Synthesis and characterization of molecularly imprinted polymers for the selective extraction of oxazepam from complex environmental and biological samples.

Oxazepam, one of the most frequently prescribed anxiolytic drugs, is not completely removed from wastewater with conventional treatment processes. It can thus be found at trace levels in environmental water, with human urine constituting the major source of contamination. This study focused on the development and characterization of molecularly imprinted polymers (MIPs) for the selective solid-phase extraction of oxazepam at trace levels from environmental water and human urine samples. Two MIPs were synthesized, and their selectivity in pure organic and aqueous media were assayed. After optimizing the extraction procedure adapted to a large sample volume to reach a high enrichment factor, the most promising MIP was applied to the selective extraction of oxazepam from environmental water. Extraction recoveries of 83 ± 12, 92 ± 4 and 89 ± 10% were obtained using the MIP for tap, mineral and river water, respectively, while a recovery close to 40% was obtained on the corresponding non-imprinted polymer (NIP). Thanks to the high enrichment factors, a limit of quantification (LOQ) of 4.5 ng L-1 was obtained for river water. A selective extraction procedure was also developed for urine samples and gave rise to extraction recoveries close to 95% for the MIP and only 23% for the NIP. Using the MIP, a LOQ of 357 ng L-1 was obtained for oxazepam in urine. The use of the MIP also helped to limit the matrix effects encountered for the quantification of oxazepam in environmental samples and in human urine samples after extraction on an Oasis HLB sorbent.

Comparison of three electromembrane-based extraction systems for NSAIDs analysis in human urine samples.

A comparative study on the extraction efficiency of five non-steroidal anti-inflammatories was carried out using three different electromembrane extraction (EME) devices with different geometries. The employed setups were (a) a hollow fiber configuration (HF-EME), (b) a microfluidic device that allows working in semi-dynamic mode (µF-EME), and (c) a static miniaturized flat membrane device (FM-EME). Each system was applied to the extraction of salicylic acid (SAC), ketoprofen (KTP), naproxen (NAX), diclofenac (DIC), and ibuprofen (IBU) and subsequent determination by high-performance liquid chromatography with UV and fluorescence detection (HPLC/UV-DAD-FLD). Voltage, pH composition, and extraction time were optimized for all devices. Additionally, volume ratio was investigated for HF-EME and FM-EME and flow rate for the microfluidic device. HF-EME provides the best result in terms of sensitivity with a limit of detection (LOD) between 0.1 and 1.5 ng mL-1 for SAC and KTP, respectively, while LODs for µF-EME were between 100 ng mL-1 and 400 ng mL-1 for SAC and DIC, respectively; however, a lower amount of sample was required. Finally, the obtained results, in terms of enrichment factors and extraction recoveries, were discussed to establish the advantages and disadvantages of each device. The proposed EME methods were successfully applied to the determination of the target analytes in fortified human urine samples. Graphical abstract.

Simple, rapid, and cost-effective microextraction by the packed sorbent method for quantifying of urinary free catecholamines and metanephrines using liquid chromatography-tandem mass spectrometry and its application in clinical analysis.

Pheochromocytoma and paraganglioma (PPGL) are rare neuroendocrine tumors arising from adrenal and extra-adrenal chromaffin cells. They produce excessive amounts of catecholamines and their metabolites. A newly analytical procedure based on the semi-automated microextraction by packed sorbent (MEPS) technique, using a digitally controlled syringe (eVol) combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS), was developed to quantify free urinary catecholamines and metanephrines. The important parameters affecting MEPS performance, namely the type of sorbent material (porous graphitized carbon (PGC), polar enhanced polymer (PEP), cation-exchange (CX) and C18), number of extraction cycles, and elution solvent system, were evaluated. The optimal experimental conditions involved the loading of sample mixture in seven extraction cycles through a C18 sorbent in a MEPS syringe, followed by using elution solutions (water/acetonitrile/formic acid, 95/4.75/0.25). The entire sample preparation took about 4 min. Chromatographic separation was well achieved with an HSS PFP column using the gradient elution. The linearity range of the method was 0.167-33.4 ng/mL for epinephrine, 0.650-130 ng/mL for norepinephrine, 1.53-306 ng/mL for dopamine, 1.34-268 ng/mL for metanephrine, 3.43-686 ng/mL for normetanephrine, and 1.33-265 ng/mL for 3-methoxytyramine. The intra- and interassay precisions were ≤ 12.8%, and the respective accuracies were 88.4-112.0% and 89.0-109.5%. The carryover and sample stability without acidification were also investigated. Validation using clinical urine specimens showed that the proposed method had higher sensitivity compared with other urinary biochemical tests. The developed MEPS-LC-MS/MS method was simple, fast, and cost-effective; it helped to obtain information about multiple metabolites. It is applicable in routine clinical laboratories for the screening of PPGL. Graphical abstract.

