Simultaneous screening of estrogens,progestogens, and phenols and their metabolites in potable water and river water by ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry

In this study, a method employing ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was developed to simultaneously screen for 36 endocrine-disrupting chemicals (EDCs; e.g., estrogens, progestogens, phenols, and their metabolites) both in potable and river water. From the selected compounds, 21 target compounds, for which reference standards were available, were used as model compounds for method development and optimization. The other target compounds, for which reference standards were unavailable, were investigated in post-target analysis on the basis of their theoretical molecular masses. The solid-phase extraction and chromatographic separation steps were optimized. For this method, limits of detection for the target compounds were less than 0.72 ng L^? 1, and the overall recoveries varied between 46% and 134% with relative standard deviations ranging from 7% to 35%. The mass errors between theoretical and experimental mass for all resulting precursor and characteristic fragment ions ranged from ? 1.9 to 2.8 mDa. The method developed was successfully used to analyze the composition of potable and river water in Shanghai City; in addition, some compounds of interest (estriol, estrone, and bisphenol A) were identified accurately. Further, a post-target analysis was performed and an estrogen metabolite was hypothesized in the water samples due to the excellent sensitivity of the method in full-spectrum acquisition mode and the valuable accurate mass information in MS and tandem MS mode. Therefore, UPLC-Q-TOF-MS has proven to be a powerful technique for wide-scope screening and identification of relevant EDCs in environmental water sources.     

Effects of propyphenazone and other non-steroidal anti-inflammatory agents on the synthetic and endogenous androgenic anabolic steroids urinary excretion and/or instrumental detection

This paper describes the effects of oral administration of non-steroidal anti-inflammatory drugs on the endogenous and synthetic anabolic androgenic steroids urinary excretion as assessed by gas-chromatography mass-spectrometry. Experiments were carried out on 5 male subjects, with pathologies and/or diseases, treated with non-steroidal anti-inflammatory drugs. To set up the individual baseline variability of testosterone and its main metabolites, urine samples were collected for 3 days, every 2 h prior to the administration of the drug(s); whereas the study of the effects of a single dose of each drug, here considered, on the endogenous androgen steroid urinary concentrations, was assessed by collecting urine samples for 2 days, every 2 h. Data obtained after drugs administration were then evaluated taking into account the individual baseline variability. The results showed that, only in the case of propyphenazone administration, the relative urinary concentrations of some testosterone metabolites were significantly altered. More specifically, the urinary levels of dehydroepiandrosterone, 11keto-etiocholanolone, 11β-hydroxyandrosterone, 11β-hydroxyetiocholanolone, androsterone, etiocholanolone and some metabolite ratios decrease significantly, generally between 2 and 10 h after administration of the drug, whereas no effects were observed on urinary calculated concentrations of testosterone, epitestosterone, 5α-androstane-3α,17β-diol, 5β-androstane-3α,17β-diol and testosterone/epitestosterone ratio. The observed effects do not depend on alterations on pharmacokinetics (excretion/metabolism), but on steroid sample preparation steps (hydrolysis and derivatization) inhibition. More specifically the significant decrease of dehydroepiandrosterone and testosterone metabolites urinary levels was due to a reduced yield of the steroid derivatization step for the presence in urine of the main metabolites of propyphenazone, namely hydroxyl-propyphenazone metabolites.     

Development and validation of an LC-MS/MS method for profiling 39 urinary steroids (estrogens,androgens, corticoids,and progestins)

Abnormal production or metabolism of steroid hormones is responsible for the development of endocrine diseases. Thus, accurate quantification of steroid hormones is needed for both research into clinical conditions and diagnostic and monitoring purposes. An improved analytical method for profiling 39 steroids in urine using LC–MS/MS was developed. As a pre-treatment procedure prior to LC–tandem mass spectrometry (LC–MS/MS) analysis, hydrolysis using β-glucuronidase and solid-phase extraction for purifying the samples were performed. Steroids were separated using Waters ACQUITY BEH C₁₈ column (2.1 × 100 mm, 1.7 μm) and a mobile phase consisting of eluent A (0.01% formic acid and 1 mm ammonium formate in water) and eluent B (0.01% formic acid and 1 mm ammonium formate in methanol) with a gradient program at a flow rate of 0.4 mL/min. Under the optimized method, the linearity of calibration curves was higher than 0.992. The limits of detection at signal-to-noise ratio of 3 were 0.03–90 ng/mL. The developed novel LC–MS/MS method can quantitatively profile 39 steroids in a single analytical run. Steroid profiling based on quantitative results could improve the diagnosis and monitoring of hormone-dependent diseases.     

