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The ability to quantify levels of target analytes in biological samples accurately and precisely in biomonitoring involves the use of highly sensitive and selective instrumentation such as tandem mass spectrometers and a thorough understanding of highly variable matrix effects. Typically, matrix effects are caused by co-eluting matrix components that alter the ionization of target analytes as well as the chromatographic response of target analytes, leading to reduced or increased sensitivity of the analysis. Thus, before the desired accuracy and precision standards of laboratory data are achieved, these effects must be characterized and controlled. Here we present our review and observations of matrix effects encountered during the validation and implementation of tandem mass spectrometry–based analytical methods. We also provide systematic, comprehensive laboratory strategies needed to control challenges posed by matrix effects in order to ensure delivery of the most accurate data for biomonitoring studies assessing exposure to environmental toxicants. [ABSTRACT FROM PUBLISHER]

Phthalates are endocrine disruptors of the reproductive system and suspected to influence many other organ and hormone systems. They are also semi-volatile organic compounds present in the gas phase in the environment. Their mode of action has been investigated in numerous in vitro studies. Multi-well culture plates are typically used to study phthalates in cell cultures. In a pilot study, we observed evidence of phthalate migration in 24-well culture plates. As this has not previously been described, we investigated the phenomenon in more detail. Primary human thyroid epithelial cell cultures (n = 8 cultures) were exposed to either di-ethyl phthalate (DEP), di-n-butyl phthalate (DnBP), mono-n-butyl phthalate (MnBP) or di-(2-ethylhexyl) phthalate (DEHP). Measurement of phthalate metabolites by mass spectrometry demonstrated that the short-branched DEP was able to migrate to adjacent wells when added to cell culture plates. DnBP also seemed to be able to migrate, unlike the long-branched DEHP or the monoester MnBP which did not seem to have this ability. High background levels of phthalate metabolites were also observed, which might compromise results from low dose phthalate studies. In conclusion, the migration of phthalates which is probably caused by their volatile properties might lead to false interpretation of study results. [ABSTRACT FROM AUTHOR]

The cell wall integrity (CWI) checkpoint in the budding yeast Saccharomyces cerevisiae coordinates cell wall construction and cell cycle progression. In this study, we showed that the regulation of Hcm1, a late-S-phase transcription factor, arrests the cell cycle via the cell wall integrity checkpoint. Although the HCM1 mRNA level remained unaffected when the cell wall integrity checkpoint was induced, the protein level decreased. The overproduction of Hcm1 resulted in the failure of the cell wall integrity checkpoint. We identified 39 Hcm1 phosphorylation sites, including 26 novel sites, by tandem mass spectrometry analysis. A mutational analysis revealed that phosphorylation of Hcm1 at S61, S65, and S66 is required for the proper onset of the cell wall integrity checkpoint by regulating the timely decrease in its protein level. Hyperactivation of the CWI mitogen-activated protein kinase (MAPK) signaling pathway significantly reduced the Hcm1 protein level, and the deletion of CWI MAPK Slt2 resulted in a failure to decrease Hcm1 protein levels in response to stress, suggesting that phosphorylation is regulated by CWI MAPK. In conclusion, we suggest that Hcm1 is regulated negatively by the cell wall integrity checkpoint through timely phosphorylation and degradation under stress to properly control budding yeast proliferation. [ABSTRACT FROM AUTHOR]

Objective: To verify whether small-for-gestational-age (SGA) preterm newborns represent a special risk group for carnitine deficiency. Secondary outcome includes assessment of longitudinal differences of total carnitine (TC), free carnitine (FC) and acylcarnitines between SGA and appropriate-for-gestational-age (AGA).Methods: A retrospective study to evaluate carnitine and acylcarnitines profile on 144 very-low-birth weight newborns (VLBW), classified as AGA (n = 73) and SGA (n = 71), was performed by tandem mass spectrometry, during their first 5 weeks of life. Carnitine deficiency was defined as FC <40 µmol/L and FC/TC <0.7.Results: Carnitine deficiency was observed in the two study groups throughout the monitoring period (maximum FC: 36.05 µmol/L in AGA and 32.24 µmol/L in SGA). FC/TC remains under 0.7 in both with progressive improvement. Unlike expected, a comparatively higher value of TC, FC and total acylcarnitines (tAC) was found in SGA during the first 2 weeks, with significant relevance on day 3-5, especially for tAC (p < 0.001). The only acylcarnitine with persistently lower value in SGA is C5 (p < 0.05 in first 2 weeks).Conclusions: A carnitine deficiency was demonstrated in all VLBW. Although birth weight restriction has been suggested as a risk factor for impaired carnitine status, in our study, SGA was not related with higher carnitine deficiency. [ABSTRACT FROM AUTHOR]

A multi-class, multi-residue analytical method based on LC-MS/MS detection was developed for the screening and confirmation of 28 veterinary drug and metabolite residues in flatfish, shrimp and eel. The chosen veterinary drugs are prohibited or unauthorised compounds in Korea, which were categorised into various chemical classes including nitroimidazoles, benzimidazoles, sulfones, quinolones, macrolides, phenothiazines, pyrethroids and others. To achieve fast and simultaneous extraction of various analytes, a simple and generic liquid extraction procedure using EDTA-ammonium acetate buffer and acetonitrile, without further clean-up steps, was applied to sample preparation. The final extracts were analysed by ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS). The method was validated for each compound in each matrix at three different concentrations (5, 10 and 20 ng g–1) in accordance with Codex guidelines (CAC/GL 71-2009). For most compounds, the recoveries were in the range of 60–110%, and precision, expressed as the relative standard deviation (RSD), was in the range of 5–15%. The detection capabilities (CCβs) were below or equal to 5 ng g–1, which indicates that the developed method is sufficient to detect illegal fishery products containing the target compounds above the residue limit (10 ng g–1) of the new regulatory system (Positive List System – PLS). [ABSTRACT FROM AUTHOR]

Tomato and lettuce are main components of the Mediterranean Diet and it is important to know their content in phenolic compounds, considering they have beneficial effects on human health. In this work, more than 25 phenolic compounds were simultaneously analyzed by ultra-high performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry, including phenolic acids, flavonols, and flavones. Several varieties of lettuce and tomato were evaluated and total phenolic content ranged from 68 to 212 mg/kg dry weight for lettuce, and from 341 to 1296 mg/kg dry weight for tomato, being the chlorogenic acid the compound detected at the highest concentration in both types of vegetables (lettuce from 9 to 126 mg/kg dry weight, tomato from 96 to 538 mg/kg dry weight), although in tomato the content of quercetin-3-O-rutinoside (from 29 to 460 mg/kg dry weight) was also important. On the other hand, the minor compounds detected were quercetin-3-O-derivate (up to 1 mg/kg dry weight) in tomato, and apigeninOderivate, luteolinCglucoside, and isorhamnetin 3-O-glucoside in lettuce. It was observed that the total phenolic content in the plum cherry tomato was significantly higher than in the other varieties, whereas in lettuce, the differences were not statistically different. [ABSTRACT FROM AUTHOR]

