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In this work, electromembrane extraction (EME) was used for the first time to separate aconitine (AC), mesaconitine (Mes-AC) and hypaconitine (Hyp-AC) from biological samples and Chinese herbal medicines. Efficient EME of polar and high molecular weight aconitine alkaloids from different sample matrices was achieved with the solvent of 1-ethyl-2-nitrobenzene (ENB). Under the optimal EME conditions, EME provided recoveries for all targets in the range of 72%-74 %, 85%-103 % and 92%-94 % for whole blood, urine and aqueous samples. The proposed EME systems combined with LC-MS/MS and HPLC-UV were evaluated using different sample matrices, and the methods displayed satisfactory analytical characteristic including negligible matrix effect. The LOD and LOQ of AC, Mes-AC, and Hyp-AC by EME-LC-MS/MS were in the range of 0.002-0.068 ng/mL and 0.005-0.228 ng/mL respectively. The LOD and LOQ of AC, Mes-AC, and Hyp-AC by EME-HPLC-UV were in the range of 0.06-0.26 μg/mL and 0.20-0.86 μg/mL, respectively. The coefficient of determination, R 2 -value was ≥0.9926 for all cases, and the accuracy in the linear ranges was in the range of 91%-111 %. Finally, the method was successfully applied for the qualitative and quantitative analysis of AC and Mes-AC in the whole blood and herbal medicine dreg samples from an actual forensic case, and poisoning by aconitum alkaloids was identified as the cause of death. Therefore, we believe that EME could be a powerful tool to identify poisoning, and EME has great potential for efficient separation of polar and high molecular weight substances. These are of great importance in the fields of but not limited to forensic science, Traditional Chinese Medicine and clinics., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Kynurenic acid (KA) is an active metabolite of tryptophan with notable biological effects, such as antioxidant, neuroprotective, and anti-inflammatory properties. It often undergoes changes of the concentration in biological fluids in chronic diseases. Thus, detecting KA is of great importance for diagnosing inflammatory and neurodegenerative conditions, monitoring disease progression, and assessing responses to pharmacological treatment. This study aimed to design a tailored, flexible platform for sensitive and direct electrochemical detection of KA in biological fluids. Carbon-based electrodes were custom-printed in the lab using specialized inks and flexible substrates. The working electrodes were further functionalized with graphene oxide and subsequently electrochemically reduced to increase the sensitivity toward the analyte. An optimized differential pulse voltammetry protocol was developed for KA detection. The elaborated platform was firstly characterized and then evaluated regarding the analytical performances. It showed a good limit of detection (3 nM and demonstrated the capability to detect KA across a broad concentration range (0.01-500 μM). Finally, the elaborated flexible platform, was succesfully applied for KA determination in serum and saliva samples, in comparison with an optimized HPLC-UV method. The developed platform is the first example of in-lab printed flexible platform reported in literature so far for KA detection. It is also the first study reported in the literature of detection of KA in raw saliva collected from 10 subjects. The sensitivity towards the target analyte, coupled with the adaptability and portability, showcases the potential of this platform for thus illustrating great potential for further development of wearable sensors and biomedical applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

The repeatable immobilization of molecular recognition elements onto particle surfaces has a strong impact on the outcomes of affinity-based assays. In this work, an automatic method for the immobilization of immunoglobulin G (IgG) onto protein A-Sepharose microbeads was established through the flow programming features of the portable lab-on-valve platform using micro-bead injection spectroscopy. The reproducible packing of protein A-microbeads between two optic fibers was feasible, allowing on-column probing of IgG retention. The automation of solutions handling and the precise control of time of IgG interaction with the beads rendered repeatable immobilization cycles, within a short timeframe (<2 min). The proposed method featured the preparation of disposable immunosorbents for downstream analytical applications, such as immunosensing or microenrichment of target analytes. In-situ quantification of IgG@protein A-microbeads was carried out using a horseradish peroxidase-labeled detection IgG. The colorimetric oxidation of 3,3′,5,5′-tetramethylbenzidine was monitored on-column. Quantitation of mouse and human IgG immobilized@protein A-microbeads was achieved for loading masses between 0.1 and 0.4 μg per ca. 5.5 mg of sorbent. The implemented detection strategy allowed the quantification of human IgG in certified human serum (ERM®- DA470k/IFCC) and spiked saliva, yielding recoveries of 102–108% and requiring minimal volume (1–15 μL) from serum and saliva. Image 1 • Automatic functionalization of disposable microbeads for immunoaffinity assays. • Fast (<2 min) and repeatable immunoglobulin G immobilization in miniaturized set-up. • In-situ probing of functionalization through on-column colorimetric measurements. • Selective immunoglobulin G quantification in saliva and serum samples. [ABSTRACT FROM AUTHOR]

Abstract In this work, we propose an innovative high throughput (HT) apparatus using the bar adsorptive microextraction (BAμE) technique, which enables the simultaneous enrichment of up to 100 samples. This novel configuration was combined with microliquid desorption and high-performance liquid chromatography-diode array detection to monitor trace levels of eight benzodiazepines (diazepam, prazepam, bromazepam, oxazepam, lorazepam, alprazolam, temazepam and loflazepate) in biological samples. The proposed methodology was fully developed, optimized and validated, resulting in suitable intraday and interday precision (RSD ≤ 15%), with recovery yields ranging from 33.0% to 104.5%. The lower limits of quantification were between 20.0 and 100.0 µg L−1, using 1.0 mL of urine and 0.5 mL of plasma or serum samples. The application of the proposed methodology to real matrices resulted in average sample preparation time of around 2 min per sample, demonstrating that it is user-friendly, cost-effective and a rapid decision-making tool, whenever large number of samples are involved. Graphical abstract fx1 Highlights • An alternative approach for monitoring benzodiazepines in biological fluids. • A new analytical cycle that can perform up to 100 simultaneous microextractions. • Sample preparation time of about 2 min per sample. • A methodology optimized, validated and applied in urine, plasma and serum samples. [ABSTRACT FROM AUTHOR]

Abstract Herein, a robust and homogeneous porous poly(3,4-ethylenedioxythiophene)/graphene (PEDOT/graphene) thin film surface-assisted laser desorption/ionization (SALDI) functional platform was prepared through a rapid and facile in-situ photopolymerization method. The graphene-embedded PEDOT skeleton well circumvented the aggregation-related problems in the traditional carbon-based SALDI method which combined with time-of-flight mass spectrometer (TOF MS). As a result, the reproducibility and quantitative capacity of the SALDI platform were significantly improved. Furthermore, the highly efficient adsorption performance of the PEDOT/graphene thin film was demonstrated in terms of in vitro and in vivo solid-phase microextraction (SPME) extraction. It showed that porous morphology with abundant graphene doping favored the adsorption and enrichment of target analytes. Owing to the excellent adsorption capability of the PEDOT/graphene thin film and the inherent strong laser absorption ability of graphene, expected SALDI effect (3–13 times higher than the commercial nanomaterial-assisted LDI plate) and quantitative analysis (linear range 0.5–100 μg L−1) of the PEDOT/graphene functional surfaces were achieved. As for the real-world applications, we deployed the PEDOT/graphene thin film SALDI platform for the analysis of five estrogens in biological samples at microliter-volume level, without tedious sample preparation procedures. Satisfactory recoveries ranging from 60.6% to 99.0% were obtained. The present study suggested that the graphene-embedded PEDOT skeleton with porous morphology would be developed as promising coating for the adsorption of analytes of interest. Additionally, the combination of PEDOT with graphene not only expanded the application fields of PEDOT, but also offered an efficient strategy for preparing homogeneous functional surfaces to realize the quantitative analysis in SALDI method. Graphical abstract fx1 Highlights • Robust and homogeneous porous PEDOT/graphene based SALDI platform was prepared via an in-situ photopolymerization method. • The graphene-embedded PEDOT skeleton well circumvented the aggregation-related problems. • The high-efficiency adsorption performance of the PEDOT/graphene thin film was demonstrated by in vitro and in vivo SPME. • The analyses of estrogens in biosamples at μL-volume level without tedious sample preparation procedures were realized. [ABSTRACT FROM AUTHOR]

