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Au(i)–SG/Ce(CO3)2 NS conjugated nanoprobe was developed for selective GSH detection. The redox reaction between GSH and the NS could release Ce3+ ions to initiate the intense AIE of Au(i)–SG oligomers.

In this work, we fabricated gold nanoparticles (AuNPs) capped with both polyvinyl pyrrolidone (PVP) and iodine (I2) to act as efficient chemiluminescent coreactants for luminol. AuNPs synthesis was based on the direct chemical reduction of Au3+ with NaBH4 in the presence of PVP-I2 complex. The successful synthesis of PVP-I2@AuNPs was confirmed with scanning electron microscopy (SEM) and UV-vis spectrophotometry. Chemiluminescence (CL) intensity of luminol was greatly enhanced, upon its chemical reaction with chemisorbed I2 on AuNPs surfaces owing to the excellent catalytic activity of AuNPs. The PVP-I2@AuNPs/luminol CL sensing system was successfully applied for determination of Hg2+ ions and the results displayed linearity in a wide range from 0.5 to 2000 nM and an ultrasensitive response to 1.0 nM Hg2+. The detection limit of Hg2+ ions was 0.1 nM, which was 100 times lower than the limit value (10 nM) defined by the U.S. Environmental Protection Agency in drinkable water. This ultrasensitive luminogenic system for Hg2+ detection also exhibited excellent selectivity among 13 types of metals, suggesting that the luminol/PVP-I2@AuNPs system is a promising sensor for real-time detection of Hg2+.

A new chemiluminescence (CL) system, indigo carmine/glucose/hemin/H2O2, has been found and developed for non-enzymatic detection of indigo carmine (IC) and glucose. The CL response increases linearly with IC concentrations from 3.2 μM to 10 mM and glucose concentrations from 0.06 μM to 3.5 mM. The detection limits are 1.45 μM and 15.0 nM for IC and glucose, respectively. This method allows the determination of glucose in blood and urine after simple dilution. The recoveries for the determination of glucose are between 98.5% and 101.0% in blood and between 98.5% and 101.3% in urine. This method shows good sensitivity, selectivity, simplicity, and is low cost, suggesting its promising broad applications.

In this work, a glutathione (GSH) sensing nano-platform using lucigenin as a fluorescent probe in the presence of MnO2 nanosheets was reported for the first time. Unlike the earlier fluorescent detection systems based on MnO2 nanosheets, which depend on Forster resonance energy transfer (FRET) or the dynamic quenching effect (DQE), the mechanism of the quenching process of MnO2 nanosheets on lucigenin fluorescence was attributed mainly to a static quenching effect (SQE) with a minor contribution of the inner filter effect (IFE). A double exponential fluorescence decay of lucigenin was obtained in various MnO2 nanosheet concentrations as a result of their SQE and IFE. Based on this phenomenon and taking advantage of the redox reaction between GSH and MnO2 nanosheets, we have developed a switch-on sensitive fluorescent method for GSH via the recovery of the MnO2 nanosheet-quenched fluorescence of lucigenin. A good linearity range of 1.0–150.0 μM with a low limit of detection (S/N = 3) of 180.0 nM was achieved, revealing the higher sensitivity for GSH determination in comparison with the previously reported MnO2 nanosheet-based turn-on fluorescent methods. The developed fluorescent nano-platform exhibits excellent selectivity with successful application for GSH detection in human serum plasma, indicating its good practicability for GSH sensing in biological and clinical applications.

Tris(4,7'-diphenyl-1,10-phenanthroline) ruthenium (II) dichloride [Ru(dpp)

In this work, a nanosensor chemiluminescent (CL) probe for sensing glutathione (GSH) was developed, for the first time, based on its inhibition of the intrinsic peroxidase-mimetic effect of BSA@AuNCs. The endoperoxide linkage of artesunate could be hydrolyzed by BSA@AuNCs resulting in the release of reactive oxygen species (ROS), and the consequent generation of strong CL emission. By virtue of the strong covalent interactions of –S⋯Au–, GSH could greatly suppress the peroxidase-mimetic effect of BSA@AuNCs, leading to a drastic CL quenching. The CL quenching efficiency increased proportionally to the logarithm of GSH concentration through the linearity range of 50.0–5000.0 nM with a limit of detection of 5.2 nM. This CL-based strategy for GSH tracing demonstrated the advantages of ultrasensitivity, high selectivity and simplicity. This strategy was successfully utilized to measure GSH levels in human serum with reasonable recovery results of 98.71%, 103.18%, and 101.68%, suggesting that this turn-off CL sensor is a promising candidate for GSH in biological and clinical samples.