Sulfo-functionalized iron oxide magnetic nanobeads were employed as an adsorbent for magnetic solid-phase extraction of benzodiazepines in beef. The analytes were determined by high performance liquid chromatography–mass spectrometry. The sulfo-functionalized iron oxide magnetic nanobeads were characterized by transmission electron microscopy and infrared spectroscopy. The optimal pH, ionic strength, volume of sulfo-functionalized iron oxide magnetic nanobeads, and elution solvent were investigated for the isolation procedure. Under the optimized conditions, the limits of detection for diazepam, oxzepam, triazolam, and chlordiazepoxide were 0.79, 0.22, 0.13, and 0.23 ng/kg, respectively. The method was employed for the determination of the analytes in beef. Compared with established methods, magnetic solid phase extraction and high-performance liquid chromatography–tandem mass spectrometry method exhibited high sensitivity, rapid separation, and low cost. [ABSTRACT FROM PUBLISHER]

Isomaltooligosaccharides are widely used in food with health benefits. A sensitive and selective method for the determination of three isomaltooligosaccharides is reported using ultra-high performance liquid chromatography–tandem mass spectrometry. The method was validated by characterization of the linearity, accuracy, precision, and the limits of detection and quantification. Under the optimized conditions, the calibration relationships were linear for the analytes with correlation coefficients exceeding 0.998. The recoveries were from 91.5% to 107.6% with coefficients of variation below 9.0%. The limits of detection and quantification were 1.20 µg mL−1and 3.60 µg mL−1for isomaltose, 0.15 µg mL−1and 0.50 µg mL−1for panose, and 0.55 µg mL−1and 1.80 µg mL−1for isomaltotriose. The validated method was employed for the determination of isomaltooligosaccharides in milk powder. [ABSTRACT FROM PUBLISHER]

Isocyanate thermal degradation characterization by liquid chromatography coupled with electrospray tandem mass spectrometry has been performed to elucidate the methylene diphenyl diisocyanate (MDI) thermal degradation structure emitted in a generation chamber using a temperature between 50°C and 180°C to produce MDI vapors. [M+H]+ ions containing an isocyanate functional group were studied by tandem mass spectrometry. The [M+H]+ ion analyses based on the combination of full scans and precursor ion scans were useful for identifying all structures. The compounds emitted were identified and validated as a mixture of compounds containing amine and isocyanate functions. Residual MDI, methylene diphenyl amino-isocyanate, and methylene diphenyl diamine were identified. Polymerized forms of these structures were also observed because amine and isocyanate chemical functions react rapidly to polymerize. These results must be used with special care by scientists establishing sensitization diagnostics and developing sampling devices using generation chambers as they must be related to MDI behavior in workplaces. Even if pure MDI is introduced in the generation chamber, several different compounds are generated when the MDI is heated at a high temperature. This can result in some misleading interpretations for non-specific isocyanate sampling device development and sensitization diagnostics as MDI is present in the chamber with other compounds with known adverse effects. [ABSTRACT FROM AUTHOR]

A method for the determination of seven trichothecenes, neosolaniol (NEO), diacetoxyscirpenol (DAS), deoxynivalenol (DON), nivalenol (NIV), fusarenon-X (FUS-X), 3-acetyldeoxynivalenol (3-ADON) and 15-acetyldeoxynivalenol (15-ADON), in laboratory rat feed by GC-MS/MS was developed. Sample extraction and purification was performed by an acidified mixture of acetonitrile/water (80–20% v/v). Limits of quantitation (LOQs) were between 1 and 10 μg kg–1for all studied trichothecenes. Eight concentration levels between the LOQ and 100 × LOQ were used for the calibration curves. Matrix-matched calibration was used for quantitation purposes to compensate the detector signal enhancement obtained for all the analytes. The method accuracy was evaluated by recovery assays at three concentration levels, 25, 50 and 100 μg kg–1(n = 9). Recoveries ranged from 62% to 97% and precision, expressed as intra- and inter-day relative standard deviations, was evaluated for all compounds. The validated method was successfully applied to the analysis of 35 laboratory rat feed samples showing mycotoxin contamination in 66% of the samples. DON was the most prevalent trichothecene followed by 15-ADON, NIV and 3-ADON. The maximum DON concentration reached in real samples was 2156 ± 4.3 μg kg–1, while NEO, DAS and FUS-X were not detected in any sample. Multi-contamination by at least two mycotoxins was observed in 17% of the analysed feed samples. [ABSTRACT FROM PUBLISHER]

This paper investigated the possibility of leaving out the traditional clean-up step in the QuEChERS procedure and analysing non-cleaned extracts from fruit, vegetables and cereals with a combination of gas chromatography-tandem mass spectrometry (GC-MS/MS), back-flush technology and large-volume injection. By using calibration standards in cucumber matrix, recovery and precision were calculated in lettuce, orange and wheat for 109 pesticides at 0.01 and 0.1 mg kg−1in two sets of samples: one with and one without clean-up. For both spiking levels, 80–82% of the pesticides in the non-cleaned extracts and 80–84% of the pesticides in the cleaned extracts were within the acceptable recovery range of 70–120%. Precision data for both levels showed that 95% of the pesticides in the non-cleaned extracts and 93–95% of the pesticides in the cleaned extracts had RSDs below 20%. Recovery and precision data were determined using a two tailedt-test (p = 0.05). By using calibration standards in the respective matrix, we studied if the non-cleaned calibration standards gave an extra matrix effect compared with the cleaned standards by using the slope from calibration graphs and plotting the calculated extra matrix effect minus 100 for each compound. The results showed that for 79% of the pesticides, the extra matrix effect minus 100 was within the acceptable range of −20% to 20%. Five European Union proficiency tests on rye, mandarin, rice, pear and barley, respectively, from 2010 to 2012 were reanalysed omitting the clean-up step and showed satisfactory results. At least 70 injections of non-cleaned extracts were made without detecting any increased need for maintenance during the experimental period. Analysing non-cleaned QuEChERS extracts of lettuce, orange and wheat are possible under the conditions described in this paper because recovery, precision and specificity showed satisfactory results compared with samples subjected to traditional dispersive clean-up. [ABSTRACT FROM AUTHOR]

The aim of this study was to monitor for the first time the oligosaccharide pattern in the northwestern Adriatic Sea. Oligosaccharides are components of the low-molecular-weight fraction of dissolved organic matter (DOM). They perform an important ecological function in the microbial loop prompting substrates for bacterial degradation. In particular, our investigation focused on maltooligosaccharides (glucose α 1–4 linked). The analyses were carried out using a dialysis-charcoal column sorption pre-concentration method, followed by liquid chromatography-tandem mass spectrometry analyses with a triple quadrupole mass spectrometer operating in multiple reaction monitoring mode. During the study period, the concentration of maltooligosaccharides with a low degree of polymerisation (ranging from maltose to maltotetraose) was higher than other maltooligosaccharides (maltopentaose and maltoeptaose) and all together they reached their highest concentration in June. This concentration was temporally shifted from a long period of diatom bloom (from January to April). Furthermore, the annual maltooligosaccharide trend was monitored together with several chemical, physical and biological parameters to investigate their potential role on the maltooligosaccharide accumulation. Our results suggested that the maltooligosaccharide accumulation could be related to the water column stratification. [ABSTRACT FROM AUTHOR]

Norepinephrine reuptake inhibitors (NRIs) are a class of antidepressant drugs that act as reuptake inhibitors for the neurotransmitters norepinephrine and epinephrine. The present review provides an account of analytical methods published in recent years for the determination of NRI drugs. NRIs are atomoxetine, reboxetine, viloxazine and maprotiline. NRIs with less activity at other sites are mazindol, bupropion, tapentadol, and teniloxazine. This review focuses on the analytical methods including chromatographic, spectrophotometric, electroanalytical, and electrophoresis techniques for NRI analysis from pharmaceutical formulations and biological samples. Among all of the published methods, liquid chromatography with UV-vis or MS-MS detection is the most popular technique. The most the common sample preparation techniques in the analytical methods for NRIs include liquid-liquid extraction and solid-phase extraction. Besides the analytical methods for single components, some of the simultaneous determinations are also included in this review. [ABSTRACT FROM AUTHOR]