Solid phase extraction (SPE) and solid phase microextraction (SPME) are among the most significant sample clean-up and pretreatment techniques, which have attracted a considerable interest in the pre-concentration and determination of a wide variety of analytes in biological, pharmaceutical, environmental, industrial and food samples. The purpose of this review article is to focus on the latest advancements and applications of SPE and SPME methods based on new nanomaterial adsorbents for separation, concentration and determination of different analytes in biological media. To this end, some sorbents such as metal organic frameworks, molecularly/ion-imprinted polymers, carbon nanotubes, magnetic nanoparticles, graphene and graphene oxide, and metallic nanoparticles are discussed here. [ABSTRACT FROM AUTHOR]

In the present study, procaterol hydrochloride (ProH) was successfully electropolymerized onto a glass carbon electrode (GCE) with simply cyclic voltammetry scans to construct a poly(procaterol hydrochloride) (p-ProH) membrane modified electrode. Compared with the bare GCE, much higher oxidation peak current responses and better peak potentials separation could be obtained for the simultaneous oxidation of dopamine (DA) and uric acid (UA), owning to the excellent electrocatalytic ability of the p-ProH membrane. And it's based on that a square wave voltammetry (SWV) method was developed to selective and simultaneous measurement of DA and UA. Under the optimum conditions, the linear dependence of oxidation peak current on analyte concentrations were found to be 1.0–100 μmol/L and 2–100 μmol/L, giving detection limits of 0.3 μmol/L and 0.5 μmol/L for DA and UA, separately. The as prepared modified electrode shows simplicity in construction with the merits of good reproducibility, high stability, passable selectivity and nice sensitivity. Finally, the proposed p-ProH membrane modified electrode was successfully devoted to the detection of DA and UA in biological fluids such as human serum and urine with acceptable results. [ABSTRACT FROM AUTHOR]

Monitoring of amphetamine-type stimulant (ATS) confronts clinical labs with a high number of samples involving a variety of biological matrices. Liquid chromatography-tandem mass spectrometry (LC-MS/MS), routinely used for confirmation of ATS abuse, requires of laborious and matrix-dependent sample treatment methods, this increasing analysis time and cost. In this work, a universal and single-step sample treatment, based on supramolecular solvents (SUPRAS), was proposed for simplifying ATS confirmation in seven biological matrices. The SUPRAS was synthesized in situ in the sample (900 µL of basified oral fluid, urine, serum, sweat or breast milk or 50 mg of digested hair or fingernails) by the addition of hexanol (200 µL) and tetrahydrofuran (900 µL). The mixture was vortex-shaken and centrifuged and the SUPRAS extract was subsequently analyzed by positive ion mode electrospray LC-MS/MS. The method was fully validated for amphetamine (AMP), methamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA), N-ethyl-3,4-methylenedioxyamphetamine (MDEA) and N-methyl-3,4-methylenedioxyamphetamine (MDMA). Maximum ion suppression or enhancement was 9% and 7%, respectively, and extraction recoveries (87–111%) and within- (0.1–6.7%) and between-day (0.3–9.7%) CVs were all within required values. The lower limits of quantification (LLOQ) for biological fluids (5 ng/mL), and hair and fingernails (100 ng/g) were all well below the cut-offs established by worldwide organizations. Confirmation of MDA was carried out in five urine samples that tested positive for ATS by immunoassay. The SUPRAS-LC-MS/MS methodology succeeded in developing a hitherto unexplored and universal tool for quantifying ATS in a comprehensive pool of biological matrices of interest in forensic and clinical samples. [ABSTRACT FROM AUTHOR]

In the present work, for the first time, a new portable setup was designed, developed and presented for the extraction of methadone, as a basic drug model from biological fluid samples using a low-voltage electrically stimulated stir membrane liquid–liquid microextraction technique (LV-ESSM-LLME), followed by high-performance liquid chromatography with ultraviolet detection. This new approach combines the advantages of stir membrane liquid–liquid microextraction and electrokinetic migration in the same unit under soft electrochemical conditions in a portable device, allowing for the isolation and preconcentration of the target analyte in a simple and efficient manner under three-phase mode. To investigate the influence of external stirring and the application of electrical potential as the driving force, a comparative study of all variables involved in the extraction process was carried out using the low-voltage electromembrane extraction (LV-EME) and LV-ESSM-LLME methods. Under soft electrokinetic migration conditions, methadone was transported from an acidic sample solution (pH 4.0), through the NPOE immobilized in the pores of the porous polypropylene sheet membrane, and into 25 µL of 10 mmol L −1 HCl acceptor solution with a stirring rate of 1000 rpm and 700 rpm after 15 min and 20 min for LV-ESSM-LLME and LV-EME, respectively. Under the optimized conditions, preconcentration factors in the range of 17–24 and 21.5–29 for LV-EME and LV-ESSM-LLME, respectively, were considered, and satisfactory repeatability (4.5<[RSD]<7.5) was obtained in different matrices. The obtained relative recoveries of the target analyte were in the range of 87–94% and 93–101% for LV-EME and LV-ESSM-LLME, respectively, which indicated the excellent capability of the developed methods to extract methadone from complex matrices. [ABSTRACT FROM AUTHOR]

Nowadays, a deep eutectic solvent (DES) has recently been considered as a green ion liquid analogue. In this study, a new compound of DES has been synthesized as an extraction solvent in air assistedemulsification liquid–liquid microextraction method (DES-AAELLME) for preconcentration and extraction of methadone followed by gas chromatographyflame ionization detector (GC–FID). To obtain an efficient water-miscible deep eutectic solvent, choline chloride (ch-cl) and 5,6,7,8-Tetrahydro-5,5,8,8-tetramethylnaphthalen-2-ol (TNO) were mixed at a molar ratio of 1:2 and tetrahydrofuran (THF) was used as a demulsifier solvent into homogeneous solution for providing a turbid state. The solution was rapidly sucked up and injected 10 times using a 10-mL glass syringe to enhance the turbidity of solution and disperse the aggregated DES droplets into aqueous phase. Some important parameters affecting extraction recovery were investigated. Under optimum conditions, the calibration curve was linear in the concentration range from 2 to 8000 µg L −1 . The limit of detection and the limit of quantification were found 0.7 µg L −1 and 2.3 µg L −1 respectively with preconcentration factor of 270. The precision, as the relative standard deviation (RSD) (n=6), was <6% respectively. This method was successfully applied to determine methadone in water and biological samples with an appropriate recovery about 98.4–101.2%. [ABSTRACT FROM AUTHOR]

Different causes can trigger imbalances on homeostatic mechanisms between intracellular and extracellular compartments resulting in abnormal blood potassium concentrations (hypo or hyperkalemia). This can lead to serious consequences, even a life-threatening situation. Early diagnosis, treatment and follow-up are essential to minimize critical impacts in patients. Bedside determination of blood potassium is not accessible in all health care centers or in all emergency departments and far less common in this kind of centers in emerging countries. We have therefore proposed a portable, economic and long-lifetime potentiometric point-of-care (POC) analytical microsystem to deal with this question. It is a continuous flow microfluidic platform, made of cyclic olefin copolymer (COC), which combines microfluidics and a detection system based on the potentiometric technique containing a potassium selective electrode with a novel composition of polymeric membrane, which improves lifetime. Its size is smaller than a credit card and shows a linear range of Nernst calibration equation from 1 to 26 mM K+, a detection limit of 0.16 mM K+, a satisfactory repeatability and reproducibility, and an analysis frequency of 20 samples h−1, requiring only 25 μL as sample volume. Moreover, lifetime is as long as 9 months by intensive use. All these features comply with medical requirements. Human serum samples were analyzed with the developed device and the obtained results were compared with those provided by two methods: ICP-OES and another using ion selective electrodes. No significant differences were observed, demonstrating the suitability of the developed POC microanalyzer for bedside health applications. [Display omitted] • Potentiometric analytical microsystem as Point-of-Care equipment for bedside potassium monitoring. • Improved Ion Selective Electrode polymeric membrane to lengthen POC microsystem lifetime. • Working range covering physiological and pathological serum/plasma potassium levels. • Human serum samples successfully analyzed. [ABSTRACT FROM AUTHOR]