Assay of 1-hydroxypyrene via aggregation-induced quenching of the fluorescence of protamine-modified gold nanoclusters and 9-hydroxyphenanthrene-based sensitization.

This work describes a method for the determination of 1-hydroxypyrene (OH-Py) via aggregation-induced quenching of the emission of protamine-coated gold nanoclusters using 9-hydroxyphenanthrene (OH-Phe) as a sensitizer to boost the emission efficiency of nanoprobe. Under optimum conditions, the drop in fluorescence intensity at excitation/emission wavelengths of 300/596 nm is proportional to the concentrations of OH-Py in the range from 1.0 to 65 nM. The relative standard deviations are 4.2, 2.4 and 1.9% (for n = 11) at concentration levels of 8.0, 32 and 48 nM of OH-Py, respectively. The detection limit is 0.3 nM which is much lower than that of some previously reported methods. The recoveries from urine samples spiked with OH-Py ranged between 94.4 and 98.8%. Graphical abstract 1-Hydroxypyrene (OH-Py) can trigger the aggregation of protamine-gold nanoclusters (PRT-AuNCs), resulting in the emission quenching of PRT-AuNCs. 9-Hydroxyphenanthrene (OH-Phe) can boost the emission efficiency of nanoprobe. Thereby, a highly sensitive assay of OH-Py was established.

Protein-templated Fe2O3 microspheres for highly sensitive amperometric detection of dopamine.

The authors describe an amperometric sensor for dopamine (DA) by employing olive-like Fe2O3 microspheres (OFMs) as the electrocatalyst for DA oxidization. The OFMs were prepared by using a protein templated method. The structure and properties of the OFMs were characterized by scanning electron microscopy, X-ray powder diffraction, energy dispersive x-ray spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The OFMs possess excellent catalytic activity towards DA oxidization due to their unique morphology. The sensor responds to DA within less than 5 s. The sensor, best operated at a voltage of +0.2 V (vs. SCE) responds linearly in the 0.2 to 115 µM DA concentration range and has a 30 nM detection limit. The selectivity, reproducibility and long-term stability of the sensor are acceptable. It performs well when applied to spiked human urine samples. Graphical abstract Olive-like Fe2O3 microspheres (OFMs), synthesized using egg white as template, display excellent catalytic activity towards dopamine (DA) oxidization due to their unique morphology. They were applied for DA detection using the amperometric technique. The electrochemical sensor exhibited a high sensitivity and a 30 nM detection limit. DAQ: dopaquinone.

Glycine functionalized multiwall carbon nanotubes as a novel hollow fiber solid-phase microextraction sorbent for pre-concentration of venlafaxine and o-desmethylvenlafaxine in biological and water samples prior to determination by high-performance liquid chromatography.