A series of mono-, di- and tri-substituted arylpentazoles were obtained via different synthetic routes. The effects of the number and position of the substituents on the arylpentazoles stability have been investigated at different temperatures. Investigators used electrospray ionization tandem mass spectrometry to infer the decomposition pathway of arylpentazoles. The article examines the relationship between the arylpentazole stability and the relative intensity of the generated pentazolate anion. [ABSTRACT FROM PUBLISHER]

Tea is the second widely consumed beverage next to water. Tea drinking is one of the important pathways for human exposure of organonphosphorus pesticide. Consequently, incidence of organonphosphorus pesticide residues and risk assessment should be clear. In this study, the level of organonphosphorus pesticide residues in 810 Chinese teas manufactured between 2010–2013 was investigated using gas chromatography coupled with tandem mass spectrometry and a flame photometric detector. Incidence of organonphosphorus pesticide residues occurred with a frequency of 29% and the average concentration of 93 μg kg−1. The residue levels varied from tea types, sale spots, and production area. Chlorpyrifos, isocarbophos, and triazophos were the only three organonphosphorus pesticides with detectable residues, and the detectable rates were 13.0%, 13.6%, and 17.4%, respectively. The corresponding average daily intake of chlorpyrifos, isocarbophos, and triazophos by tea drinking was 0.000083 μg kg−1bw day−1, 0.0036 μg kg−1bw day−1, and 0.0022 μg kg−1bw day−1. These results showed that the total hazard quotient of organonphosphorus pesticide pesticides from tea drinking was less than 0.02 and that the tea-drinking originated organonphosphorus pesticide exposure had a little adverse health effect for human being. [ABSTRACT FROM PUBLISHER]

Objectives: Methiopropamine (MPA; 1-(thiophen-2-yl)-2-methylaminopropane) belongs to the new psychoactive substances (NPS) that have emerged on the drug market in recent years. MPA appeared in 2011 and is an analogue of methamphetamine, sold as, for example, "Slush Eric" and "Blow." It is reported to have effects similar to those of methamphetamine, but the toxicity in humans is not known. Three fatal cases involving MPA have been reported. One analytical confirmed intoxication case has been published, and this supports the symptoms described by the users. The prevalence of recreational use of MPA is unknown, and no studies have reported the prevalence in driving under the influence of drug (DUID) cases.Methods: We investigated the frequency of MPA in DUID cases received at our institute during a 12-week period and report the analytical method using an ultraperformance liquid chromatography.tandem mass spectrometry for quantification of MPA in whole blood. The analytical findings were compared to the results from a clinical test of impairment performed by a physician shortly after the driving episode. The samples were analyzed for 42 different psychoactive substances.Results: MPA was detected in 10 DUID cases (0.8% of the cases), only from male drivers. Other drugs were detected concomitantly in all the cases. Two of the cases were traffic accidents.Conclusions: Our study shows that MPA is found in DUID cases and reveals that NPS are used among drivers and also proven in blood from drivers involved in traffic accidents. More studies are requested regarding the pharmacological and toxicological effects of MPA and other NPS. This is the first article that describes a method for analyzing and quantifying MPA in whole blood samples. [ABSTRACT FROM AUTHOR]

A modified quick, easy, cheap, effective, rugged and safe (QuEChERS) method for the analysis of triallate residue in wheat and soil was developed and validated. Multi-walled carbon nanotubes were used as clean-up sorbent. The residual levels and dissipation rates of triallate in wheat and soil were determined by liquid chromatography–tandem mass spectrometry. The limit of quantification was established as 0.01, 0.02 and 0.05 mg kg−1for soil, wheat and wheat plant samples, respectively. The average recoveries of triallate ranged from 77% to 108% at fortified levels of 0.01–0.5 mg kg−1with relative standard deviations of 3.0–8.4% (n = 5). From residue trials at three geographical experimental plots in China, the results showed that the half-lives of triallate in soils were 1.13–1.63 days. For trials applied according to the label recommendation, the final residues of triallate in wheat at harvest time were all below 0.05 mg kg−1(the maximum residue levels of China, Japan, Korea and the US). [ABSTRACT FROM PUBLISHER]

Seven strobilurin fungicides were pre-concentrated from soya-based drinks using dispersive liquid–liquid micro-extraction (DLLME) with a prior protein precipitation step in acid medium. The enriched phase was analysed by liquid chromatography (LC) with dual detection, using diode array detection (DAD) and electrospray-ion trap tandem mass spectrometry (ESI-IT-MS/MS). After selecting 1-undecanol and methanol as the extractant and disperser solvents, respectively, for DLLME, the Taguchi experimental method, an orthogonal array design, was applied to select the optimal solvent volumes and salt concentration in the aqueous phase. The matrix effect was evaluated and quantification was carried out using external aqueous calibration for DAD and matrix-matched calibration method for MS/MS. Detection limits in the 4–130 and 0.8–4.5 ng g−1ranges were obtained for DAD and MS/MS, respectively. The DLLME-LC-DAD-MS method was applied to the analysis of 10 different samples, none of which was found to contain residues of the studied fungicides. [ABSTRACT FROM PUBLISHER]

An ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) multi-mycotoxin analytical method was developed to simultaneously identify and quantify 20 mycotoxins in grass silages, inclusive of mycotoxins that are currently regulated in European Union feeds. Extraction of mycotoxins from dried grass silages was performed using of a modified QuEChERS extraction employing an acidified aqueous extraction (0.1 N HCl) with no further clean-up. Following chromatographic separation, analytes were detected using a fast polarity-switching MS/MS method that allowed both positive and negative ions to be analysed from a single injection, thus the reducing time and cost of analysis. The limits of detection and quantification ranged between 3 µg kg–1DM (aflatoxin B1, beauvericin and enniatin A and A1) and 200 µg kg–1DM (deoxynivalenol), and between 10 µg kg–1DM (aflatoxin B1, beauvericin and enniatin A1) and 500 µg kg–1DM (deoxynivalenol), respectively. Inter-assay accuracy and precision ranged between 90% and 107% and between 3.9% and 15.0% CV, respectively. The accuracy of the method was assessed through the application to a range of incurred samples in an inter-laboratory study. [ABSTRACT FROM PUBLISHER]