Tenofovir (TNF) is an antiviral medicine that is utilized to treat the human immunodeficiency virus (HIV). However, its level must be controlled in the human body and environment at the risk of causing kidney and liver problems. Therefore, determining TNF concentration in real samples with more advanced, inexpensive, and accurate sensing systems is essential. In this work, a novel electrochemical nanosensor for TNF determination based on molecularly imprinted polymer (MIP) on the screen-printed electrode modified with functionalized multi-walled carbon nanotubes, graphite carbon nitride, and platinum nanoparticles (MIP-Pt@g-C 3 N 4 /F-MWCNT/SPE) was constructed through the electro-polymerization approach. The molecularly imprinted polymers were prepared on the electrode surface with TNF as the template molecule and 2-aminophenol (2-AP) as the functional monomer. Moreover, factors that affect sensor response were optimized. Pt@g-C 3 N 4 /F-MWCNT nanocomposite had an excellent synergistic effect on MIP, allowing rapid and specific identification of the test substance. The results demonstrated that the electro-polymerization of 2-AP supplies large amounts of functional groups for the binding of the template molecules, which remarkably enhances the sensitivity and specific surface area of the MIP sensor. This surface enlargement increased the analyte accessibility to imprinted molecular cavities. Under optimum conditions, the oxidation peak current had a linear relationship with TNF concentration ranging from 0.005 to 0.69 μM with a low detection limit of 0.0030 μM (S/N = 3). The results demonstrated that the designed MIP sensor possesses acceptable sensitivity, repeatability, and reproducibility toward TNF determination. Moreover, the developed sensor was applied to biological and water samples to determine TNF, and satisfactory recovery results of 95.6–104.8% were obtained (RSD less than 10.0%). We confirm that combining as-synthesized nanocomposite Pt@g-C 3 N 4 /F-MWCNT with MIP improves the limitations of MIP-based nanosensors. The proposed electrode is also compatible with portable potentiostats, allowing on-site measurements and showing tremendous promise as a point-of-care (POC) diagnostic platform. [Display omitted] • Tenofovir sensing material of the molecularly imprinted polymer was synthesized. • A design of developed sensor of MIP-Pt@g-C 3 N 4 /F-MWCNT was introduced to detect Tenofovir. • The MIP-based sensor offered a linear response across a wide dynamic range from 0.005 to 0.69 μM. • The developed sensor's selectivity, accuracy, and reliability were well characterized in real samples. [ABSTRACT FROM AUTHOR]

Detecting proteins via surface assisted laser desorption/ionization mass spectrometry (SALDI-MS) method is still highly challenging, and only few examples of nanomaterials have been demonstrated to perform such detection so far. In this study, carbon nanowalls (CNWs), vertically aligned graphene sheet-based materials, presenting specific morphology, dimensions, and boron doping levels have shown improved performances for both qualitative and quantitative detection of Cytochrome C under optimized experimental conditions. Boron doped carbon nanowalls (B-CNWs) with a [B]/[C] ratio of 5000 ppm and growing time of 4 h have shown the best performance in terms of signal intensity and reliability. Then, the detection of ricin, a ribosomal-inhibiting protein (RIP) classified as category B bioterrorism agent by CDC (Centre of Disease and Control and Prevention), was performed. For the first time, direct SALDI-MS detection of ricin B chain was reported without tedious sample preparation steps or database interrogation, and results were obtained within few minutes and a limit of detection (LOD) of 0.5 pmol/μl was obtained. Thanks to the introduction of galactosamine residues on B–CNW, we were able to selectively detect ricin B chain protein in complex media such as serum and soft drinks with enhanced signal intensity. B-CNWs are not toxic and are adaptable to any commercial MALDI-TOF mass spectrometer, showing their great potential as SALDI based materials. [Display omitted] • Boron-doped carbon nanowalls, new nanomaterials for the direct detection of proteins by SALDI-MS. • Straightforward and fast method (few minutes) for mass spectrometry detection of Ricin B chain with good sensitivity. • Detection of Ricin B chain in complex media: soft drinks and serum. • On-plate enrichment via galactosamine residues grafting and enhancing the MS signal intensity. [ABSTRACT FROM AUTHOR]

A simple and reliable method for preparing a selective dopamine (DA) sensor based on a molecularly imprinted polymer of ethacridine was proposed. The molecularly imprinted polymer electrode was prepared through electrodepositing polyethacridine-dopamine film on the glassy carbon electrode and then removing DA from the film via chemical induced elution. The molecular imprinted sensor was tested by cyclic voltammetry as well as by differential pulse voltammetry (DPV) to verify the changes in oxidative currents of DA. In optimized DPV conditions the oxidation peak current was well-proportional to the concentration of DA in the range from 2.0×10 −8 M up to 1×10 −6 M. The limit of detection (3σ) of DA was found to be as low as 4.4 nM, by the proposed sensor that could be considered a sensitive marker of DA depletion in Parkinson's disease. Good reproducibility with relative standard deviation of 1.4% and long term stability within two weeks were also observed. The modified sensor was validated for the analysis of DA in deproteinized human serum samples using differential pulse voltammetric technique. [ABSTRACT FROM AUTHOR]

A hydrophobic surface modified iron oxide magnetic nano-sorbent was successfully synthesized, characterized and utilized for highly effective removal and recovery of Berberine (Brb) by Ultrasound Assisted Dispersive Magnetic Solid Phase Extraction (UADM-SPE). Fabrication of p-Naphtholbenzein-coated magnetic nanoparticles (PNB-MNPs) was certified by characteristic analyses such as: Fourier transform infrared spectroscopy (FT-IR), X-ray Diffraction (XRD), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The characterized PNB-MNPs were utilized to develop a UADM-SPE method for Brb, a well-known isoquinoline alkaloid with a highlighted chemical skeleton for designing selective and powerful bioactive molecules. Affecting parameters on the extraction of Brb were optimized through an orthogonal rotatable central composite design (CCD). The optimum condition is obtained when the variables are set to: pH=4, amount of MNPs=20 mg, sample volume=30 ml, sonication time=1 min at room temperature, and desorbing solvent=500 µL of methanol. Under the mentioned condition, an extraction recovery of 98.2%, with relative standard deviation of 3.7%, was obtained via five replicated measurements on a 0.1 mg L −1 Brb standard solution. Finally, the method was successfully applied for determination of Brb in human plasma and urine samples. Regarding the method calibration graphs in plasma and urine matrices, spiked in the range of 0.01–200.00 µg L −1 , pre-concentration factors of 134 and 122, method detection limit (MDL) of 0.17 and 0.19 µg L −1 , and lower limit of quantification of 0.57 and 0.63 µg L −1 were obtained for plasma and urine samples, respectively. The method exhibits good potentials to be a fast, efficient and reliable method for determination of Brb in human biological samples. [ABSTRACT FROM AUTHOR]