A hollow fiber solid-phase microextraction method for pre-concentration of venlafaxine and o-desmethylvenlafaxine in biological matrices is described for the first time. The functionalized MWCNTs with an amino acid, glycine, were synthesized and held in the pore of a hollow fiber by sol-gel technique. In order to extract venlafaxine and o-desmethylvenlafaxine from real samples, the hollow fiber was immersed into the sample solution under a magnetic stirring for 20 min. The extracted venlafaxine and o-desmethylvenlafaxine from the fibers were then desorbed with methanol by sonication and analyzed using high-performance liquid chromatography. Important microextraction parameters including pH of donor phase, donor phase volume, stirring rate, extraction time, and desorption conditions such as the type and volume of solvents and desorption time were thoroughly investigated and optimized. The optimized technique provides good repeatability (RSD of the intraday precision 3.7 and 3.4, interday precision of 5.8 and 5.4 %), linearity of (0.1-300 and 0.2-360 ng mL(-1)), low LODs of (0.03 and 0.07 ng mL(-1)), and high enrichment factor of (164 and 176) for venlafaxine and o-desmethylvenlafaxine, respectively. The analytical performance of Gly-MWCNTs as a new SPME sorbent was compared with MWCNTs and carboxylic MWCNTs. The results indicate that Gly-MWCNTs are quite effective for extraction of venlafaxine and o-desmethylvenlafaxine. Feasibility of the method was evaluated by analyzing human urine and real water samples. The results obtained in this work show a promising, simple, selective, and sensitive sample preparation and determination method for biological and water samples.

Fluorescence photobleaching of urine for improved signal to noise ratio of the Raman signal - An exploratory study.

Urine analysis is an important clinical test routinely performed in pathology labs for disease diagnosis and prognosis. In recent years, near-infrared Raman spectroscopy has drawn considerable attention for urine analysis as it can provide rapid, reliable, and reagent-free analysis of urine samples. However, one important practical problem encountered in such Raman measurements is the orders of magnitude stronger spectral background preventing one to utilize the full dynamic range of the detector which is required for the measurement of Raman signal with good signal-to-noise ratio (SNR). We report here the results of an exploratory study carried out on human urine samples to show that the photobleaching, which is a major disadvantage during the fluorescence measurement, could be utilized for suppressing the measured background to improve the SNR of the Raman peaks. It was found that once the photobleaching reached its plateau, there were improvements by ~67% and ~47% in the SNR and the signal to background ratio (SBR), respectively, of the Raman signals as compared to the spectra measured at the start of acquisition. Further, the reduced background also allowed us to utilize the full dynamic range of the detector at increased integration time without saturating the detector indicating the possibility of obtaining an improved detection limit.

Application of Solid Phase Extraction and High-Performance Liquid Chromatography with Fluorescence Detection to Analyze Bisphenol A Bis (2,3-Dihydroxypropyl) Ether (BADGE 2H2O), Bisphenol F (BPF), and Bisphenol E (BPE) in Human Urine Samples.

In this study, we propose a simple, cost-effective, and sensitive high-performance liquid chromatography method with fluorescence detection (HPLC-FLD) for the simultaneous determination of the three bisphenols (BPs): bisphenol A bis (2,3-dihydroxypropyl) ether (BADGE 2H2O), bisphenol F (BPF), and bisphenol E (BPE) in human urine samples. The dispersive solid phase extraction (d-SPE) coupled with solid phase extraction (SPE) procedure performed well for the analytes with recoveries in the range of 74.3-86.5% and relative standard deviations (RSD%) less than 10%. The limits of quantification (LOQs) for all investigated analytes were in the range of 11.42-22.35 ng mL-1. The method was validated at three concentration levels (1 × LOQ, 1.5 × LOQ, and 3 LOQ). During the bisphenols HPLC-FLD analysis, from 6 min a reinforcement (10 or 12) was used, therefore analytes might be identified in the small volume human urine samples. The results demonstrated clearly that the approach developed provides reliable, simple, and rapid quantification and identification of three bisphenols in a urine matrix and could be used for monitoring these analytes.

Rapid, sensitive and simultaneous determination of 16 endocrine-disrupting chemicals (parabens, benzophenones, bisphenols, and triclocarban) in human urine based on microextraction by packed sorbent combined with liquid chromatography tandem mass spectrometry (MEPS-LC-MS/MS).