A method for the analytical extraction of mobile species of eightmain transformation products of 1,1-dimethylhydrazine (formaldehyde dimethylhydrazone, acetaldehyde dimethylhydrazone, 2-furaldehyde dimethylhydrazone, 1,1,4,4-tetramethyl-2-tetrazene,N,N-dimethylformamide,N-nitrosodimethylamine, 1-methyl-1H-1,2,4-triazole, and 1-formyl-2,2-dimethylhydrazine) from soils using subcritical acetonitrile at a pressure of 100 bar is proposed. The effects of temperature, number of extraction cycles, and the moisture content of soil samples on the recovery of analytes were studied. It was found that, for soils with high concentrations of lignin humic substances, efficient extraction can be attained with an addition of significant amounts of alkali to the soil (2.5 g/g). Under the optimum conditions, the recovery of analytes was higher than 70% at the extraction time no more than 30 min. A combination of the proposed sample preparation approach with analysis by gas chromatography–tandem mass spectrometry (GC-MS/MS) ensures the determination of the products of unsymmetrical dimethylhydrazine (UDMH) transformation in complex matrixes, such as soils with high concentrations of organic substance with detection limits from 1.8 to 15 µg kg–1using the direct injection of the extract into the chromatography system. The error of determination at a confidential probability of 0.95 was not worse than 15% even for analyte concentrations close to lower limit of quantitation (LLOQ) values. The method developed is a significant improvement compared to the highly efficient methods previously reported in literature differing from them with simple sample preparation, rapidity, low consumption of reagents, the possibility of simultaneous determination of eight compounds and 1–2 orders of higher sensitivity. It was successfully used for the analysis of real samples of peaty soil from the place of impact of the first step of a carrier rocket. [ABSTRACT FROM PUBLISHER]

A survey of 11 mycotoxins in 348 wheat flour samples marketed in Hebei province of China were analysed by liquid chromatography-tandem mass spectrometry, was carried out. The selected mycotoxins consisted of four aflatoxins (AFs: AFB1, AFB2, AFG1and AFG2) and sevenFusariumtoxins, i.e. deoxynivalenol (DON), nivalenol, 3-acetyldeoxynivalenol and 15-acetyldeoxynivalenol, zearalenone, Fusarenon-X and deoxynivalenol-3-glucoside. Results indicated that most of the wheat samples analysed were contaminated with mycotoxins. Wheat was most susceptible to DON (91.4% contamination), with a mean level of 240 μg kg−1. On average the probable daily intake (PDI, expressed as µg kg−1body weight day−1) of mycotoxins was within the provisional maximum tolerable daily intake (PMTDI, 2.0 µg kg−1of body weight day−1) as set by the Joint FAO/WHO Expert Committee on Food Additives. Nevertheless, exposure assessment revealed that the maximum PDI of mycotoxins was 4.06 µg kg−1body weight day−1, which was twice the PMTDI value. Thus, consistent monitoring is recommended, as to keep the contamination level under control. [ABSTRACT FROM PUBLISHER]

Context: In the recent years, there have been an increasing number of new psychoactive substances (NPS) available through marketing and sale on the Internet. The stimulant 3,4-methylenedioxypyrovalerone (MDPV) is a potent dopamine reuptake inhibitor, which can cause serious intoxications requiring intensive care and even fatality. This report from the STRIDA project presents the prevalence, laboratory results, and clinical features in a series of intoxications involving MDPV over a 5-year period.Study design: Observational case series of consecutive patients with admitted or suspected intake of NPS presented at hospitals in Sweden from 2010 to 2014.Patients and methods: Blood and/or urine samples were collected from intoxicated patients with admitted or suspected intake of NPS presenting at hospitals over the country. Analysis of NPS was performed by a liquid chromatography–tandem mass spectrometry multicomponent method. Clinical data were collected when caregivers consulted the Swedish Poisons Information Centre and also retrieved from medical records. The severity of poisoning was graded retrospectively using the poisoning severity score.Results: During the 5-year study period, the number of MDPV-related inquiries to the Poisons Information Centre was 662 out of a total ∼4500 suspected NPS-related inquiries (∼15%), and 201 analytically confirmed MDPV intoxications were enrolled in the study. The study period covered the period when the use of MDPV in Sweden was at its peak and also the decline to an almost zero level. The age range of patients was 18–68 (mean 36, median 35) years, and 71% were males. The MDPV concentrations in serum ranged between 1.0 ng/mL and 1509 ng/mL (mean 63.6, median 20) and between 1.0 ng/mL and 81 000 ng/mL (mean 3880, median 1160) in urine. The urinary values were also creatinine corrected for variation in urine dilution, and the MDPV/creatinine ratio ranged between 0.10 ng/mmol and 2480 ng/mmol (mean 247, median 92.6). There was a statistically significant association between the serum MDPV concentration and the urinary MDPV/creatinine ratio, for 118 cases where both data were available (r = 0.764;p < 0.0001, Spearman’s rank correlation). In 30 (15%) cases, MDPV was the single psychoactive substance identified in the serum or urine specimens. In the other 171 cases, other psychoactive substances were detected together with MDPV. The additional substances (n = 61) comprised of both conventional drugs of abuse, other NPS (n = 39), pharmaceuticals, and ethanol. The cathinone-derivative alpha-pyrrolidinovalerophenone (α-PVP) was the most frequent other NPS, and was detected in 58 (29%) cases, followed by methylone in 14 (7%) cases. The main clinical manifestations reported in patients testing positive for MDPV included agitation, tachycardia (≥100/min), and hypertension (systolic blood pressure ≥140 mmHg), which were observed in 130 (67%), 106 (56%), and 65 (34%) cases, respectively. Other symptoms included hallucinations (n = 31, 16%), delirium (n = 29, 15%), hyperthermia (>39°C/102.4°F;n = 18, 10%), and rhabdomyolysis (n = 16, 8%). In MDPV intoxications with serum levels >100 ng/mL, the cases were graded as more severe and hyperthermia was less common. Conclusions: In a large number of analytically confirmed MDPV intoxications from mostly polydrug users, the urine and serum MDPV concentrations showed a high variability. The clinical features were consistent with a severe sympathomimetic toxidrome. The results also demonstrated that MDPV prevailed as a drug of abuse for a long time, after its classification as a narcotic substance and despite a high incidence of severe poisonings. [ABSTRACT FROM PUBLISHER]

To investigate the process of analyte adduct formation with the components of the mobile phase in the negative electrospray ionization mode and to answer the question if the strategy of adduct identification/fragmentation is applicable for a bigger number of drugs, which meet the appropriate ionization conditions and compare the detection of appropriate analyte adducts to deprotonated analytes with tandem mass spectrometry, ten drugs containing carboxyl groups capable of negative electrospray ionization were chosen for appropriate experiments. The continuous infusion of captopril, fenbufen, gabapentin, ibuprofen, ketoprofen, naproxen, ramipril, salicylic acid, tiaprofenic acid, and 11-nor-9-carboxy-delta-9-tetrahydrocannabinol made the adduct identification/fragmentation experiments possible. The results achieved show that the adduct formation/fragmentation process can be used for LC–MS/MS analysis of drugs that meet the appropriate ionization conditions like the presence of a carboxyl group. It was also demonstrated that signal intensities achieved by the fragmentation of deprotonated drugs are in most cases higher than the signals connected with the fragmentation of appropriate adducts. [ABSTRACT FROM AUTHOR]

Endometriosis is a chronic gynecological condition that affects 10-32% of women of reproductive age and may lead to infertility. The study of protein profiles in follicular fluid may assist in elucidating possible biomarkers related to this disease. For this, follicular fluid samples were obtained from women with tubal factor or minimal male factor infertility who had pregnancy outcomes afterin vitrofertilization (IVF) treatment (control group,n = 10), women with endometriosis (endometriosis group,n = 10), along with the endometrioma from these same patients were included (endometrioma group,n = 10). For proteomic analysis, samples were pooled according to their respective groups and normalized to protein content. Proteins were analyzed by in tandem mass spectrometry (MSE) Spectra processing and the ProteinLynx Global Server v.2.5. was used for database searching. Data was submitted to the biological network analysis using Cytoscape 2.8.2 with ClueGO plugin. As a result, 535 proteins were identified among all groups. The control group differentially or uniquely expressed 33 (6%) proteins and equal expression of 98 (18%) proteins was observed in the control and endometriosis groups of which 41 (7%) proteins were further identified and/or quantified. Six (1%) proteins were observed in both the endometriosis and endometrioma groups, but 212 (39%) proteins were exclusively identified and/or quantified in the endometrioma group. There were 9 (1%) proteins observed in both the control and endometrioma groups and there were 139 (25%) proteins common among all three groups. Distinct differences among the protein profiles in the follicular fluid of patients included in this study were found, identifying proteins related to the disease progression and IVF success. Thus, some pathways related to endometriosis are associated with the presence of specific proteins, as well as the absence of others. This study provides a first step to the development of more sensitive diagnostic tests and treatment. [ABSTRACT FROM PUBLISHER]