Background: Cardiovascular diseases are presently the leading causes of death in industrialized countries and expected to become so in emerging countries by 2020. Among these, coronary artery disease (CAD) is the most prevalent manifestation and is associated with high mortality and morbidity. Objective: The aim of this study was to assess the impact of Type II DM on the left ventricular function measured by 2D Speckle tracking Echocardiography in middle aged patients presenting with NSTEMI who will undergo PCI. Patients and methods: This study was carried on sixty middle aged patients (according to WHO, it should be 55 years of age) admitted with NSTEMI who undergoing (PCI) during their admission at Al-Hussein University Hospital, Mostafa Kamel Military Hospital and the International Cardiac Center (ICC) at Alexandria. They divided into two equal groups (Diabetic group and Non-diabetic control group). Results: The result showed that diabetes had a bigger effect on the initial systolic function but with early intervention.The difference in systolic function in both study groups was insignificant though it was a bit better in non-diabetics. Regarding to the site of significant LAD lesion, statistical difference was found in osteal LAD lesions (more in diabetics) and mid LAD lesions (more in non-diabetics). Conclusion: Early intervention in diabetic patients lessens the effect of CAD on the myocardium even if the disease tends to be stronger than non-diabetics early on. The 2D speckle tracking echocardiography is a promising, feasible, and non-invasive modality to evaluate myocardial deformation.

Development of sensing systems for trace metals is highly important because the abnormal concentration of some metals or the presence of some traces of toxic metals is very dangerous. The stripping analysis is an efficient way to detect metals even at low concentrations. Much work has been carried out to develop highly sensitive, stable, reproducible, and cheap electrochemical sensors for metal ions. This review summarizes the recent progress is stripping analysis of trace metals, focusing on works published from 2015 to 2019.

This review gives a summary of applications of different nanomateials, such as gold nanoparticles (AuNPs), carbon-based nanoparticles, magnetic nanoparticles (MNPs), and nano-sized metal organic frameworks (MOFs), in electrophoretic separations. This review also emphasizes the recent works in which nanoparticles (NPs) are used as pseudostationary phase (PSP) or immobilized on the capillary surface for enhancement of separation in CE, CEC, and microchips electrophoresis.

Tyrosinase is a key enzyme in melanin biosynthesis and its serum level is an important biomarker for some dermatoses such as vitiligo and melanoma. Thus, a sensitive and facile assay for tyrosinase activity is in urgent demands. Lucigenin is a well-known chemiluminescent luminophore, but has been rarely been employed for fluorescence detection. In this work, a facile method to detect tyrosinase activity based on lucigenin fluorescence has been reported for the first time. When tyrosinase was mixed with tyrosine, tyrosine was oxidized to generate melanin-like polymers which can effectively quench the fluorescence of lucigenin. A linear range of tyrosinase from 0.25 to 25 μg/mL was obtained with detection limit of 0.2 μg/mL. In addition, a useful platform for screening potential tyrosinase inhibitors was constructed based on the proposed system. The linear range is from 2.5 to 62.5 μg/mL and the detection limit is as low as 1.0 μg/mL for kojic acid, a typical tyrosinase inhibitor.

In this work, we fabricated gold nanoparticles (AuNPs) capped with both polyvinyl pyrrolidone (PVP) and iodine (I

