In present study, a new sample pretreatment method based on the combination of stirring-assisted ferrofluid-based liquid phase microextraction and dispersive liquid–liquid microextraction has been developed for the extraction of some pesticides (diazinon, deltamethrin, fenpropathrin, phosalone, prometryn, simazine, and terbutryn) from herbal distillate samples. In this method, a few microlitre of a synthesised ferrofluid as an extraction solvent is added into the sample solution containing the analytes and the mixture is stirred at a high rate to increase the contact area between the ferrofluid and sample solution. Then the stirring procedure is stopped and the ferrofluid droplets containing the analytes are collected on the surface of stir bar. In the next step, the stir bar is washed with acetonitrile. In the following, the obtained mixture of acetonitrile and ferrofluid is rapidly injected into deionised water. The ferrofluid droplets are settled down at the bottom of a conical test tube and after back-extraction of the analytes into n-hexane, an aliquot of the extractant phase is injected into gas chromatography–mass spectrometry. Under optimum conditions, the introduced method offered high enrichment factors (1643−1884) and extraction recoveries (82–94%), low limits of detection (3.1–7.3 ng L–1) and quantification (10.3–24.3 ng L–1), and an acceptable repeatability (relative standard deviation ≤ 7.9%).

The effect of direct enzyme addition and other pretreatment methods on VFA production through co-fermentation of primary sludge and external organic waste was studied under initial alkaline (pH 10) and acidic (pH 5) conditions. Beside the direct enzyme cocktail addition, 24-hour enzymatic, ultrasonic, ultrasonic + 24-hour enzymatic and thermal were the other pretreatment methods. Under the alkaline condition, direct addition of enzyme enhanced VFA production by 29-39% throughout the experimental period, whereas there was 37-43% increase in VFA production under the acidic condition only at retention days 1 and 2. VFA composition was dominated by acetic acid (54-67%) and propionic acid (31-46%) under alkaline and acidic condition, respectively. Direct enzyme addition resulted in the increment in the percentage of caproic acid from 8-9% to 16-17%, under the acidic condition. While 24-hour enzymatic pretreatment didn’t show any improvement on VFA production, thermal, ultrasonic + 24-hour enzymatic and ultrasonic pretreatment methods increased VFA production by 18, 14 and 4%, respectively. On the other hand, the pretreatment methods significantly increased biogas production. Experiment without pretreatment achieved maximum biogas production of 392 NmL CH 4 at day 9 while experiments with pretreatments achieved maximum of 679-954 NmL CH 4 in the order of no pretreatment < ultrasonic < thermal < 24-hour enzymatic < ultrasonic + 24-hour enzymatic. The study gives insight into how pretreatment strategy can influence VFA production and composition.

Human beings are easily exposed to formaldehyde (FA) in a living environment. Entry of FA into the human body can have adverse effects on human health, depending on the FA concentration. Thus, a quantitative analysis of FA in blood is necessary in order to estimate its effect on the human body. In this study, a simple and rapid analytical method for the quantitation of FA in blood was developed. The total analysis time, including the pretreatment procedure, was less than 20 min. To ensure a stable analysis, blood samples were stabilized using tripotassium ethylenediaminetetraacetic acid solution, and FA was selectively derivatized using 2,4-dinitrophenylhydrazine as pretreatment procedures. The pretreated samples were analyzed using a high-performance liquid chromatography-UV system, which is the most common choice for analyzing small-molecule aldehydes like formaldehyde. Verification of the pretreatment methods (stabilization and derivatization) using FA standards confirmed that the pretreatment methods are highly reliable in the calibration range 0.012–5.761 ng μL–1 (slope = 684,898, R2 = 0.9998, and limit of detection = 0.251 pg·μL–1). Analysis of FA in the blood samples of a Yucatan minipig using the new method revealed an average FA concentration of 1.98 ± 0.34 ng μL–1 (n = 3). Blood samples spiked with FA standards were analyzed, and the FA concentrations were found to be similar to the theoretical concentrations (2.16 ± 0.81% difference). The method reported herein can quantitatively analyze FA in blood at a sub-nanogram level within a short period of time and is validated for application in blood analysis.