In a 163-case series of VPD overdoses, severe valpromide poisoning has been associated with lower VPA concentrations in comparison to VPA concentrations resulting from VPA overdoses (above 200 I versus i 850 mg/L) [[3]]. To the Editor, Valpromide, a valproic acid (VPA)-derived amide, is used as antiepileptic and mood stabilizer drug. Valpromide (VPD) and valproic acid (VPA) concentrations following acute VPD overdose leading to delayed and prolonged coma. [Extracted from the article]

In this study a total of 522 samples were collected from Shandong province of China in 2014 and analysed for the occurrence of fumonisin B1 (FB1), FB2and FB3by isotope dilution ultrahigh performance liquid chromatography–tandem mass spectrometry. Fumonisins were detected in 98.1% of the corn products, with the average total level of 369.2 μg kg−1. The individual average values of FB1, FB2and FB3in corn products were 268.3, 53.7 and 47.2 μg kg−1, respectively. The simultaneous occurrence of FB1, FB2and FB3was observed in 76.7% of the corn products. Especially, the results demonstrated that the difference in the contamination levels for fumonisins in these three types of corn products was apparent. In addition, 6.2% of the wheat flour samples were contaminated with FB1, with concentrations ranging from 0.3 to 34.6 µg kg−1. No FB2or FB3was detected in wheat flour. In corn oil samples no fumonisins were detected. [ABSTRACT FROM AUTHOR]

This paper presents a cost-effective and validated multi residue confirmatory method for the determination of 167 chemically different pesticides and a survey study on Cyprus honey samples. This method uses ethyl acetate for the extraction of pesticides from honey and the determination is performed with liquid chromatography (LC) coupled to mass spectrometry (MS) operating in tandem mode (MS/MS) and with GC–ECD (gas chromatography with electron capture detector) analysis. The LC-MS/MS analytical system is especially important in the analysis of polar and non-volatile pesticides. For the validation of the method, blank honey samples were spiked with 146 pesticides (organophosphorous, carbamates, triazoles, amides, neonicodinoids, strobilurines, phenylureas, bendimidazoles and others) for the LC-MS/MS analysis at three levels: 0.01, 0.05 and 0.1 mg kg−1and with 21 pesticides for the GC-ECD analysis at two levels: 0.01 and 0.05 mg kg−1for organochlorines and 0.05 and 0.2 mg kg−1for the pyrethroids. As blank sample, a sample of honey which did not contain detectable levels of the analytes sought was used. The validation study was in accordance to the DG SANCO guidelines. The scope of validation included recovery, linearity, limits of quantification and precision. Linearity is demonstrated all along the range of concentration that was investigated with correlation coefficients ≥0.98. Recoveries of the majority of compounds were in the 70%–120% range and were characterised by precision lower or equal to 20%. The validated method was used for a survey of 36 samples of honey produced in different areas of Cyprus and this is the first work on Cypriot honey samples investigating a broad range of pesticides. Only coumaphos was detected at concentrations higher than 0.01 mg kg−1in the 58.6% of the honey samples analysed for Coumaphos. The results were evaluated in accordance to the provisions of the Commission Regulation (EU) No 37/2010 on pharmacologically active substances and their classification regarding maximum residue limits (MRLs) in foodstuffs of animal origin. The concentrations of coumaphos in all positive samples were at levels much lower than the MRL. [ABSTRACT FROM PUBLISHER]

Methamphetamine is one of the most widely used sympathomimetic amines in Asia. To identify cases of methamphetamine abuse and to estimate its abuse, hair segmental analysis is used extensively. However, existing hair analysis has several limitations due to matrix interferences. In an attempt to resolve these issues, a simple, rapid, and sensitive liquid chromatography–tandem mass spectrometry method is reported for the determination of methamphetamine and amphetamine in human hair with anion exchange solid phase extraction. Hair dissolved in sodium hydroxide was loaded on a mixed-mode anion exchange cartridge and amphetamine and methamphetamine were eluted with methanol in less than ten minutes followed by liquid chromatography–tandem mass spectrometry. The recovery of this method was between 93.9 and 102.0 percent. The limits of detection and quantitation were 0.01 and 0.05 nanograms per milligram for both analytes. The accuracy and precision were satisfactory for quantitative analysis. The suitability of the method for practical analysis was investigated using hair from methamphetamine users. [ABSTRACT FROM PUBLISHER]

A highly selective and sensitive method based on gas chromatography-tandem mass spectrometry (GC-MS/MS) to identify and quantify persistent organochlorine pesticides, (18 compounds including primary compounds and metabolites), in animal internal organs (kidneys, liver, and brain) has been developed. Tandem mass spectrometric conditions were individually optimized for each target compound in Multiple Reaction Monitoring (MRM) mode to obtain maximum sensitivity. Prior to instrumental analysis, a sample preparation method based on matrix solid phase dispersion (MSPD) followed by acidic digestion with sulfuric acid to reduce matrix co-extractives was employed. Analyses of real samples were carried out on coypus (Myocastor coypus) from the autumn slaughter of 19 animals. In the analyzed samples, three of the target compounds, namely DDE-pp′ (DDT metabolite), HCB and lindane, were detected. Their concentration levels fell in the ranges of 0.003–0.007, 0.003–0.025, and 0.003–0.021 mg kg−1(0.005, 0.010, and 0.010 mg kg−1on average) in the case of DDE-pp′, HCB and lindane, respectively. Although low quantities of organochlorine pesticides do not pose an immediate danger to consumers' health, they should be of public health concern considering long-term, low-dose exposure. [ABSTRACT FROM AUTHOR]

This study features the simultaneous extraction and quantification of 18 pharmaceuticals and personal care products (PPCPs). This is a pioneering method for the quantification of acetaminophen, sulfamethoxazole, diclofenac, atenolol, metoprolol, diethyltoluamide and oxybenzone in atmospheric pressure chemical ionisation mode. The method was validated for high repeatability and reproducibility with relative standard deviations less than 10%. Instrument quantification limits for PPCPs were within the range of 0.05–1.0 µg L−1, and the method quantification limits (MQLs) for ultrapure water were within the range of 0.3–15 ng L−1. All samples were extracted using Oasis© hydrophilic–lipophilic balanced cartridges with optimised sample size and extraction conditions. Good accuracy was demonstrated, with solid-phase extraction recoveries above 80% for most PPCPs. In environmental matrices, the MQLs for river water, sewage treatment plant (STP) effluent and STP influent were 4–25, 10–153 and 38–386.5, respectively. The method was successfully applied to investigate occurrences of persistent PPCPs in Malaysian river and sewage samples. [ABSTRACT FROM PUBLISHER]