In this study, we reported a facile, one-pot, and "green" synthesis of glutathione-protected gold nanoclusters (GSH@AuNCs) initiated by samarium (Sm3+) lanthanides for the first time. Sm3+ lanthanides more efficiently induced the formation of GSH@AuNCs with significantly enhanced luminescence than other lanthanides or heavy metal ions (Cd2+, Pb2+) did. Using this strategy, a detection for Sm3+ was made with a linearity range of (10.0-100.0 μM) and a limit of detection (LOD) of 0.5 μM. The Sm3+-based GSH@AuNCs were characterized by eco-friendliness, photostability, and low-cost synthesis with low biological toxicity and had great potential in the application for biosensing and bioimaging. They were successfully employed in the detection of dipicolinic acid (DPA), a well-reported biomarker for sensing potential infection by strongly hazardous anthrax spores. A good linear response was obtained for DPA detection ranging from 1.0 to 120.0 μM with a low LOD of 0.1 μM, which was much lower (600 times) than the infectious dosage of anthrax spores (6 × 10-5 M). The detection was due to the strong binding affinity and strong chelation capability of DPA to Sm3+ lanthanides, which caused the dissociation of the aggregates with an obvious decrease or even a turning-off effect of their luminescence.

Herein, we report luminol–silicotungstic acid (STA) chemiluminescence (CL) for the first time. The luminol–STA system resulted in remarkable CL enhancement (65 times) compared with the known classical luminol–H2O2 system because of the generation of the strong oxidizing agent tungsten trioxide from STA. Based on the quenching effect of uric acid, the new CL system is applied for the sensitive and selective assay of uric acid in its pure state (LOD 0.75 nM) and in real human urine with excellent recoveries in the range of 99.6–102.3%. Furthermore, this system permits the efficient detection of STA (LOD, 0.24 μM).

Correction for ‘In situ synthesis of chiral AuNCs with aggregation-induced emission using glutathione and ceria precursor nanosheets for glutathione biosensing’ by Mohamed Ibrahim Halawa et al., Analyst, 2022, https://doi.org/10.1039/d2an00939k.

A new chemiluminescence (CL) system, indigo carmine/glucose/hemin/H2O2, has been found and developed for non-enzymatic detection of indigo carmine (IC) and glucose. The CL response increases linearly with IC concentrations from 3.2 μM to 10 mM and glucose concentrations from 0.06 μM to 3.5 mM. The detection limits are 1.45 μM and 15.0 nM for IC and glucose, respectively. This method allows the determination of glucose in blood and urine after simple dilution. The recoveries for the determination of glucose are between 98.5% and 101.0% in blood and between 98.5% and 101.3% in urine. This method shows good sensitivity, selectivity, simplicity, and is low cost, suggesting its promising broad applications.

In this work, a glutathione (GSH) sensing nano-platform using lucigenin as a fluorescent probe in the presence of MnO2 nanosheets was reported for the first time. Unlike the earlier fluorescent detection systems based on MnO2 nanosheets, which depend on Förster resonance energy transfer (FRET) or the dynamic quenching effect (DQE), the mechanism of the quenching process of MnO2 nanosheets on lucigenin fluorescence was attributed mainly to a static quenching effect (SQE) with a minor contribution of the inner filter effect (IFE). A double exponential fluorescence decay of lucigenin was obtained in various MnO2 nanosheet concentrations as a result of their SQE and IFE. Based on this phenomenon and taking advantage of the redox reaction between GSH and MnO2 nanosheets, we have developed a switch-on sensitive fluorescent method for GSH via the recovery of the MnO2 nanosheet-quenched fluorescence of lucigenin. A good linearity range of 1.0-150.0 μM with a low limit of detection (S/N = 3) of 180.0 nM was achieved, revealing the higher sensitivity for GSH determination in comparison with the previously reported MnO2 nanosheet-based turn-on fluorescent methods. The developed fluorescent nano-platform exhibits excellent selectivity with successful application for GSH detection in human serum plasma, indicating its good practicability for GSH sensing in biological and clinical applications.

In this paper, we developed one-pot facile synthetic approach for preparing fluorescent gold nanoclusters (AuNCs) by utilizing reducing-cum-stabilizing inositol (INOS). The as-prepared INOS protected gold nanoclusters (INOS@AuNCs) have excellent monodispersity with uniform size