The speciation analysis of arsenic (As) has always received great attention, in which the analysis of complex matrix samples remains challenging, mainly manifested in selection of suitable sample pretreatment methods and sensitive analytical spectrometers. In this work, microwave-assisted extraction of total As and various As species in bones, with their respective determination by ICP-MS and HPLC-ICP-MS, was studied, and was successfully utilized to determine As species in panda and pig bones. The results reveal the content of As ranging from 28 to 75 μg g−1 in the panda bone samples and 0.27 μg g−1 in pig bone, in which >90% is inorganic AsV except for little AsIII and organic As. The method could be applicable to the analysis of diverse bone samples.

Void space in the bean layers will lead to the occurrence of non-fully interacted radiation (NFIR) affecting the reproducibility of NIRS measurements. Void space in addition to being affected by particle size is also influenced by the number/thickness of the bean layers. The objective of this study was to analyze the effect of number of bean layer variation on prediction accuracy of caffeine, chlorogenic acid and trigonelline in Bondowoso green Arabica coffee beans by NIR Spectroscopy (NIRS). The study was conducted using three kind of layers, i.e. 3, 4, and 5 layers, with 100 samples each. Samples were measured by FT-NIR spectrometer in wavelength of 1.000-2.500 nm. The pretreatment method used were second derivative (dg2), the combination of first derivative (dg1) and Multiplicative Scatter Correction (MSC), and the combination of dg2 and MSC, while calibration method used was Partial Least Square (PLS). The results shows that the accuracy of 5 layers was better than 3 or 4 layers. The best calibration and validation for caffeine was obtained by dg2 pretreatment and 6 factors of PLS (r = 0.99; SEC = 0.01%; SEP = 0.01%; and RPD = 5.40), for chlorogenic acid was by dg2 pretreatment and 5 factors of PLS (r = 0.99; SEC = 0.09%; SEP = 0.09%; and RPD = 4.76), whereas for trigonelline was by combination of (dg2, MSC) and 5 factors of PLS (r = 0.99; SEC = 0.01%; SEP = 0.01%; and RPD = 4.86). Therefore, the 5 layers can be used as a reference in NIRS measurement of coffee beans.

Currently, the growing demand on quick, easy and ecological sample pretreatment methods is unquestionable. Such challenge involves also approaches focusing on the analysis of pharmaceuticals and other endogenous compounds in biological matrices, termed as Bioanalysis. Solvent extraction such as liquid-liquid extraction (LLE), derived liquid phase microextraction (LPME) and related approaches such as solid liquid extraction (SLE), proved to be applicable in bioanalysis, as numerous papers have been published in this field. However, their manual performances may suffer from a long-term and laborious preparation, due to the inherent complexity of the biological samples. A high sample-throughput (enabling measurement of tens or hundreds of samples on a daily basis) can be achieved when automation of sample pretreatment is performed, resulting in decreased imprecision and low waste production of hazardous solvents and risky biological materials. Here, robotic systems have a key role, especially when multiple processing (e.g., 96-well plate format) and coupling to modern analytical instrumentation (e.g. LC-MS) are combined. A thorough overview on the up-to-date automations of LLE, LPME, SLE and solid LLE via robotics, is therefore presented. Pharmaceuticals and related compounds determined in classical liquid biological samples (i.e. plasma/serum, whole blood, urine, saliva etc.) and modern dried matrix spots (DMS) were considered as analytes of interest. The methodologies were critically compared to manual setups and among themselves.

To determine the authenticity of Anoectochilus roxburghii, this study presents an application of near-infrared spectroscopy and chemometric methods for evaluating adulteration of A. roxburghii with two cheaper adulterants, i.e. C. Goodyera schlechtendaliana and Ludisia discolor. Partial least squares discriminant analysis models were built for the accurate classification of authentic A. roxburghii and A. roxburghii adulterated at 5-100% (w/w) levels. Partial least squares regression models were used to predict the level of adulteration in the A. roxburghii. After by compared different spectral pretreatment methods, and using interval PLS and synergy interval PLS for variable selection, optimum models were developed. These results show that the NIR spectroscopy combined with chemometric methods offers a simple, fast, and reliable method for classifying and quantifying the adulteration of A. roxburghii.