A novel magnetic graphene oxide nanocomposite was synthesized by one-step coprecipitation method and characterized by transmission electron microscopy, X-ray photoelectron spectroscopy and vibrating sample magnetometer. The nanocomposite beard many intriguing properties, including chemical stability, high adsorption capacity, and superparamagnetic. These properties evoked great interest and desire of its exploration in magnetic solid-phase extraction of heavy metal ions from complex samples. Several parameters effecting the analytical performance, such as the sample pH, amounts of adsorbent, sample volumes, elution volumes, and coexisting ions, had been investigated in detail. The adsorbed metal ions were easy eluted by controlling the pH condition and the materials could be reused more than 20 times. Under the optimized conditions, the limits of detection were 0.016, 0.046, 0.395, 0.038, 0.157 μg L −1 for Co 2+ , Ni 2+ , Cu 2+ , Cd 2+ , and Pb 2+ , respectively. The intra-day relative standard deviations ( n =5) were in the range of 1.8–5.5% at 10 μg L −1 . The proposed method was successfully applied to biological sample analysis and got excellent recoveries in the range of 81–113% even the matrix was complex. [ABSTRACT FROM AUTHOR]

An approach, based on ion mobility spectrometry (IMS) has been developed for the control of cocaine in air of the breathing zone of operators, in laboratory surfaces and in nasal mucus of employees to evaluate cocaine exposure in a forensic laboratory. The analytical methodology has been validated in terms of accuracy, precision and limits of detection and results obtained were statistically comparable with those obtained by liquid chromatography. Cocaine concentration in laboratory air increases from 100±35 ng m-3 of a normal day to 10,000 ng m-3 during the manipulation of cocaine seizures. The occupational exposure limit (OEL) for cocaine has not been established which difficult the evaluation of the health effects of continuous exposition to very small doses of cocaine. Cocaine was also found in almost all the analyzed sample surfaces and also was found in nasal mucus of the police officers that were present during the manipulation of cocaine seizures without using a face mask. In summary, cocaine concentrations could present a health hazard to the employees and therefore warrants remediation and some modifications of the manipulation operations have been proposed. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) has showed great potential to use as an adsorbent in sample preparation procedures. In this research, GO was used as an effective adsorbent in a simple GO-based dispersive micro-solid phase extraction (GO-D-µ-SPE) method for isolation and preconcentration of nicotine prior to gas chromatography-flame ionization detection (GC-FID). The prepared GO was characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscope (SEM), thermogravimetric analysis/differential thermal analysis (TGA/DTA), and ultraviolet-visible (UV-vis) absorption spectroscopy techniques. Various experimental parameters affecting the extraction recovery, including the amount of GO, extraction time, pH of the sample solution, salt concentration, and desorption conditions were investigated and optimized. Under the optimized conditions, a linear response was obtained in the concentration range of 5-2000 ng mL-1 with a determination coefficient of 0.9987. The limit of detection (LOD) of the method at a signal to noise ratio of 3 was 1.5 ng mL-1. The linearity was in the concentration range of 5-2000 ng mL-1 with a determination coefficient of 0.9987. Intraday and inter-day precisions were obtained equal to 2.7% and 5.2%, respectively. The method was successfully applied to the nicotine analysis in biological and water samples with the recoveries in the range of 88.7-109.7%. [ABSTRACT FROM AUTHOR]

Abstract: A method is developed for the determination of trace mercury in biological samples using photo chemical vapor generation (PVG) and isotope dilution inductively coupled plasma mass spectrometry (ID ICPMS) detection. Biological tissues were solubilized in formic acid. Subsequently, the sample solutions were exposed to an ultraviolet (UV) source for the reduction of mercury into vapor species prior to ICPMS measurements. The formic acid served not only as a tissue solubilizer in the sample preparation procedure, but also as a photochemical reductant for mercury in the PVG process. The problem arising from the opaque formic acid digested solution was efficiently solved by using ID method. The optimum conditions for sample treatment and PVG were investigated. A limit of detection (LOD) of 0.5pgg-1, based on an external calibration, provided 350-fold improvement over that obtained by utilizing conventional pneumatic nebulization sample introduction. Method validation was demonstrated by the determination of total mercury in several biological tissue certified reference materials (CRMs). The results were in good agreement with the certified values. [Copyright &y& Elsevier]

Nitric oxide (NO) acts as an important regulator and mediator in numerous processes of biological systems. In this work, the analytical potential of a novel near-infrared (NIR, >600nm) BODIPY-based fluorescent probe for NO, 8-(3,4-diaminophenyl)-4,4-difluoro-4-bora-3a,4a-diaza-di(1,2-dihydro) naphtho[b, g]s-indacene (DANPBO-H) has been evaluated in high performance liquid chromatography (HPLC). In 25mM pH 6.50 borate buffer, DANPBO-H reacted with NO to give the corresponding triazole, DANPBO-H-T, at 35°C for 20min. DANPBO-H-T was eluted using a mobile phase of methanol/tetrahydrofuran/50mM pH 7.00 H3Cit–NaOH buffer (81:7:12, v/v/v) in 4min on a C8 column and detected with fluorescence detection at excitation and emission wavelengths of 621 and 631nm, respectively. The limit of detection (LOD) (signal-to-noise=3) reached to 5.50×10−10 M. Excellent selectivity was observed against other reactive oxygen/nitrogen species. Various representative biological matrixes including the whole blood and organs of mice, the pangen and radical of rice, human vascular endothelial (ECV-304) cells and mouse macrophage (RAW 264.7) cells were used to verify the feasibility and resistance to interfering effects from complex biological sample matrixes of the developed DANPBO-H-based HPLC method. Compared to the existing derivatization-based HPLC methods for NO, the proposed method eliminates interfering effects from complex biological sample matrixes efficiently owing to the fluorescence detection in the NIR region, and is more advantageous and robust for the sensitive and selective determination of NO in complex biological samples. [ABSTRACT FROM AUTHOR]

Abstract: Two new ion-selective electrodes of the plastic membrane type for the determination of Tolterodine (Tol) were prepared. These electrodes depend on the incorporation of the ion-exchangers of the above mentioned drug with phosphotungestic acid (PTA) or Silicotungestic acid (STA) in a PVC matrix. A comparative study is made between the performance characteristics of electrodes containing ion-exchanger in batch and FIA conditions. The usable concentration range of the electrodes was found to be (1.0×10−5–1.0×10−2 and 5.0×10−5–1.0×10−2 M) in batch and FIA conditions, respectively. The electrodes have nearly the same usable concentration, pH range and exhibited high selectivity toward Tol in the presence of many inorganic cations and can be used in biological fluids such as urine and plasma. The dissolution profile of the investigated drug as well as its assay in pure and pharmaceutical preparations was performed, and the results were relatively accurate and precise as indicated by the recovery values and coefficients of variation. [Copyright &y& Elsevier]

Abstract: An automated, simple and inexpensive double-valve sequential injection analysis (DV-SIA) spectrophotometic method with online liquid–liquid extraction, for the determination of thiocyanate has been developed. The method has been based on the formation of an ion associate between thiocyanate and Astra Phloxine in acidic medium, and the subsequent extraction with amylacetate. The absorbance of the extracted ion associate was measured at 550nm. The calibration function was linear in the range 0.05–0.50mmolL−1 and the regression equation was A =(1.887±0.053) [SCN− mmolL−1]+(0.037±0.014) with a correlation coefficient of 0.995. The precision of the proposed method was evaluated by the relative standard deviation (RSD) values at two concentration levels: 0.20 and 0.50mmolL−1. The obtained results were 1.0 and 2.8%, respectively, for the intra-day precision, and 4.2 and 3.8%, respectively for the inter-day precision. The calculated detection limit was 0.02mmolL−1. The developed method has been successfully applied for determining thiocyanate ions in human saliva samples. [Copyright &y& Elsevier]