A high demand exists in human biomonitoring studies for reliable and straightforward methods that generate data faster and simultaneously. Thus, the present study combines microextraction by packed sorbent (MEPS) and liquid chromatography coupled to mass spectrometry (LC-MS/MS) for simultaneous extraction and determination of various classes of endocrine-disrupting chemicals (EDCs), including parabens, benzophenones, bisphenols, and the antimicrobial, triclocarban in human urine samples. Optimized MEPS conditions were: i) MEPS sorbent (C18), ii) pH of sample (3), iii) volume of sample (250 µL), iv) number of draws-eject cycles (5) and (vi) desorption solvent conditions (100 µL of CH3OH:H2O 80:20 v/v). The calibration curves were linear over the selected ranges for all studied compound, with correlation coefficients higher than 0.99. The variation coefficient for precision was lower than 20% at lower concentrations and lower than 15% at the higher concentrations studied. The accuracy ranged from 90% to 118%. The proposed strategy affords several advantages over currently published approaches, including simplicity of operation and reduction of sample and solvent volumes and time for matrix clean-up. Moreover, the analytical performance of each MEPS cartridge remained stable over the analysis of at least 70 samples (RSD < 10%). Thus, the current procedure may be an interesting high-throughput alternative for large routine human biomonitoring studies. Urinary geometric mean concentrations of EDCs obtained in this study were close than those previously reported for Brazilian children.

In Vitro and In Vivo Metabolite Identification Studies for the New Synthetic Opioids Acetylfentanyl, Acrylfentanyl, Furanylfentanyl, and 4-Fluoro-Isobutyrylfentanyl.

New fentanyl analogs have recently emerged as new psychoactive substances and have caused numerous fatalities worldwide. To determine if the new analogs follow the same metabolic pathways elucidated for fentanyl and known fentanyl analogs, we performed in vitro and in vivo metabolite identification studies for acetylfentanyl, acrylfentanyl, 4-fluoro-isobutyrylfentanyl, and furanylfentanyl. All compounds were incubated at 10 µM with pooled human hepatocytes for up to 5 h. For each compound, four or five authentic human urine samples from autopsy cases with and without enzymatic hydrolysis were analyzed. Data acquisition was performed in data-dependent acquisition mode during liquid chromatography high-resolution mass spectrometry analyses. Data was analyzed (1) manually based on predicted biotransformations and (2) with MetaSense software using data-driven search algorithms. Acetylfentanyl, acrylfentanyl, and 4-fluoro-isobutyrylfentanyl were predominantly metabolized by N-dealkylation, cleaving off the phenethyl moiety, monohydroxylation at the ethyl linker and piperidine ring, as well as hydroxylation/methoxylation at the phenyl ring. In contrast, furanylfentanyl's major metabolites were generated by amide hydrolysis and dihydrodiol formation, while the nor-metabolite was minor or not detected in case samples at all. In general, in vitro results matched the in vivo findings well, showing identical biotransformations in each system. Phase II conjugation was observed, particularly for acetylfentanyl. Based on our results, we suggest the following specific and abundant metabolites as analytical targets in urine: a hydroxymethoxy and monohydroxylated metabolite for acetylfentanyl, a monohydroxy and dihydroxy metabolite for acrylfentanyl, two monohydroxy metabolites and a hydroxymethoxy metabolite for 4-fluoro-isobutyrylfentanyl, and a dihydrodiol metabolite and the amide hydrolysis metabolite for furanylfentanyl.

Investigation of diethylstilbestrol residue level in human urine samples by a specific monoclonal antibody.