N-hydroxyphthalimide (NHPI), a well known reagent in organic synthesis and biochemical applications, has been developed as a stable and efficient chemiluminescence coreactant for the first time. It reacts with luminol much faster than N-hydroxysuccinimide, eliminating the need of a prereaction coil used in N-hydroxysuccinimide system. Without using prereaction coil, the chemiluminescence peak intensities of luminol-NHPI system are about 102 and 26 times greater than that of luminol-N-hydroxysuccinimide system and classical luminol-hydrogen peroxide system, respectively. The luminol-NHPI system achieves the highly sensitive detection of luminol (LOD = 70pM) and NHPI (LOD = 910nM). Based on their excellent quenching efficiencies, superoxide dismutase and uric acid are sensitively detected with LODs of 3ng/mL and 10pM, respectively. Co2+ is also detected a LOD of 30pM by its remarkable enhancing effect. Noteworthily, our method is at least 4 orders of magnitude more sensitive than previously reported uric acid detection methods, and can detect uric acid in human urine and Co2+ in tap and lake water real samples with excellent recoveries in the range of 96.35-102.70%. This luminol-NHPI system can be an important candidate for biochemical, clinical and environmental analysis.

This study demonstrates the synthesis, characterization, and modeling of nickel ferrite nanocomposite, NiFe2O4 (NFC) as an adsorbent for the phenol contaminated aqueous environment. The characterization of the prepared NFC was performed with X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) techniques. The optimization and modeling of phenol removal using NFC was done through central composite design (CCD) and effective parameters of CCD were measured as input variables including the amount of NFC, pH, contact time and initial phenol concentration. The predicted results showed that the adsorption process using NFC as adsorbent had the maximum phenol removal (~99%) under predicted optimal conditions (pH = 7.67, NFC dosage = 0.15 g at room temperature), which also corresponded to the experimental values. In addition, a multilayer feed-forward artificial neural network (ANN) model was used to obtain a speculative phenol removal model. The network was trained for six replications after selection of the best neuron number for hidden layer. The value of MSE trained network was found to be 6.01718e-3 along with regression coefficient (R2 = 0.9934) that indicated satisfactory relationship. Isothermal modeling of phenol adsorption onto NFC was performed using well-known Temkin, Freundlich and Langmuir models and it was clear from the higher R2 value of 0.961 that the Langmuir model was significantly followed by experimental data. The maximum Langmuir adsorption capacity was found to be 274.72 mg/g at the optimal conditions. The obtained results prove that NFC could be an effective adsorbent for elimination of phenol contaminant from aqueous environment.

Allantoin has been reported as a promising biomarker for monitoring of oxidative stress in humans and widely utilized in a variety of topical pharmaceuticals and cosmetics. Currently, the detection of allantoin is achieved by using chromatographic coupled techniques, which needs sample pre-extraction, derivatization, complex matrixes, and expensive instrumentation. Herein we report both the intense chemiluminescence of allantoin with lucigenin and the chemiluminescent detection of allantoin for the first time. The lucigenin-allantoin system demonstrated chemiluminescence emission intensity 17 times higher than that of the classic lucigenin-hydrogen peroxide system. Based on this fascinating phenomenon, a novel chemiluminescence method has been developed for the sensitive and selective allantoin determination with the combination of flow injection analysis. This method shows a linear calibration curve in the range 0.1-3000 μM with a detection limit (3σ/s) of 0.03 μM. Moreover, it was successfully utilized for the determination of allantoin in human eye drop and real urine samples after simple dilution with water. It shows excellent recoveries in the range 94.0-101.7%, and each measurement takes a very short time. This method exhibits potential advantages in the form of simplicity, rapidity, sensitivity, selectivity, and low cost. Allantoin could be an effective candidate for constructing new chemiluminescence systems, and it may provide a broad range of sensing applications.

The implementation of gold nanoparticles (AuNPs) in electrochemical immunoassays of cancer biomarkers has been in place for several years. AuNPs play crucial roles in the development of a convenient interface for the immobilization of antibodies, facilitating the electron transfer process through a developed interface and signal amplification by several orders of magnitude. Additionally, because of the unique properties of AuNPs, AuNPs-based electrochemical immunosensors offer ultrasensitive, biocompatible, rapid and inexpensive sensing approaches with the feasibility of on-line monitoring and simultaneous sensing of multiple cancer biomarkers. Herein, we summarize different synthetic strategies of AuNPs and their main roles in the design of electrochemical immunosensors. Moreover, the different applications of AuNPs in developing electrochemical immunosensors for very common tumor biomarkers such as PSA, CEA, AFP, CA125 and hCG are briefly discussed in this chapter.