Abstract: A rapid and efficient capillary zone electrophoresis (CZE) method with ultraviolet detection has been successfully developed for the determination of puerarin in Xinkeshu capsules and biological samples. The optimal CZE conditions were determined to be 70mM H3BO3–Na2B4O7, pH 9.2, injection time 5s, applied voltage 25kV, working temperature 25°C and detection wavelength 254nm. Under these conditions, a linear range from 17.3 to 138μg/mL with the correlation coefficient of 0.9998 and limit of detection of 34.6ng/mL (S/N =3) for puerarin were obtained. The relative standard deviation of the migration time and peak area of puerarin were 0.23–0.91, 0.43–1.62, 0.10–0.64 and 0.64–1.32% for intra-day and inter-day analyses, respectively. Satisfactory results were obtained for recovery and repeatability. The proposed method was successfully applied to analyze the puerarin content in Xinkeshu capsules and some biological samples with good results. It is suitable for applications in pharmaceutical industries for quality control and in clinical laboratories for therapeutic drug monitoring purposes. [Copyright &y& Elsevier]

Abstract: A sensitive, rapid and efficient method for the extraction of quercetin as well as its determination in honey and biological samples was developed using inverted dispersive liquid–liquid microextraction (IDLLME) and HPLC-UV. The extraction method is based on the application of an extracting solvent lighter than water in the ternary component solvent (aqueous solution: extracting solvent: disperser solvent) system. The extraction parameters such as type and volume of extracting and disperser solvent, pH of sample, stirring rate and extraction time were optimized. Under the optimal conditions (extracting solvent: 100μL 1-octanol; disperser solvent: 300μL acetonitrile; pH of sample: 4.5 and stirring rate: 1000rpm) a linear calibration curve was obtained in the range of 0.5–1000ngmL−1 with R 2 =0.9993 (n =10). The limits of detection and quantification were 0.26 and 0.78ngmL−1, respectively. The extraction recovery was 97% and the preconcentration factor was 243. While the relative standard deviation for 25ngmL−1 was 3.51 (n =5), it was 2.12 (n =5) for 500ngmL−1 of quercetin. The method was successfully applied for the preconcentration and determination of quercetin in honey, urine and plasma samples. [Copyright &y& Elsevier]

Abstract: Carrier-mediated three-phase hollow fiber microextraction combined with high-performance liquid chromatography-ultra violet detection (HPLC-UV) was applied for the extraction and determination of propylthiouracil in biological samples. Propylthiouracil (PTU) was extracted from 7.5mL of the basic solution (the source phase) with pH 12 into an organic phase (n-octanol containing 6% (w/v) of Aliquat 336 as the carrier) impregnated in the pores of a hollow fiber, and finally was back extracted into 24μL of the acidic solution located inside the lumen of the hollow fiber (the receiving phase). The extraction was performed through the gradient of counter ion from the source to the receiving phase. The effects of different variables on the extraction efficiency were studied simultaneously using an experimental design. A half-fractional factorial design was employed for screening to determine the variables significantly affecting the extraction efficiency. Then, the factors with significant effect were optimized using a central composite design (CCD) and the response surface equations were developed. The optimal experimental conditions obtained from this statistical evaluation included: source phase, pH 12; temperature, 25°C; extraction time, 40min; counter ion concentration, 2molL−1 of NaClO4; organic solvent 6% of Aliquat in octanol and without salt addition in the source phase. Under the optimized conditions, the preconcentration factors were between 125 and 198 and also the limit of detections (LODs) ranged from 0.1μgL−1 to 0.4μgL−1 in different biological samples. The calibration curve was linear (r 2 =0.998) in the concentration range of 0.5–1000μgL−1. Finally, the feasibility of the proposed method was successfully confirmed by extraction and determination of PTU in human plasma and urine as well as the bovine milk and meat samples in microgram per liter, and suitable results were obtained (RSDs<6.3%). [Copyright &y& Elsevier]

Abstract: The poly(N-isopropylacrylamide) (PNIPA) gel is a widely studied thermo-responsive material that exhibits discontinuous change in volume when the external temperature is increased. In this paper, PNIPA gel was prepared and applied as a novel polymer coating for fiber-in-tube capillary microextraction of trace Co, Ni and Cd followed by on-line ICP-MS detection. The PNIPA coating was synthesized by using ethylene triethoxysilane (ETEOS) as the cross-linking agent under acidic conditions. This siloxane incorporated PNIPA gel achieves a dramatically rapid response rate when the external temperature is changed. The micro-structure of PNIPA coating was examined by scanning electron micrograph (SEM). Various experimental parameters including pH, temperature, sample flow rate and volume, elution solution and interfering ions affecting the extraction of the target analytes have been carefully investigated and optimized. Under the optimized conditions, the limits of detection were 0.45, 4.6 and 6.9ngL−1 for Co, Ni and Cd, respectively. With a sampling frequency of 13h−1, the relative standard deviations (RSDs) for Co, Ni and Cd were 4.8, 5.1 and 6.4% (C =1μgL−1, n =7), respectively. The proposed method had been successfully applied to the determination of Co, Ni and Cd in human urine. To validate the proposed method, certified reference materials of NIES No. 10-b rice flour and GBW07601 (GSH-1) human hair were analyzed and the determined values were in a good agreement with the certified values. The PNIPA coated fiber-in-tube capillary can be reused for more than 150 times without decreasing the extraction efficiency. [Copyright &y& Elsevier]

Abstract: An extensive survey of the literature published in analytical and pharmaceutical chemistry journals has been conducted and analytical methods which were developed and used for the determination of some of the COX-2 inhibitors, a subclass of non-steroidal anti-inflammatory drugs (NSAIDs) in bulk drugs, formulations, and biological fluids have been reviewed. This review covers the time period from 1999 to present, during which over 140 analytical procedures including chromatographic, spectrometric, electrophoretic and voltammetric techniques were reported. Presented applications concern analysis of coxibs from pharmaceutical formulations and biological samples. [Copyright &y& Elsevier]

Abstract: The simultaneous determination of catecholamines – epinephrine and norepinephrine by square wave voltammetry (SWV) at physiological pH 7.2 is reported using multi-walled carbon nanotubes modified edge plane pyrolytic graphite electrode (MWNT/EPPGE). A broad bump at ∼250mV is appeared for the oxidation of epinephrine (EP) and norepinephrine (NE) at bare EPPGE whereas at MWNT/EPPGE two well-separated peaks at ∼150 and ∼215mV are appeared for the oxidation of EP and NE, respectively. The oxidation peak current of both the neurotransmitters also increased significantly along with the negative shift of peak potentials using MWNT/EPPGE. The oxidation of both compounds occurred in a pH dependent, 2e and 2H+ process and the electrode reaction followed diffusion controlled pathway. Linear calibration curves were obtained for epinephrine and norepinephrine in the range 0.5–100nM with limits of detection 0.15×10−9 and 0.90×10−10 M, respectively. The developed protocol is implemented for the simultaneous determination of epinephrine and norepinephrine in blood plasma and urine samples of smokers as well as in athletes. [Copyright &y& Elsevier]

Abstract: A fast method for mercury extraction from biological samples based on the use of HCl leaching plus different enzymatic hydrolysis (with and without mercury complexing agents), and the use of focussed ultrasounds (2-mm microtip) is here proposed. Total mercury content in several biological samples was determined by FI–ICP-MS using a carrier solution consisting of 0.1% (v/v) HCl, 0.1% (v/v) 2-mercaptoethanol, to avoid memory effect, and 0.15% (w/v) KCl. For mercury speciation a RP18 chromatographic column coupled to ICP-MS was used. A mobile phase consisting of 0.1% (v/v) formic acid, 0.1% (v/v) HFBA, 2% (v/v) methanol, and 0.02% (w/v) mM l-cysteine at pH 2.1 was used for chromatographic separation of the mercury species in the sample extracts. Extraction procedures were validated by using 50mg of tuna fish tissue CRM-463 (2.85±0.16mgkg−1 for methylmercury). The recoveries obtained were 99±3% and 93±1% after acid leaching (HCl 7M) and enzymatic extraction (15mg protease type XIV in 2.5% (v/v) 2-mercaptoethanol), respectively. The optimal sonication conditions (5min of exposure time and 40% of ultrasound amplitude) were applied to 5mg of CRM-463 (88±5%), 5mg of mussel tissue (81±11%) and to 2mg of zebra fish embryos (90±10%) obtaining good recoveries in all cases. Methylmecury was found to be the most abundant Hg specie in all samples. The developed method is simple and rapid (5min sample treatment); it is suitable for very small samples and does not alter the original form of the mercury species. Thus, it is of special interest in those cases in which validation of the results may often be hampered by lack of sample availability. [Copyright &y& Elsevier]