In this study, a residue analysis method for the simultaneous determination of 107 pesticides in traditional Chinese medicines (TCMs), Angelica sinensis, A. dahurica, Leonurus heterophyllus Sweet, Pogostemon cablin and Lonicera japonica Thunb., was developed using gas chromatography coupled with tandem mass spectrometry in negative chemical ionisation mode (GC-NCI-MS/MS). NCI has advantages of high sensitivity and selectivity to chemicals with electron-withdrawing groups, and yields low background interference. For sample preparation, QuEChERS (quick, easy, cheap, effective, rugged and safe) was applied. Due to the unique characteristics of TCMs, the clean-up step was optimised by adjusting amounts of primary secondary amine, C18, graphitised carbon black and silica sorbents. Validation was mainly performed by determining analyte recoveries at four different spiking concentrations of 10, 50, 100 and 200 ng g−1, with seven replicates at each concentration. Method trueness, precision, linearity of calibration curves, lowest calibrated levels (LCLs) and matrix effects were determined to demonstrate method and instrument performance. Among the 107 pesticides tested, approximately 80% gave recoveries from 80% to 110% and < 10% relative standard deviation (RSD). The LCLs for nearly all pesticides were 5 ng g−1, and as low as 0.1 ng g−1 for dichlofenthion, endosulfan sulphate, flumetralin, isofenphos-methyl, methyl-pentachlorophenyl sulphide and trifluralin. The results indicate that GC-NCI-MS/MS is an excellent technique for quantitative and qualitative analysis of targeted GC-amenable pesticides at ultra-trace levels, especially in complex matrices such as TCMs. [ABSTRACT FROM AUTHOR]

Polyacrylate stir bar sorptive extraction (SBSE) of 2,6-dichlorobenzamide followed by liquid desorption and analysis by liquid chromatography–tandem mass spectrometry using electrospray ionization is presented. The parameters influencing the methods were optimized and included a stirring speed of 500 revolutions per minute, an extraction time of two hours, a sample volume of 15 milliliters, 30 percent NaCl, and liquid desorption using acetonitrile under ultrasonication for fifteen minutes. A reverse phase C18column was used with isocratic elution (50 percent acetonitrile and 50 percent 5 millimoles per liter aqueous ammonium acetate buffer at pH 2.4), a flow rate of 0.4 milliliter per minute, and an injection volume of 10 microliters. Quantitative analysis was carried out by multiple reaction monitoring using positive polarity. The developed method required low sample volume (15 milliliters) and provided satisfactory figures of merit with a limit of detection of 0.002 microgram per liter, a limit of quantification of 0.006 microgram per liter, and good precision (inter-day relative standard deviation below 10 percent). The polyacrylate Twister was employed for up to twenty-five extraction and liquid desorption cycles. The applicability of the method was assessed by analyzing ground water collected at five sites in North Italy. The concentrations of 2,6-dichlorobenzamide were between 0.070 and 0.282 microgram per liter. Preliminary results on the use of polar stir bars for the determination of other polar pesticides in water are also provided. [ABSTRACT FROM PUBLISHER]

An effective analytical method for the screening of mycotoxins, in indoor/outdoor airborne particulate matter, was developed and method performance data are presented. Mycotoxins are natural compounds produced, in particular conditions, as secondary metabolites by filamentous fungi and moulds, and, after their production, they can be transported far from their source. To simulate real samples, an urban dust (reference material 1649a) free from mycotoxins was used as matrix and spiked by the most common mycotoxins, chosen on the basis of studies carried out previously in other real matrices: deoxynivalenol, aflatoxin B1, ochratoxin A, T-2 toxin, zearalenone and sterigmatocystin. The analytical method was optimised and structured in four successive steps: (1) accelerated solvent extraction of the (spiked) analytes from matrix, (2) solid-phase purification (SPE) of the previous extract, (3) pre-concentration of the eluates from SPE and (4) analysis of the concentrated eluates by high performance liquid chromatography tandem mass spectrometry in multiple reaction monitoring mode. After a proper sampling campaign, the method was applied to real indoor and outdoor particulate matter samples, where the clean-up step showed to be very effective and fundamental to avoid misleading analytical results. [ABSTRACT FROM AUTHOR]

The measurement of the primary nicotine metabolites, cotinine andtrans-3′-hydroxycotinine, is a useful biomarker of nicotine exposure and metabolism genetics for smoking cessation research. Herein is described an ultra-high performance liquid chromatography–tandem mass spectrometry method for the determination of these primary nicotine metabolites in urine. Urine samples were diluted one hundred-fold with water and introduced into an ultra-high performance liquid chromatography triple quadrupole mass spectrometer using positive ion electrospray ionization with multiple reaction monitoring. Levels of urinary nicotine metabolites: cotinine,trans-3′-hydroxycotinine, and their respective glucuronides were determined directly using deuterated internal standards and compared with indirect determination by enzymatic hydrolysis. The assay was applied to a community sample of smokers’ urine (n = 280). The assay demonstrated satisfactory performance (relative standard deviation of 1.6–6.5 percent at the 1000 nanograms per milliliter level and >98 percent recovery) suitable for application to smoking studies with a run time less than five minutes. The mean (min-max) levels of cotinine and cotinine-glucuronide were 968 (31-3831) and 976 (9-5607) nanograms per milliliter. The mean (min-max) levels oftrans-3′-hydroxycotinine andtrans-3′-hydroxycotinine-glucuronide were 3529 (13-21337) and 722 (0-4633) nanograms per milliliter. Direct determination of glucuronide metabolites was superior to indirect measurement using enzymatic hydrolysis, where there was evidence of loss of metabolites during sample preparation. A sensitive and selective ultra-high performance liquid chromatography–tandem mass spectrometry assay was successfully developed for the determination of cotinine,trans-3′-hydroxycotinine, and their glucuronides in urine. The rapid and simple sample preparation makes this assay suitable for high throughput studies involving nicotine metabolism phenotype for both cytochrome P450 2A6 and uridine 5′-diphospho-glucuronosyltransferase, smoking prevalence, and cessation studies. [ABSTRACT FROM PUBLISHER]

A new HPLC–MS/MS method was developed and validated for simultaneous determination of stachydrine and leonurine (two main bioactive alkaloids) in Herba Leonuri and its succedaneum—Herba Lagopsis. Chromatographic separation was performed on an Agilent Eclipse Plus C18(100 mm × 2.1 mm, 3.5 µm) and methanol–0.1% formic acid solution (20:80) was used as a mobile phase at a flow rate of 0.2 mL/min. With positive electrospray ionization interface, the two alkaloids were detected and quantified by multiple reaction monitoring mode with the transitions of m/z 144.2.2→58.1 for stachydrine and m/z 312.2→181.1 for leonurine. The limits of detection of stachydrine and leonurine were 2.3 and 1.0 pg, respectively. The applicability of this analytical approach was confirmed by the successful analysis of the samples of the two herbs. The established method was validated to be sensitive and reliable for the determination of stachydrine and leonurine in Herba Leonuri. It was demonstrated that Herba Lagopsis also comprised stachydrine and leonurine, although their contents were all lower than Herba Leonuri samples gathered from the same areas. [ABSTRACT FROM AUTHOR]