Asthma is one of the most common chronic diseases among children and has affected about 300 million individuals worldwide according to the report of the world health organization. Herein, we present the first electrochemiluminescence (ECL) report for the determination of an important antiasthmatic drug (Bambuterol). It was found that bambuterol can act as an efficient coreactant for Ru(bpy)32+ ECL via oxidation-reduction pathway. The electrogenerated reducing species from bambuterol and Ru(bpy)32+ could react together at the surface of gold electrode to generate an intense ECL signal. Based on this new finding, the first ECL study was proposed and optimized for the rapid, highly sensitive, and selective screening of bambuterol in its pure form with a wide linearity of 10.0 nM - 2.0 μM and an ultra-low detection limit of 1.48 nM. The developed system was applied for assaying bambuterol in pharmaceutical preparations. Furthermore, the developed system was also utilized to determine the content uniformity of bambuterol in low dose tablets.

In this study, a new electrogenerated chemiluminescence (ECL) reaction is presented through an oxidative-reductive pathway for amisulpride (AMS) as a new coreactant and Ru(bpy)32+ luminophore for the first time. The unique chemical structure of AMS through the presence of electroactive tertiary amino group in combination with the presence bulky electron donating group attached to α‑carbon of its amino group demonstrates the dramatic increase in ECL intensity of luminophore. Upon electrochemical oxidation of both the AMS and Ru(bpy)32+, the electrogenerated AMS+ undergoes spontaneous deprotonation to produce strong reductant that is reacted with electrogenerated Ru(bpy)33+ for excited state production. The developed method presented highly sensitive, selective, rapid, simple and cost-effective ECL approach for AMS detection. Under optimized parameters, the ECL-concentration plot showed a good linear relationship between ECL intensity and AMS concentrations in presence of 1.0 mM Ru(bpy)32+ over the concentration range of (5.0 × 10−10–2.0 × 10−7 M) with a lower detection limit of 7.6 × 10−9 M and a lower quantification limit of 2.51 × 10−8 M. The developed ECL method is successfully utilized for the determination of AMS in Amipride tablets and real human plasma.

Chemiluminescence (CL) is a light-emitting phenomenon as a result of chemical reactions. Luminol and lucigenin are typical CL luminophores, and hydrogen peroxide is typical coreactant. It is an important analytical technique because of its inherent features, such as high sensitivity, wide dynamic range, fast detection, simple equipment, and low instrumentation costs because no external light source or optics is needed. It has been extensively used for immunoassays, DNA detection, enzymatic biosensors, forensic bloodstain detection, pharmaceutical analysis, metal ion determination, imaging and so on. To improve performance of CL analysis and broaden the applications of CL, it is of great importance to develop new CL systems. Herein, we present some new CL systems such as artemisinin/luminol, thiourea dioxide/luminol, N-hydroxyphthalimide/luminol, hydroxylamine-O-sulfonic acid/luminol, allantoin/ lucigenin and creatinine/H2O2 systems. We will also demonstrate their applications in forensic bloodstain detection, enzyme detection, metal ions detection, and so on [1-7]. Acknowledgment We are grateful for financial support from the National Key Research and Development Program of China (No. 2016YFA0201300), National Natural Science Foundation of China (Nos. 21874126,21675148), the Chinese Academy of Sciences (CAS)-the Academy of Sciences for the Developing World (TWAS), President’s Fellowship Program, and the CAS President's International Fellowship Initiative (PIFI) project. References 1. Wenyue Gao, Chao Wang, Kateryna Muzyka, Shimeles Addisu Kitte, Jianping Li, Wei Zhang and Guobao Xu*. Artemisinin-luminol chemiluminescence for forensic bloodstain detection using smart phone as detector. Chem., 2017, 89 (11), 6160–6165. 2. Wenyue Gao, Wenjing Qi, Jianping Lai, Liming Qi, Saadat Majeed and Guobao Xu*. Thiourea dioxide as unique eco-friendly coreactant of luminol chemiluminescence for sensitive detection of luminol, thiourea dioxide, and cobalt ions. Chem. Commun., 2015, 51(9), 1620–1623. 3. Muhammad Saqib, Liming Qi, Pan Hui, Anaclet Nsabimana, Mohamed Ibrahim Halawa, Wei Zhang,* Guobao Xu*. Development of luminol-N-hydroxyphthalimide chemiluminescence system for highly selective and sensitive detection of superoxide dismutase, uric acid and Co2+. Biosens. Bioelectron., 2018, 99, 519-524. 4. Muhammad Saqib, Baohua Lou, Mohamed Ibrahim Halawa, Shimeles Addisu Kitte, Zhongyuan Liu, Guobao Xu* Chemiluminescence of lucigenin-allantoin and its application for the detection of allantoin. Chem., 2017, 89(3), 1863-1869. 5. Muhammad Saqib, Wenyue Gao, Jianping Lai, Liming Qi, Saadat Majeed, Muhammad Rehan Hasan Shah Gilani, Guobao Xu*. Hydroxylamine-O-sulfonic acid as an efficient coreactant of luminol chemiluminescence for selective and sensitive detection. Chem. Commun., 2015, 51, 6536–6539. 6. Yixiang Lan, Fan Yuan, Tadesse Haile Fereja, Chao Wang, Baohua Lou*, Jianping Li*, and Guobao Xu*. Chemiluminescence of Lucigenin/Riboflavin and Its Application for Selective and Sensitive Dopamine Detection. Anal. Chem., 2019, 91(3), 2135-2139. 7. Saima Hanif, Peter John*, Wenyue Gao, Muhammad Saqib, Liming Qi, Guobao Xu*. Chemiluminescence of creatinine/H2O2/Co2+ and its application for selective creatinine detection. Biosens. Bioelectron., 2016, 75, 347-351.