Abstract: A rapid, low-cost, high sensitive and quantitative method to detect valiolamine in a medium for microbial culture, involving derivatization with a new labeling reagent, 4-methoxybenzenesulfonyl fluoride (MOBS-F), followed by reverse-phase high-performance liquid chromatography with ultraviolet (UV) detection with simple operation procedure. 4-Methoxybenzenesulfonyl chloride (MOBS-Cl) and 2-nitrobenzenesulfonyl chloride (NBS-Cl) were compared with MOBS-F as novel reagents in this paper, and the MOBS-F was chosen as the most suitable derivatization reagent. The column was thermostatic at 35°C, the mobile phase flow-rate was 1.0mL/min and the detection wavelength was 240nm. For a biological sample, the separation of the derivatives was achieved using a gradient mobile system. The elution program is 88% phosphate buffer (50mM; pH=3.0) and 12% methanol for 23min, then 70% of phosphate buffer and 30% methanol for another 15min and finally 88% of phosphate buffer and 12% of methanol for 5min to re-equilibrate the column. The optimized conditions of the derivatization were as follows: derivatization reaction temperature 30°C; derivatization reaction pH value 11.0, reaction time 10min and MOBS-F concentration higher than 1.5mg/mL for standard solutions and higher than 5.0mg/mL for the biological sample. Calibration curves were linear in the range of 0.050–25μg/mL for the standard solutions and 1.0–75μg/mL for the biological sample. The sensitive analytical method is helpful to control the biotechnological process of voglibose production and product quality control. [Copyright &y& Elsevier]

Abstract: In this paper, a solid-phase extraction (SPE) method based on mixed hemimicelles of cetyltrimethyl ammonium bromide (CTAB) on silica-coated magnetic nanoparticles (MNPs) is developed for extraction and preconcentration of compounds from the biological samples. We selected rhein and emodin which are the major active anthraquinones of rhubarb as model analytes. A high performance liquid chromatography–fluorescence detection (HPLC/FLD) method was developed for the determination of rhein and emodin in urine and serum samples. The main factors influencing the extraction efficiency including the amount of surfactant, the concentration of MNPs, the shaking time and the desorption ability of organic solvents were investigated and optimized. No interferences were caused by proteins or endogenous compounds in urine and serum samples. Good linearities (r 2 >0.9995) for all calibration curves were obtained, and the limits of detection (LODs) for rhein and emodin were 0.2 and 0.5ng/mL in urine samples and 7 and 10ng/mL in serum samples, respectively. Satisfactory recoveries (92.76–109.90% and 97.53–107.72% for rhein and emodin) in the biological matrices were achieved. [Copyright &y& Elsevier]

Abstract: Aristolochic acids (AAs) are a mixture of structural-related compounds, in which aristolochic acid I (AA I) and aristolochic acid II (AA II) are reported to be correlated with Aristolochic acid nephropathy (AAN). In this work, a rapid and sensitive ultra-high-pressure liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) method was developed to determine AA I and AA II in herbal products and biological fluids. By using gradient elution with a mobile phase composed of a mixture of 10mM ammonium formate buffer (pH 3.0) and acetonitrile, AAs could be determined within 10min. Under optimum UHPLC–MS/MS conditions, the limit of detections was 0.14 and 0.26ngmL−1 for AA I and AA II, respectively. Run-to-run repeatability and intermediate precision of peak area for AA I and AA II were less than 5.74% relative standard deviation (RSD). Accuracy was tested by spiking 10, 100 and 1000ngmL−1 in rat serum and the recoveries were within 76.5–92.9%. Matrix effects were within 78.8–127.7%. The developed method was successfully applied to determine AA I and AA II in several herbal products and to investigate their pharmacokinetic behavior in female Wister rats. The result shows that the developed UHPLC–MS/MS method is efficient, sensitive, and accurate for the determination of AA I and AA II in herbal products and biological samples. [Copyright &y& Elsevier]

Abstract: The quantitative determination of chemical elements in organic or biological samples is an important analytical problem. Normally the elements to be determined in the organic matrix must be transformed into a simple inorganic form. A digestion method by heating on a block digestor has been developed for the determination of Al, As, Ba, Ca, Cd, Co, Cu, Fe, Mg, Mn, V and Zn in Oyster tissue by ICP OES. A simplex centroid statistical mixture design has been used to study the effects of changing HNO3, HCl and H2O2 reagent proportions on the digestion of these samples. Response surface and principal component analyses show that the species Ca, Cd, Cu, Fe, Mg, Mn and Zn have very similar analytical tendencies under this experiment. By means of mixture modeling maximum recoveries for these ions were predicted using 19%, 18% and 63% of the HCl, HNO3 and H2O2 pseudocomponent mixtures, respectively. This corresponds to 21.4%, 30.8% and 47.8% of the HCl, HNO3 and H2O2 commercial solutions. Furthermore the As, Co and V ions present large recoveries for these mixtures as well. The Al and Ba ion recoveries are seen to be independent of the mixture proportions. The analysis of Oyster tissue reference material (SRM 1566b – NIST) under optimized conditions at the selected wavelengths resulted in ion recoveries between 90% and 100%. [Copyright &y& Elsevier]

Abstract: Microwave-assisted sample preparation using diluted nitric acid solutions is an alternative procedure for digesting organic samples. The efficiency of this procedure depends on the chemical properties of the samples and in this work it was evaluated by the determination of crude protein amount, fat and original carbon. Soybeans grains, bovine blood, bovine muscle and bovine viscera were digested in a cavity-microwave oven using oxidant mixtures in different acid concentrations. The digestion efficiency was evaluated based on the determination of residual carbon content and element recoveries using inductively coupled plasma optical emission spectrometry (ICP OES). In order to determine the main residual organic compounds, the digests were characterized by nuclear magnetic resonance (1H NMR). Subsequently, studies concerning separation of nitrobenzoic acid isomers were performed by ion pair reversed phase liquid chromatography using a C18 stationary phase, water:acetonitrile:methanol (75:20:5, v/v/v)+0.05% (v/v) TFA as mobile phase and ultraviolet detection at 254nm. Sample preparation based on diluted acids proved to be feasible and a recommendable alternative for organic sample digestion, reducing both the reagent volumes and the variability of the residues as a result of the process of decomposition. It was shown that biological matrices containing amino acids, proteins and lipids in their composition produced nitrobenzoic acid isomers and other organic compounds after cleavage of chemical bonds. [Copyright &y& Elsevier]

Abstract: The cloud point extraction (CPE) preconcentration of ultra-trace amount of mercury species prior to reverse-phase high performance liquid chromatography (HPLC) with inductively coupled plasma mass spectrometry (ICP-MS) detection was studied. Mercury species including methyl-, ethyl-, phenyl- and inorganic mercury were transformed into hydrophobic chelates by reaction with sodium diethyldithiocarbamate, and the hydrophobic chelates were extracted into a surfactant-rich phase of Triton X-114 upon heating in a water bath at 40°C. Ethylmercury was found partially decomposed during the CPE process, and was not included in the developed method. Various experimental conditions affecting the CPE preconcentration, HPLC separation, and ICP-MS determination were optimized. Under the optimized conditions, detection limits of 13, 8 and 6ngl−1 (as Hg) were achieved for MeHg+, PhHg+ and Hg2+, respectively. Seven determinations of a standard solution containing the three mercury species each at 0.5ngml−1 level produced relative standard deviations of 5.3, 2.3 and 4.4% for MeHg+, PhHg+ and Hg2+, respectively. The developed method was successfully applied for the determination of the three mercury species in environmental water samples and biological samples of human hair and ocean fish. [Copyright &y& Elsevier]