Diethylstilbestrol (DES) is used as a kind of animal feed additive and affects people's health through the food chain. The purpose of this study is to detect the residue level of DES in 576 human urine samples directly. DES-BSA was used to immunize Balb/c mice. The monoclonal antibody was produced by hybridoma that was screened through cell fusion techniques. Finally, we developed the indirect competitive ELISA method to analyze 576 human urine samples from Zhejiang Province, China. The IC50 of this method was 3.33 ng/mL. The LOD and LOQ were 0.16 and 0.54 ng/mL. Linear range of the standard curve was from LOD to 12.50 ng/mL. There was no cross-reactivity with two kinds of estrogens and two structural analogs with DES. Five hundred seventy-six urine samples were analyzed by the indirect competitive ELISA method, and the detection rate was 98.78%. The mean concentration and geometric mean were 4.70 and 3.50 ng/mL. The indirect competitive ELISA method based on monoclonal antibody was sensitive and reliable for the detection of DES in human urine samples. The results warned us to pay more attention to human health and food safety.

Exposure to benzophenones, parabens and triclosan among pregnant women in different trimesters.

Humans are potentially exposed to many environmental pollutants, many of which may cause adverse health effects, especially to pregnant women and their fetuses. In this study, 11 environmental pollutants from three different chemical classes, including benzophenones, parabens and triclosan were measured in 627 urine samples collected from 209 pregnant women to evaluate exposure and trends as a function of pregnancy stage. Methylparaben (MeP), ethylparaben, propylparaben (PrP), butylparaben, 2,4-dihydroxybenzophenone (BP-1), 2-hydroxy-4-methoxybenzophenone (BP-3) and 4-hydroxybenzophenone were detected in >50% samples. The concentrations of BP-1 and BP-3 (Spearman's r=0.57, p<0.01) and those of MeP and PrP (Spearman's r=0.68, p<0.01) were found to be correlated. The urinary concentrations of BP-1 and BP-3 in the first trimester were significantly higher than those in the second or third trimester (Mann-Whitney U test, p<0.05). These findings provide valuable information for improving the prediction of maternal exposure to these emerging pollutants and for assessing their potential health risks to the mother as well as the offspring.

Analytical approach to determining human biogenic amines and their metabolites using eVol microextraction in packed syringe coupled to liquid chromatography mass spectrometry method with hydrophilic interaction chromatography column.

Analysis of biogenic amines (BAs) in different human samples provides insight into the mechanisms of various biological processes, including pathological conditions, and thus may be very important in diagnosing and monitoring several neurological disorders and cancerous tumors. In this work, we developed a simple and fast procedure using a digitally controlled microextraction in packed syringe (MEPS) coupled to liquid chromatography mass spectrometry (LC-MS) method for simultaneous determination of biogenic amines, their precursors and metabolites in human plasma and urine samples. The separation of 12 low molecular weight and hydrophilic molecules with a wide range of polarities was achieved with hydrophilic interaction chromatography (HILIC) column without derivatization step in 12 min. MEPS was implemented using the APS sorbent in semi-automated analytical syringe (eVol(®)) and small volume of urine and plasma samples, 5 0µL and 100 µL, respectively. We evaluated important parameters influencing MEPS efficiency, including stationary phase selection, sample pH and volume, number of extraction cycles, and washing and elution volumes. In optimized MEPS conditions, the analytes were eluted by 3 × 50 µL of methanol with 0.1% formic acid. The chromatographic separation of analytes was performed on XBridge Amide™ BEH analytical column (3.0mm × 100 mm, 3.5 µm) using gradient elution with mobile phase consisting of phase A: 10mM ammonium formate buffer in water pH 3.0 and phase B: 10mM ammonium formate buffer in acetonitrile pH 3.0. The LC-HILIC-MS method was validated and, in optimum conditions, presented good linearity in concentration range within 10-2000 ng/mL for all the analytes with a determination coefficient (r(2)) higher than 0.999 for plasma and urine samples. Method recovery ranged within 87.6-104.3% for plasma samples and 84.2-98.6% for urine samples. The developed method utilizing polar APS sorbent along with polar HILIC column was applied for simultaneous bioanalysis of trace amounts of polar endogenous biogenic amines in real human urine and plasma samples.

An improved analytical strategy combining microextraction by packed sorbent combined with ultra high pressure liquid chromatography for the determination of fluoxetine, clomipramine and their active metabolites in human urine.