An integrated technology for preparing proteomics samples was developed based on SCX/SAX mixed beads. Unlike previously reported SISPROT strategies, SCX/SAX mixed beads were used to replace SCX beads. A mixture of BSA and LYZ was chosen as the model protein to evaluate the protein retention behavior of the SCX/SAX beads at pH of 3, 7.4, and 12. The mass ratio of SCX/SAX was optimized using the BCA method. Further, the protein loss caused by pH replacement during digestion was systematically investigated by the SDS-PAGE method. The results indicated that at a pH of 7.4, the optimized mass ratio of SCX/SAX mixed beads was 1:1, and the loading capacity of SCX/SAX mixed beads with the mass ratio of 1:1 was 180 µg, which is almost twice that of SCX beads. Furthermore, pH replacement during digestion did not affect the protein retention behavior of SCX/SAX mixed beads. The improved SISPROT method was used for processing a limited quantity of colon cancer tumor samples. For comparison, the traditional SISPROT method based on SCX beads was used. The results indicated that the number of protein identification, unique peptides and peptide spectrum matching obtained from the two methods were comparable. These results confirmed the applicability of the method as a proteomics reactor. The method is expected to be a more generic sample preparation technology because it can be operated at physiological pH and exhibits significantly improved loading capacity and reduced sample loss compared with those of the traditional SISPROT method.

In this study, we developed a method to evaluate the potentially bioavailable fraction of Pu in agricultural soils by determining their water soluble and exchangeable fractions. Three commonly used pretreatment methods were compared for their ability and performances to process the extracted solutions. Results showed that these three methods were able to obtain consistent Pu concentration results; however, based on the experimental performance factors, we considered that wet-ashing followed by Fe(OH)3 co-precipitation was the best pretreatment method, with which high 242Pu recoveries for the overall process were realized for the water soluble fraction (69.8%) and the exchangeable fraction (70.6%).

A pretreatment method using hyperbranched polyester (HBPE) composite as sorbent based on dispersive micro-solid-phase (d-μ-SPE) extraction preceding high-performance liquid chromatography analysis was developed for the determination of benzoylurea insecticides (BUs) in water samples. Parameters that may influence the extraction efficiency, such as the diameter and the amount of the sorbent, extraction and desorption time and the pH value of the solution, were investigated and optimized using batch and column procedures. Under optimized conditions, good linearity was obtained for all of the tested compounds, with r values of at least 0.9924. The linearity of the method was determined in the range of 1–25 000 μg L−1. The limits of detection (LODs) ranged from 0.024 to 0.068 μg L−1. The recoveries of the four benzoylurea insecticides in water samples increased from 85.50–96.12%. The results confirmed the possibility of using hyperbranched polyester in the determination of relatively hydrophobic trace pesticides residues. Finally, the proposed method was applied to the determination of BUs in water samples with satisfactory results.

Foot-and-mouth disease (FMD), caused by the FMD virus (FMDV), is controlled by vaccine policy in many countries. For vaccine potency, the content of intact virus particles (146S antigens) is critical, and the sucrose density gradient (SDG) fractionation is the gold standard for the quantification of 146S antigens. However, this method has several drawbacks. Although size-exclusion high-performance liquid chromatography (SE-HPLC) was introduced to replace the classic method, its application is generally confined to purified samples owing to the interfering signals. Therefore, we aimed to develop optimal pretreatment methods for SE-HPLC quantification in less purified samples. Crude virus infection supernatant (CVIS) and semi-purified samples with PEG precipitation (PEG-P) were used. Chloroform pretreatment was essential to remove a high level of non-specific signals in CVIS, whereas it caused loss of 146S antigens without the distinctive removal of non-specific signals in PEG-P. Benzonase pretreatment was required to improve the resolution of the target peak in the chromatogram for both CVIS and PEG-P. Through spiking tests with pure 146S antigens, it was verified that the combined pretreatment with chloroform and benzonase was optimal for the CVIS, while the sole pretreatment of benzonase was beneficial for PEG-P.