The paralytic shellfish toxin (PST) profiles ofGymnodinium catenatumGraham have been reported for several strains from the Pacific coast of Mexico cultured under different laboratory conditions, as well as from natural populations. Up to 15 saxitoxin analogues occurred and the quantity of each toxin depended on the growth phase and culture conditions. Previous analysis of toxin profiles ofG. catenatumisolated from Mexico have been based on post-column oxidation liquid chromatography with fluorescence detection (LC-FLD), a method prone to artefacts and non-specificity, leading to misinterpretation of toxin composition. We describe, for the first time, the complete toxin profile for severalG. catenatumstrains from diverse locations of the Pacific coast of Mexico. The new results confirmed previous reports on the dominance of the less potent sulfocarbamoyl toxins (C1/2); significant differences, however, in the composition (e.g., absence of saxitoxin, gonyautoxin 2/3 and neosaxitoxin) were revealed in our confirmatory analysis. The LC-MS/MS analyses also indicated at least seven putative benzoyl toxin analogues and provided support for their existence. This new toxin profile shows a high similarity (> 80%) to the profiles reported from several regions around the world, suggesting low genetic variability among global populations. [ABSTRACT FROM PUBLISHER]

The present study developed a systematic method for the degradation products and dynamics of valtrate in artificial intestinal fluid and gastric fluid. HPLC-electrospray tandem mass spectrometry (HPLC-ESI-MSn) was applied to separate the degradation products of valtrate and identify structures of the main degradation products. Samples were separated on an Agilent Extend-Cl8by gradient elution using acetonitrile and water–acetic acid (0.25%, v/v). Analysis was performed in positive ion mode with 3000 V of capillary voltage, 40 psi of atomization pressure, 10 L min−1dry nitrogen gas velocity, and m/z 100–1000 of scan range. Six degradation products were all identified to own the stem-nucleus structures of baldrinals. Two of them were identified through the reference substances. An HPLC method with isocratic elution using acetonitrile and water (68:32, v/v) at 254 nm was established to determine content change of valtrate in artificial intestinal fluid and gastric fluid at different time points. The method was validated with good linearity in wide linear ranges (r2 = 0.9999), and good intra-day precision (RSD = 1.0%). The degradations of valtrate in artificial intestinal fluid and gastric fluid follow pseudo-first-order kinetic process, the half-life period in artificial gastric fluid is 1.73 hr, and in artificial intestinal fluid it is 1.61 hr. This study enriched the knowledge on degradation products of valtrate and may reveal the mechanism of the degradation of valtrate. [ABSTRACT FROM PUBLISHER]

Jujuboside A (JuA), a dammarane-type triterpene glycoside, is a main bioactive saponin in Zizyphi Spinosi Semen (a traditional Chinese herbal food). In this research, the distribution of JuA in Sprague-Dawley rats was investigated with a new and efficient HPLC–ESI-MS/MS method. The results showed that JuA distributed rapidly and widely in various rat tissues (including heart, liver, spleen, kidney, and lung) after intravenous administration. In addition, it was initially found that JuA could pass through the blood-brain barrier and reach various areas of the brain quickly. At 0.25 hr, the concentration of JuA in the hippocampus (204.10 ng · g−1) was significantly higher than in the cerebrum (144.27 ng · g−1), olfactory bulb (98.42 ng · g−1), and corpus striatum (76.04 ng · g−1) (p < 0.05), indicating that the hippocampus was the main accumulation area of JuA in the brain. [ABSTRACT FROM PUBLISHER]

A method for luteoskyrin in Chinese rice wine was developed using high-performance liquid chromatography–ion trap tandem mass spectrometry. The detection limit of luteoskyrin was 0.10 µg/kg. The recovery values of luteoskyrin in fortified Chinese rice wine were between 85.7% and 88.9% at levels between 0.5 µg/kg and 100 µg/kg (R > 0.999). The relative standard deviations were in the range of 1.10% to 3.20%. The method achieved rapid and accurate determination of luteoskyrin in Chinese rice wine while meeting minimum residue measurement requirements. [ABSTRACT FROM PUBLISHER]

Background. Reduced glutathione (γ-glutamylcysteinylglycine), GSH, is essential when protecting cells from oxidative stress and also an indicator of disease risk. Reported concentrations of GSH and its oxidized form, glutathione disulfide (GSSG), varies considerably, primarily due to the instability of GSH and various analytical methods. Methods. We designed a sensitive method to analyze GSH and GSSG in porcine hepatocytes using liquid chromatography-tandem mass spectrometry (LC-MS/MS) after stabilization with N-ethylmaleimide (NEM). This method includes stable isotope labeled internal standards and simple synthesis of labeled GSSG which commercial sources rarely offer. GSH and GSSG were analyzed in porcine liver biopsies giving a reference interval based on a large number of samples (26 pigs; 3 parallels). Results. The LC-MS/MS results revealed excellent linearity for both GSH and GSSG, with interday coefficient of variation (%CV) for GSH-NEM and GSSG <10 %. Accuracy for recovery tests was between 95.6% and 106.7% ( n = 3) for GSH and between 92.3% and 107.7% ( n = 3) for GSSG. The limits of quantification were 0.1 μM for GSH-NEM and 0.08 μM for GSSG. The mean concentration of GSH was 3.5 (95% CI = 1.5-8.1) mmol/liter and of GSSG 0.0023 (95% CI = 0.0003-0.019) mmol/liter. Conclusion. For the first time GSH and GSSG are analyzed in porcine hepatocytes by LC-MS/MS yielding a reference level of GSH and GSSG. The method is reproducible in any laboratory with LC-MS/MS service and will probably be applicable in all soft tissues and cell suspensions, essentially with no modification. [ABSTRACT FROM AUTHOR]

Aims. The present pilot study aimed to determine vitamin D status in Bulgarian patients with chronic HCV infection in respect to the severity of liver disease and response to interferon-ribavirin therapy. Methods. The study encompassed 296 patients: 161 males (54.4%) aged 42.08 ± 14.87 years, 135 females (45.6%) aged 45.72 ± 14.34 years, 86.5% of them infected with HCV genotype 1. Total 25-hydroxyvitamin-D (25OHD) was determined by liquid chromatography/tandem-mass spectrometric detection. Results. The median 25OHD level of the studied cohort was 50.40 nmol/L (range: 29.6-71.05). 25OHD deficient (< 25 nmol/L) were 16% of patients, 33% showed profound insufficiency (25-50 nmol/L), another 33% were in the range 50-80 nmol/L (mild insufficiency), the rest 18% were 25OHD sufficient. Significantly lower 25OHD levels were registered in cases with advanced fibrosis compared to those with mild or absent fibrosis (37.10 nmol/L vs. 53.00 nmol/L, respectively, p < 0.05). This association remained unchanged by seasonal variations in 25OHD levels. Inverse relationship was found between 25OHD and HCV-RNA ( p < 0.01). Patients with sustained virological response to therapy had significantly higher 25OHD levels, compared to patients who failed to achieve viral eradication (56.90 nmol/L vs. 45.00 nmol/L, p = 0.012). Conclusion. More than 80% of HCV-infected patients were vitamin D-deficient and -insufficient. The inverse relationship between 25OHD levels and viral load, liver fibrosis and treatment outcomes supports the hypothesis that improvement of vitamin D status may have considerable potential to amend the host defense against HCV infection and response to therapy. [ABSTRACT FROM AUTHOR]