A powerful and sensitive method, by microextraction packed sorbent (MEPS), and ultra-high performance liquid chromatography (UHPLC) with a photodiode array (PDA) detection, is described for the determination of fluoxetine, clomipramine and their active metabolites in human urine samples. The MEPS variables, such as sample volume, pH, number of extraction cycles (draw-eject), and desorption conditions (solvent and solvent volume of elution) were optimized. The analysis were carried out using small sample volumes (500µL) and in a short time period (5min for the entire sample preparation step). Good linearity was obtained for all antidepressants with the correlation coefficients (R(2)) above 0.9965. The limits of detection (LOD) ranged from 0.068 to 0.087µgmL(-1). The recoveries were from 93% to 98%, with relative standard deviations less than 6%. The inter-day precision, expressed as the relative standard deviation, varied between 3.8% and 8.5% while the intra-day precision between 3.0% and 7.1%. In order to evaluate the proposed method for clinical use, the MEPS/UHPLC-PDA method was applied to analysis of urine samples from depressed patients.

Validation of a UHPLC-MS/MS method for quantification of zearalenone, α-zearalenol, ß-zearalenol, α-zearalanol, ß-zearalanol and zearalanone in human urine.

Humans can be exposed to mycotoxins through the diet. Evaluation of exposure levels to mycotoxins can be performed by direct determination in urine. The present work proposes a sensitive ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for the determination of zearalenone (ZON) and its five metabolites (α-zearalenol [α-ZOL], ß-zearalenol [ß-ZOL], α-zearalanol [zeranol, α-ZAL], ß-zearalanol [teranol, ß-ZAL] and zearalanone [ZAN]) in human urine samples. The method involves the enzymatic hydrolysis of the samples, extraction of the analytes using liquid-liquid extraction (LLE) with ethyl acetate/formic acid (99:1 v/v) and a cleanup step using hexane, prior to their quantification by UHPLC-MS/MS, using an electrospray ionization (ESI) interface in the negative mode. Zearalenone-d6 (ZON-d6) was used as surrogate. The limits of detection and the limits of quantification ranged from 0.03 to 0.3ngmL(-1) and from 0.1 to 1.0ngmL(-1), respectively. The method was validated using matrix-matched calibration and a spike recovery assay. Recovery rates for spiked samples ranged from 96% to 104%, with relative standard deviations lower than 8.5%. This method was satisfactorily applied to 42 urine samples from Tunisian women for the determination of zearalenone and its five metabolites.

Rapid microwave assisted synthesis of graphene nanosheets/polyethyleneimine/gold nanoparticle composite and its application to the selective electrochemical determination of dopamine.

In this study, a simple and fast microwave assisted chemical reduction method for the preparation of graphene nanosheet/polyethyleneimine/gold nanoparticle (GNS/PEI/AuNP) composite was developed. PEI, a cationic polymer, was used both as a non-covalent functionalizing agent for the graphene oxide nanosheets (GONSs) through electrostatic interactions in the aqueous medium and also as a stabilizing agent for the formation of AuNPs on PEI wrapped GNSs. This preparation method involves a simple mixing step followed by a simultaneous microwave assisted chemical reduction of the GONSs and gold ions. The prepared composite exhibits the dispersion of high density AuNPs which were densely decorated on the large surface area of the PEI wrapped GNS. X-ray photoelectron spectroscopy, powder X-ray diffraction, high-resolution transmission electron microscopy, field-emission scanning electron microscopy with energy dispersive X-ray spectroscopy, and thermo-gravimetric analysis, were used to characterize the properties of the resultant composite. The prepared GNS/PEI/AuNP composite film exhibited excellent electrocatalytical activity towards the selective determination of dopamine in the presence of ascorbic acid, which showed potential application in electrochemical sensors. The applicability of the presented sensor was also demonstrated for the determination of dopamine in human urine samples.

Field-amplified sample injection coupled with pseudo-isotachophoresis technique for sensitive determination of selected psychiatric drugs in human urine samples after dispersive liquid-liquid microextraction.