Abstract: In this study, a new capillary electrophoresis (CE) method is described originally for the sensitive and selective determination of short-chain aliphatic amines in biological samples. These amines were converted into their N-hydroxysuccinimidyl fluorescein-O-acetate (SIFA) derivatives and measured by micellar electrokinetic capillary chromatography with laser-induced fluorescence detection. The derivatization conditions and separation parameters for the aliphatic amines were optimized in detail. The SIFA-labeled amines were fully separated within 8.5min using 25mM pH 9.6 boric acid electrolyte containing 60mM sodium dodecyl sulfate (SDS). The parameters of validation such as linearity of response, precision and detection limits were determined. The detection limits were obtained in the range from 0.02 to 0.1nM, which was the lowest value reported by CE methods. The developed method was successfully employed to monitor aliphatic amines in serum and cells samples. After comparison of other CE methods using different fluorescent probes, the present method represents a powerful tool for the trace determination of aliphatic amines in complex biological samples. [Copyright &y& Elsevier]

Abstract: Non-steroidal anti-inflammatory drugs (NSAIDs) are the group most often used in human health care, since they are available without prescription for treatment of fever and minor pain. The present review submitted the use of various analytical techniques for the determination of oxicams, nimesulide and nabumetone. This review covers the time period from 1990 to 2008 during which over 200 analytical methods including all types of chromatographic, spectrophotometric and voltammetric techniques were reported. Presented application concerns analysis of chosen NSAIDs from pharmaceutical formulations and biological samples. [Copyright &y& Elsevier]

A method combining magnetic solid-phase extraction (MSPE) and ultra-high-pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed for the analysis of aristolochic acids I (AAI) in mouse serum and tissues. The magnetic covalent organic frameworks (MNP@COF)-based MSPE exhibited high adsorption capacity towards AAI (93.1 mg/g) in optimal conditions. After MSPE extraction, AAI was separated with C18 column using gradient elution and quantified (m/z 342.21 → 298.13) by UHPLC-MS/MS with monitor reaction monitoring (MRM) mode. This MSPE-based UHPLC-MS/MS method was validated with respected to lower limit of quantification (LLOQ), linearity, recovery, precision and accuracy of intra- and inter-day, and matrix effect. Good calibration linearities at the range of 1–500 ng/L for AAI in biological matrices (serum, kidney, and liver) with high correlation coefficient (R2) > 0.9970, and high enrichment factors (mean values from 1038 to 1045) were obtained. This method was highly sensitive to determine AAI with LLOQ within the range of 4.62–5.24 ng/L in extracted serum, kidney, and liver samples. Recoveries at 5, 50, 100 and 300 ng/L in biological samples ranged from 93.2 to 104.0%, and intra- and inter day accuracy and precision (defined as bias and coefficient of variation, respectively) were below ± 15%. The method was successfully applied in the analysis of biological samples collected from mice exposed with AAI with concentrations range of 0.007–0.041 μg/L for consecutive four days. The established method might be applied for the investigation of risk assessment and toxicity induced by long-time use of AAI-containing herbs or dietary supplements. [Display omitted] • A magnetic covalent organic framework (MNP@COF) was served as magnetic solid-phase extraction (MSPE) adsorbent. • MSPE adsorbent exhibited high adsorption performance towards aristolochic acids I (AAI). • The MSPE-UHPLC-MS/MS method was applied to detect trace AAI in mice blood and tissues. [ABSTRACT FROM AUTHOR]

Abstract: An on-line inorganic and organomercury species separation, preconcentration and determination system consisting of cold vapor atomic absorption spectrometry (CV-AAS or CV-ETAAS) coupled to a flow injection (FI) method was studied. The inorganic mercury species was retained on a column (i.d., 3mm; length 3cm) packed to a height of 0.7cm with a chelating resin aminopropyl-controlled pore glass (550Å) functionalized with [1,5-bis (2 pyridyl)-3-sulphophenyl methylene thiocarbonohydrazyde] placed in the injection valve of a simple flow manifold. Methylmercury is not directly determined. Previous oxidation of the organomercurial species permitted the determination of total mercury. The separation of mercury species was obtained by the selective retention of inorganic mercury on the chelating resin. The difference between total and inorganic mercury determined the organomercury content in the sample. The inorganic mercury was removed on-line from the microcolumn with 6% (m/v) thiourea. The mercury cold vapor generation was performed on-line with 0.2% (m/v) sodium tethrahydroborate and 0.05% (m/v) sodium hydroxide as reducing solution. The determination was performed using CV-AAS and CV-ETAAS, both approaches have been used and compared for the speciation of mercury in sea food. A detection limit of 10 and 6ngl−1 was achieved for CV-AAS and CV-ETAAS, respectively. The precision for 10 replicate determinations at the 1μgl−1 Hg level was 3.5% relative standard deviation (R.S.D.), calculated from the peak heights obtained. Both approaches were validated with the use of two certified reference materials and by spiking experiments. By analyzing the two biological certified materials, it was evident that the difference between the total mercury and inorganic mercury corresponds to methylmercury. The concentrations obtained by both techniques were in agreement with the certified values or with differences of the certified values for total Hg2+ and CH3Hg+, according to the t-test for a 95% confidence level. It is amazing how this very simple method is able to provide very important information on mercury speciation. [Copyright &y& Elsevier]

Abstract: A novel sol–gel 3-mercaptopropyltrimethoxysilane (MPTS) modified silica coating was developed for capillary microextraction (CME) of trace Cu, Hg and Pb prior to their on line determination by inductively coupled plasma–atomic emission spectrometry (ICP–AES). This organic–inorganic hybrid coating was in situ created on the inner walls of fused silica capillary using a sol solution containing TMOS (tetramethoxysilane) as a precursor, MPTS as a co-precursor, ethanol as the solvent and hydrochloric acid as a catalyst. The structure of the capillary coating was characterized by FT-IR spectroscopy, Raman spectroscopy, SEM and TEM. The factors affecting on the capillary microextraction of analytes such as pH, sample flow rate and volume, elution solution and interfering ions had been investigated, and the optimized experimental parameters were obtained. Under the optimized conditions, the absorption capacity of MPTS-silica coated capillary was found to be 1.17, 1.96 and 1.19μgm−1 for Cu, Hg and Pb, and the limits of detection were as low as 0.17 0.22 and 0.52ngmL−1, respectively. With a sampling frequency of 12h−1, the relative standard deviations (R.S.D.s) were 4.2, 2.6 and 3.8% (C=4ngmL−1, n =7, sample volume=1mL) for Cu, Hg and Pb, respectively. The proposed method had been successfully applied to the determination of Cu, Hg and Pb in human urine, human serum and preserved egg. To validate the proposed method, certified reference materials of BCR151 milk powder, GBW07601 (GSH-1) human hair, GSBZ 50016-90 and GSB 07-1183-2000 water samples were analyzed and the determined values were in a good agreement with the certified values. [Copyright &y& Elsevier]