The authors describe the first chemiluminescence (CL) based method for determination of pyridoxal 5′-phosphate (PLP). PLP is found to generate intense CL with lucigenin higher than that of the conventional lucigenin-H2O2 system by a factor of about 9.0. This new finding is used to be in a detection method for PLP via flow injection analysis (FIA). Response is linear in the 50 nM to 200 μM PLP concentration range with a correlation coefficient of 0.998, and the detection limit (at an S/N of 3) is 6.9 nM. The assay is highly selective over various amino acids, vitamins, sugars, coenzymes and metal ions cofactors. It exhibits advantages over the commonly employed HPLC methods in that it is rapid, more economic, eco-friendly and high throughput FIA detection of PLP without the need for toxic derivatization reagents, organic solvents, and HPLC instrumentation. The method was successfully applied to the determination of PLP in (spiked) human blood samples with recoveries in the range from 96.2–101.6% with % RSD

A highly sensitive, simple and rapid spectrofluorimetric method was developed for the determination of Amlexanox (AMX) in its bioadhesive buccal tablets. The proposed method is based on measuring the native fluorescence of the methanolic solution of AMX at 400 nm after excitation at 242 nm in 0.2 M borate buffer (pH 10) and 0.5% w/v sodium dodecyl sulfate (SDS) solution. The interaction of AMX with SDS was studied, and the enhanced fluorescence intensity was exploited to develop an assay method for the determination of AMX. The relative fluorescence intensity-concentration plot was rectilinear over the range 5.0-80.0 ng/mL, with a lower detection limit of 0.57 ng/mL and a lower quantification limit of 1.74 ng/mL. The proposed method was successfully applied to the analysis of AMX in its commercial tablets. Moreover, content uniformity testing was conducted by applying official USP guidelines. Statistical evaluation and comparison of the data obtained using the proposed and comparison methods revealed good accuracy and precision for the proposed method.

N-hydroxyphthalimide (NHPI), a well known reagent in organic synthesis and biochemical applications, has been developed as a stable and efficient chemiluminescence coreactant for the first time. It reacts with luminol much faster than N-hydroxysuccinimide, eliminating the need of a prereaction coil used in N-hydroxysuccinimide system. Without using prereaction coil, the chemiluminescence peak intensities of luminol-NHPI system are about 102 and 26 times greater than that of luminol-N-hydroxysuccinimide system and classical luminol-hydrogen peroxide system, respectively. The luminol-NHPI system achieves the highly sensitive detection of luminol (LOD = 70pM) and NHPI (LOD = 910nM). Based on their excellent quenching efficiencies, superoxide dismutase and uric acid are sensitively detected with LODs of 3ng/mL and 10pM, respectively. Co