A field-amplified sample injection (FASI) technique was elaborated for fast and sensitive determination of selected central nervous system drugs in human urine samples. Factors affecting the sensitivity enhancement, such as background electrolyte (BGE) and the analytical matrix composition were optimized and discussed. Pseudo-isotachophoresis (p-ITP) mechanism contribution in preconcentration mechanism was discussed. All separations were performed in uncoated fused silica capillaries 50 µm × 57 cm at 22 kV. The optimized analytical matrix was composed of 0.25 mM HCOOH in 90% (v/v) methanol, while BGE contained 45 mM TRIS/HCl (pH 2.20). The head-column injection was performed in 0.25 mM HCOOH water solution (3s, 3.45 kPa). Sample was introduced into the capillary by electrokinetic injection (70 s, 5 kV) followed by short BGE plug (3s, 3.45 kPa). Seven psychiatric drugs (olanzapine, prochlorperazine dimaleate, trifluoperazine dihydrochloride, perphenazine, promazine hydrochloride, clomipramine hydrochloride, and chlorprothixene hydrochloride) were separated in about 6 min. The elaborated method was additionally supported with dispersive liquid-liquid microextraction (DLLME) technique which in summary with FASI provided about 8000-13,000-fold sensitivity enhancement in comparison to the capillary zone electrophoresis (CZE) method with standard hydrodynamic injection (5s, 3.45 kPa).

Smartphone-based analysis of biochemical tests for health monitoring support at home.

In the context of home-based healthcare monitoring systems, it is desirable that the results obtained from biochemical tests - tests of various body fluids such as blood and urine - are objective and automatically generated to reduce the number of man-made errors. The authors present the StripTest reader - an innovative smartphone-based interpreter of biochemical tests based on paper-based strip colour using image processing techniques. The working principles of the reader include image acquisition of the colour strip pads using the camera phone, analysing the images within the phone and comparing them with reference colours provided by the manufacturer to obtain the test result. The detection of kidney damage was used as a scenario to illustrate the application of, and test, the StripTest reader. An extensive evaluation using laboratory and human urine samples demonstrates the reader's accuracy and precision of detection, indicating the successful development of a cheap, mobile and smart reader for home-monitoring of kidney functioning, which can facilitate the early detection of health problems and a timely treatment intervention.

Simultaneous Determination of Potassium Clavulanate and Amoxicillin Trihydrate in Bulk, Pharmaceutical Formulations and in Human Urine Samples by UV Spectrophotometry.

A simple and sensitive UV spectrophotometric method was developed and validated for the simultaneous determination of Potassium Clavulanate (PC) and Amoxicillin Trihydrate (AT) in bulk, pharmaceutical formulations and in human urine samples. The method was linear in the range of 0.2-8.5 µg/ml for PC and 6.4-33.6 µg/ml for AT. The absorbance was measured at 205 and 271 nm for PC and AT respectively. The method was validated with respect to accuracy, precision, specificity, ruggedness, robustness, limit of detection and limit of quantitation. This method was used successfully for the quality assessment of four PC and AT drug products and in human urine samples with good precision and accuracy. This is found to be simple, specific, precise, accurate, reproducible and low cost UV Spectrophotometric method.

Development and Validation of Pregabalin in Bulk, Pharmaceutical Formulations and in Human Urine Samples by UV Spectrophotometry.

A simple and sensitive UV spectrophotometric method was developed and validated for the determination of pregabalin in bulk, pharmaceutical formulations and in human urine samples. The method was linear in the range of 0.5-5.0 µg/ml. There is no generally accepted method for the determination of pregabalin. The absorbance was measured at 210 nm. The method was validated with respect to accuracy, precision, specificity, ruggedness, and robustness, limit of detection and limit of quantitation. This method was used successfully for the quality assessment of five pregabalin drug products and in human urine samples with good precision and accuracy. This is found to be simple, specific, precise, accurate, reproducible and low cost UV Spectrophotometric method.