Abstract: Method development for the pre-concentration of mercury in human hair, dogfish liver and dogfish muscle samples using cloud-point extraction and cold vapor atomic absorption spectrometry is demonstrated. Before the extraction, the samples were submitted to microwave-assisted digestion in a mixture of H2O2 and HNO3. Cloud point extraction was carried out using 0.5% (m/v) ammonium O,O-diethyldithiophosphate (DDTP) as the chelating agent and 0.3% (m/v) Triton X-114 as the non-ionic surfactant. Phase separation was induced after the addition of Na2SO4 to a final concentration of 0.2molL−1. Aliquots of the final extract were transferred to PTFE tubes and NaBH4 and HCl were added. The mercury vapor was driven to a non-heated quartz tube for measuring the absorbance. The results obtained with salt-induced phase separation were in good agreement with the certified values at a 95% confidence level. An enrichment factor of 10 allowed a detection limit of 0.4ngg−1 to be obtained, which demonstrates the high sensitivity of the proposed procedure for the determination of mercury at trace levels. [Copyright &y& Elsevier]

Abstract: Based on gaseous compound introduction as pyrrolidinecarbodithioate chelates of Cr, Co, Mn and Ni by electrothermal vaporization (ETV) in inductively coupled plasma optical emission spectrometry (ICP-OES), a novel method for the determination of trace Cr, Co, Mn and Ni was developed. It was found that in the presence of ammonium pyrrolidinecarbodithioate (APDC) the trace amounts of analytes were vaporized at a low temperature of 1500°C. The main factors affecting the formation and vaporization of analytes chelates were investigated in detail. Thermal gravimetric analysis of Cr–APDC, Co–APDC, Mn–APDC and Ni–APDC chelates and UV–vis analysis of the sample vapor collected in CHCl3 after vaporization of their chelates indicated that the analytes were vaporized and transported into ICP as their chelates. Under the optimized conditions, the limits of detection (LOD) (3σ) and the relative standard deviations (R.S.D.) of Cr, Co, Mn and Ni were 0.36, 0.19, 0.073 and 0.32 ng, and 3.9, 4.9, 3.8 and 3.3% (c =0.5μgml−1, n =7), respectively. By combination with a solvent extraction step, the proposed method had been successfully applied to analysis of Cr, Co, Mn and Ni in the artificial seawater. To evaluate the accuracy of the developed method, two certified reference materials (human hair GBW 09101 and poplar leaves GBW 07604) were also analyzed, and the determined values obtained were in good agreement with the certified values. [Copyright &y& Elsevier]

Abstract: Total mercury in biological samples was determined by flow injection (FI) cold vapour atomic absorption spectrometry (CVAAS) following tissue solubilization with formic acid. A mixture of potassium bromide and potassium bromate was used to decompose organomercury compounds prior to their reduction with sodium borohydride. A gold amalgam system was used to achieve lower detection limits when required. National Research Council Canada certified reference materials dogfish liver (DOLT-3), dogfish flesh (DORM-2) and lobster hepatopancreas (TORT-2), as well as oyster tissue (NIST SRM 1566b) and mussel tissue (NIST SRM 2976) were used to assess the accuracy of the method. The method of standard additions provided the most accurate results. Limit of detection (LOD) for Hg in the solid sample of 0.001 and 0.01μgg−1 were achieved with and without amalgamation, respectively. The precision of measurement for 1.6ngml−1 methylmercury was 2.7% using the amalgam system. [Copyright &y& Elsevier]

Abstract: A new approach for developing a cloud point extraction-electrothermal atomic absorption spectrometry has been described and used for determination of arsenic. The method is based on phase separation phenomenon of non-ionic surfactants in aqueous solutions. After reaction of As(V) with molybdate towards a yellow heteropoly acid complex in sulfuric acid medium and increasing the temperature to 55°C, analytes are quantitatively extracted to the non-ionic surfactant-rich phase (Triton X-114) after centrifugation. To decrease the viscosity of the extract and to allow its pipetting by the autosampler, 100μl methanol was added to the surfactant-rich phase. An amount of 20μl of this solution plus 10μl of 0.1% m/v Pd(NO3)2 were injected into the graphite tube and the analyte determined by electrothermal atomic absorption spectrometry. Total inorganic arsenic(III, V) was extracted similarly after oxidation of As(III) to As(V) with KMnO4. As(III) was calculated by difference. After optimization of the extraction condition and the instrumental parameters, a detection limit (3σB) of 0.01μgl-1 with enrichment factor of 52.5 was achieved for only 10ml of sample. The analytical curve was linear in the concentration range of 0.02–0.35μgl-1. Relative standard deviations were lower than 5%. The method was successfully applied to the determination of As(III) and As(V) in tap water and total arsenic in biological samples (hair and nail). [Copyright &y& Elsevier]

As taurine is a very important compound involved in a large number of metabolic processes, it is naturally present in the mammal tissues and is often deliberately added in some foods as a fortifying component. A detailed knowledge of taurine metabolic roles in biological systems can be obtained only if a sensitive, reliable and rapid analytical method is available. This article describes the successful application of high-performance anion-exchange chromatography coupled with integrated pulsed amperometric detection (HPAEC-IPAD) for taurine determination in egg white and yolk samples, as well extracts of human serum and urine. Applications are shown for determination of taurine in soft drinks and pharmaceutical preparations where the taurine content was evaluated by standard additions. These results were achieved without prior derivatization of taurine. [Copyright &y& Elsevier]

This article reviews some of the recent developments in the extraction and clean-up areas of biological samples dedicated to dioxin and related compound analysis. A brief introduction on the major dioxin contamination events, which have occurred in the food chain, is given to illustrate the need of fast high throughput methods in case of crises. The emphasis of this paper is the method development based upon reliable instrumental extraction techniques for rapid sample processing and automation such as; supercritical fluid extraction (SFE), microwave-assisted extraction (MAE), pressurized liquid extraction (PLE) and, solid-phase extraction (SPE). The PLE and SPE are also discussed in conjunction with the use of a multi-column automated clean-up system that can accommodate up to 5 g of extracted lipids. The fractionation in sub-groups of analytes during the clean-up process allows the isolation of various types of toxicants from a single sample and illustrates the versatility of the system. An integrated extraction and clean-up instrument is finally presented in terms of feasibility and attainable sample turnover for the parallel processing of liquid and solid biological samples. [Copyright &y& Elsevier]

A flow injection (FI) method was developed using hydraulic high-pressure nebulization as a sample introduction system, coupled to inductively coupled plasma time-of-flight mass spectrometer (ICP-TOFMS) for rapid and simultaneous determination of 19 elements. The operating conditions of the system (analyte flow rate, heating and cooling temperatures of the desolvation module, carrier gas flow rate) for the simultaneous determination of 19 analytes were optimised. The optimum parameters of the sample introduction system were found to be 1.4 ml min-1 and 1.35 l min-1 for the analyte solution and nebulizer flow rates, respectively. A compromised condition for heating and cooling stage temperatures of 170 and -5 °C was chosen. The detection limits were compared to those obtained by using ICP-TOFMS with alternative sample introduction techniques e.g. conventional nebulization, flow injection chemical hydride generation (FI-CHG) and the obtained results were comparable or better than those resulting from alternative sample introduction. Applying the optimised conditions the simultaneous determination of Ag, As, Ba, Cd, Co, Cu, Ga, In, Li, Mn, Mo, Pb, Sb, Se, Sn, Sr, Tl, V and Zn was carried out. Absolute detection limits (3σ) in the range of 2–750 pg and precision between 0.5 and 9.6% from five replicate measurements of 10 ng ml-1 multielemental sample solutions were achieved by using a 200 μl sample loop. The developed method was applied for the analysis of certified reference materials of biological origin (TORT-2 “Lobster Hepatopancrease”, BCR-422 “Cod Muscle” and IAEA MA-B-3/TM “Fish Homogenate”), and the results showed good agreement with the certified values. [Copyright &y& Elsevier]

The determination of homocysteine has gained high interest within the biomedical community over recent years as the molecule is an important biomarker for a wide range of diseases. The current report gives a brief overview into the biological significance of homocysteine and a rigorous account of the existing detection protocols for homocysteine in biological fluids, as well as trying to anticipate possible future trends in the development of rapid, low-cost and sensitive assays for its detection. [Copyright &y& Elsevier]