Two accurate analytical methods were developed for the resolution and analysis of a binary mixture of acemetacin (ACE) and chlorzoxazone (CLZ). The first method depends on chromatographic separation of ACE and CLZ using a Shimadzu VP-ODS column. Mobile phase containing 0.075 M sodium dodecyl sulphate, 0.3% triethylamine, 10% n-propanol in 0.02 M orthophosphoric acid of pH 5.5 was pumped at a flow rate of 1 mL/min. with UV detection at 210 nm. The method was further extended to the determination of acemetacin (ACE) and chlorzoxazone (CLZ) in spiked human plasma without prior extraction. For the second method, it depends on measuring the amplitudes of the first derivative spectra at 281.75 nm for ACE and 242.53 nm for CLZ.

A highly sensitive, simple and rapid spectrofluorimetric method was developed for the determination of amisulpride (AMS) and bumidazone (BUM) in tablet form. The proposed method is based on measuring the native fluorescence of the studied drugs in methanol at 360 and 344 nm after excitation at 276 and 232 nm for AMS and BUM, respectively. The fluorescence–concentration plots were rectilinear over the ranges of 5.0–60.0 ng/mL for AMS and 0.5–5.0 µg/mL for BUM. The lower detection limits were 0.70 ng/mL and 0.06 µg/mL, and the lower quantification limits were 2.0 ng/mL and 0.18 µg/mL for AMS and BUM, respectively. The method was successfully applied for the analysis of AMS and BUM in commercial tablets. Statistical evaluation and comparison of the data obtained using the proposed and comparison methods revealed good accuracy and precision for the proposed method. Copyright © 2014 John Wiley & Sons, Ltd.

Two simple, sensitive and accurate spectrophotometric methods have been developed for the determination of bumadizone in bulk drug and its tablets. Both methods based on the oxidative coupling reaction with 3-methyl-2-benzothiazolinone hydrazone hydrochloride (MBTH) and measuring the absorbance of the developed colors by direct or kinetic spectrophotometric method. Upon treatment of a mixture of the chromogenic reagent and drug with cerium (IV) ammonium sulfate (method I) or ferric chloride (method I), a red or violet color was developed immediately or after 30 minutes measurable at 557 nm for method I or II, respectively. The absorbance-concentration plots were rectilinear over the ranges of 1-10 μg/mL (r = 0.9999) for method I and 2-16 μg/mL (r = 0.9998) for method II. The detection limits were 0.15 and 0.27 μg/mL & the quantitation limits were 0.46 and 0.84 μg/mL for methods I and II, respectively. Different experimental parameters affecting the development and stability of the reactions products were studied and optimized. The proposed methods were applied successfully to the determination of bumadizone in its tablets, and the results obtained were in good agreement with those obtained using a comparison method.

Zr(IV) can form phosphate and Zr(IV) (–PO32−–Zr4+–) complex owing to the high affinity between Zr(IV) with phosphate. Zr(IV) can induce the aggregation of gold nanoparticles (AuNPs), while adenosine triphosphate(ATP) can prevent Zr(IV)-induced aggregation of AuNPs. Herein, a visual and plasmon resonance absorption (PRA)sensor for ATP have been developed using AuNPs based on the high affinity between Zr(IV)with ATP. AuNPs get aggregated in the presence of certain concentrations of Zr(IV). After the addition of ATP, ATP reacts with Zr(IV) and prevents AuNPs from aggregation, enabling the detection of ATP. Because of the fast interaction of ATP with Zr(IV), ATP can be detected with a detection limit of 0.5 μM within 2 min by the naked eye. Moreover, ATP can be detected by the PRA technique with higher sensitivity. The A520nm/A650nm values in PRA spectra increase linearly with the concentrations of ATP from 0.1 μM to 15 μM (r = 0.9945) with a detection limit of 28 nM. The proposed visual and PRA sensor exhibit good selectivity against adenosine, adenosine monophosphate, guanosine triphosphate, cytidine triphosphate and uridine triphosphate. The recoveries for the analysis of ATP in synthetic samples range from 95.3% to 102.0%. Therefore, the proposed novel sensor for ATP is promising for real-time or on-site detection of ATP.