The genusStellaria(Caryophyllaceae) presents widely distributed plants often used in traditional medicine. Flavonoids are highly active plant secondary metabolites that may be involved in some of the effects ofStellariaplants. In this study, two new high-performance liquid chromatography–electrospray ionization tandem mass spectrometry (HPLC–ESI-MS-MS) methods were developed for the determination of flavonoids and isoflavonoids in plant material. The separations were performed on a reverse-phase C18column with gradient elution using methanol and water with 0.5% acetic acid as the mobile phase. Multiple reaction monitoring was used for the tandem mass spectrometry detection and the two most intensive transitions were chosen for the identification of each analyte. The limits of detection and the limits of quantification were between 0.2 and 15.0 ng/mL and 0.6 and 50.0 ng/mL. The developed methods were successfully used for the analyses of four representatives of the genusStellaria. All the studied herbs contained luteolin and its 7-O-glycosides, naringenin, kaempferol, quercetin, its glycoside rutin, apigenin, and its 7-O-glycoside. One coumarin, scopoletin, was also found. Isoflavones were primarily represented by genistein, genistin, and ononin. Some of the analytes were detected for the first time inStellariasp. The findings support that these methods are suitable for analyses of plant material. [ABSTRACT FROM AUTHOR]

A rapid and sensitive ultra-high performance liquid chromatography–tandem mass spectrometry method was developed and validated for the determination of 6-, 8-, and 10-gingerol in the rhizomes ofZingiber officinaleRosc. The chromatographic separation was achieved isocratically on a C18(2.1 mm × 100 mm; 1.7 µm) column using acetonitrile:water (90:10 v/v) at a flow rate of 0.25 mL/min. Mass spectrometric transitions for 6-gingerol, 8-gingerol, and 10-gingerol occurred atm/z277.2467/177.1470, 305.3196/177.1617, and 333.3614/177.1666, respectively. The analysis time was 3.0 min and the elution of 6-, 8-, and 10- gingerol occurred at 1.27, 1.51, and 1.80 min. The linear dynamic range was established over the concentration range of 2 and 1000 ng/mL for the analytes. The limits of detection and quantitation for 6-gingerol, 8-gingerol, and 10-gingerol were 0.921, 0.856, and 1.069 ng/mL, and 2.951, 2.727, and 3.013 ng/mL, respectively. The relative standard deviation and accuracy were found to be satisfactory. The results showed significant variation (0.176%–0.290%w/w) in gingerols among twelve accessions and that the Patna and Lucknow varieties contained the highest concentrations and were concluded to be superior. These results may be used to devise strategies for cultivating this plant for large scale production. [ABSTRACT FROM AUTHOR]

Food poisoning may occur due to ingestion of shellfish contaminated by okadaic acid or dinophysistoxin-1 from toxic dinoflagellates. A rapid and simple method for the determination of okadaic acid and dinophysistoxin-1 is needed to identify food poisoning sources. A high performance liquid chromatography–tandem mass spectrometry (HPLC–MS) method is reported for this analysis in mussels. The separation was completed in six minutes using the selective ion monitoring mode. The limits of detection were 50 ng/mL for okadaic acid and dinophysistoxin-1, and the HPLC-MS results were in agreement with a standard bioassay. Because of its speed and sensitivity, the reported method provides a useful approach to identify sources of food poisoning. [ABSTRACT FROM AUTHOR]

We herein developed an ultra-performance liquid chromatography coupled with an electrospray ionization quadruple time-of-flight tandem mass spectrometry (UPLC/ESI-QTOF-MS) for the first time to characterize 12 iridoid glycosides fromFructus Ligustri Lucidi(FLL), a commonly used traditional Chinese medicinal herb for the treatment of kidney-deficiency and osteoporosis. In this study, a rapid and effective method was established to analyze iridoid glycosides, and 12 iridoid glycosides were detected and identified by high accurate MS data using Masslynx software. The results reveal that the iridoid glycosides were subjected to deglycosylation, major fragmentation, McLafferty rearrangement and ring cleavage, successively. Salidroside was firstly found in FLL. We have demonstrated UPLC/ESI-QTOF-MS is feasible to rapidly and reliably characterize the iridoid glycosides in FLL. [ABSTRACT FROM PUBLISHER]

High performance liquid chromatography coupled with electrospray ionization quadrupole-time-of-flight tandem mass spectrometry was used to profile the phenylethanoid glycosides inLagotis brevituba. A total of twenty-three phenylethanoid glycosides were characterized by comparing the retention time and fragmentation with standards, accurate mass measurements, and fragmentation at low and high collision energies. Most phenylethanoid glycosides were reported inL. brevitubafor the first time. This established method may be employed for comprehensive quality control ofL. brevituba. [ABSTRACT FROM AUTHOR]

A selective method for the determination of fourteen nitroimidazoles and their hydroxy-metabolites in honey was developed based on improved molecularly imprinted solid-phase extraction followed by liquid chromatography–tandem mass spectrometry. The separation of analytes was performed on a C18column using a mobile phase of 0.1% formic acid in acetonitrile and 0.1% formic acid in water with gradient elution. The method was suitable for metronidazole, hydroxymetronidazole, dimetridazole, ronidazole, hydroxydimetridazole, ipronidazole, hydroxyipronidazole, carnidazole, menidazole, nimorazole, ornidazole, secnidazole, ternidazole, and tinidazole. The procedure was evaluated according to EU Commission Decision 2002/657/EC requirements by determining linearity, specificity, recovery, repeatability, within-laboratory reproducibility, decision limit, detection capability, matrix effects, and stability. The method determined nitroimidazoles and their hydroxy-metabolites below the recommended concentration level of 3 µg kg−1. The decision limits and detection capabilities ranged from 0.110 µg kg−1to 0.387 µg kg−1and from 0.179 µg kg−1to 0.508 µg kg−1, respectively. The results from stability tests indicated that all analyzed nitroimidazoles were stable in honey stored at 4°C for at least 28 weeks and that elevated temperature and exposure to light exposure accelerated their degradation. The method was successfully applied to the analysis of a wide variety of honey samples. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine 8-hydroxydeoxyguanosine (8-OH-dG) levels in trichloroethylene (TCE)-exposed workers. Oxidative stress biomarkers and biochemical parameters were monitored among 26 TCE-exposed workers and 78 age-matched control subjects. Levels of urinary 8-OH-dG were analyzed by liquid chromatography tandem mass spectrometry. Urinary 8-OH-dG levels were significantly higher for TCE-exposed group (p< .001). Spearman's correlation test revealed positive correlations between urinary trichloroacetic acid levels and age, urinary 8-OH-dG, urinary total oxidant status, and urinary total antioxidant status (p= .042,p< .001,p< .001, andp< .001, respectively). 8-OH-dG may be a useful marker to determine the extent of TCE exposure. [ABSTRACT FROM PUBLISHER]

Numerous oxidative modifications to proteins and amino acids have been identified with most susceptible, to varying degrees, of some form of oxidative modification. The consequence of oxidation on protein structure and function reveals that some of these modifications are functionally important. The discovery and accurate characterization/description of existing and new modifications requires modern instrumentation, great care, and attention to detail, especially if the modifications are present in low stoichiometric quantities or they only exist transiently. The focus of this brief review is on the use of mass spectrometry, protein chemistry, and proteomics methods and tools to identify oxidatively modified proteins and peptides along with the characterization of specific sites. Many of the specialized mass spectrometry technologies and techniques are becoming more widely available in research laboratories with mass spectrometry or proteomics facilities allowing even non-expert researchers in the field to accurately determine modifications. Illustrative examples of some approaches are provided from the author's work, collaborative research projects, and elsewhere. [ABSTRACT FROM AUTHOR]