Highly sensitive and selective analysis of urinary steroids by comprehensive two-dimensional gas chromatography combined with positive chemical ionization quadrupole mass spectrometry

Comprehensive two dimensional gas chromatography (GC × GC) provides greater separation space than conventional GC. Because of fast peak elution, a time of flight mass spectrometer (TOFMS) is the usual structure-specific detector of choice. The quantitative capabilities of a novel GC × GC fast quadrupole MS were investigated with electron ionization (EI), and CH(4) or NH(3) positive chemical ionization (PCI) for analysis of endogenous urinary steroids targeted in anti-doping tests. Average precisions for steroid quantitative analysis from replicate urine extractions were 6% (RSD) for EI and 8% for PCI-NH(3). The average limits of detection (LODs) calculated by quantification ions for 12 target steroids spiked into steroid-free urine matrix (SFUM) were 2.6 ng mL(-1) for EI, 1.3 ng mL(-1) for PCI-CH(4), and 0.3 ng mL(-1) for PCI-NH(3), all in mass scanning mode. The measured limits of quantification (LOQs) with full mass scan GC × GC-qMS were comparable with the LOQ values measured by one-dimensional GC-MS in selected ion monitoring (SIM) mode. PCI-NH(3) yields fewer fragments and greater (pseudo)molecular ion abundances than EI or PCI-CH(4). These data show that a benchtop GC × GC-qMS system has the sensitivity, specificity, and resolution to analyze urinary steroids at normal urine concentrations, and that PCI-NH(3), not currently available on most GC × GC-TOFMS instruments, is of particular value for generation of structure-specific ions.     

Identification and profiling of targeted oxidized linoleic acid metabolites in rat plasma by quadrupole time‐of‐flight mass spectrometry

Linoleic acid (LA) and LA‐esters are the precursors of LA hydroperoxides, which are readily converted to 9‐ and 13‐hydroxy‐?octadecadienoic acid (HODE) and 9‐ and 13‐oxo‐?octadecadienoic acid (oxo ODE) metabolites in vivo. These four oxidized LA metabolites (OXLAMs) have been implicated in a variety of pathological conditions. Therefore, their accurate measurement may provide mechanistic insights into disease pathogenesis. Here we present a novel quadrupole time‐of‐flight mass spectrometry (Q‐TOFMS) method for quantitation and identification of target OXLAMs in rat plasma. In this method, the esterified OXLAMs were base‐hydrolyzed and followed by liquid–liquid extraction. Quantitative analyses were based on one‐point standard addition with isotope dilution. The Q‐TOFMS data of target metabolites were acquired and multiple reaction monitoring extracted‐ion chromatograms were generated post‐acquisition with a 10 ppm extraction window. The limit of quantitation was 9.7–35.9 nmol/L depending on the metabolite. The method was reproducible with a coefficient of variation of <18.5%. Mean concentrations of target metabolites in rat plasma were 57.8, 123.2, 218.1 and 57.8 nmol/L for 9‐HODE, 13‐HODE, 9‐oxoODE and 13‐oxoODE, respectively. Plasma levels of total OXLAMs were 456.9 nmol/L, which correlated well with published concentrations obtained by gas chromatography/mass spectrometry (GC/MS). The concentrations were also obtained utilizing a standard addition curve approach. The calibration curves were linear with correlation coefficients of >0.991. Concentrations of 9‐HODE, 13‐HODE, 9‐oxoODE and 13‐oxoODE were 84.0, 138.6, 263.0 and 69.5 nmol/L, respectively, which were consistent with the results obtained from one‐point standard addition. Target metabolites were simultaneously characterized based on the accurate Q‐TOFMS data. This is the first study of secondary LA metabolites using Q‐TOFMS. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.     

Analysis of erlotinib and its metabolites in rat tissue sections by MALDI quadrupole time-of-flight mass spectrometry

A qualitative and quantitative analysis of erlotinib (RO0508231) and its metabolites was carried out on rat tissue sections from liver, spleen and muscle. Following oral administration at a dose of 5 mg/kg, samples were analyzed by matrix-assisted laser desorption ionization (MALDI) with mass spectrometry (MS) using an orthogonal quadrupole time-of-flight instrument. The parent compound was detected in all tissues analyzed. The metabolites following drug O-dealkylation could also be detected in liver sections. Sinapinic acid (SA) matrix combined with the dried-droplet method resulted in better conditions for our analysis on tissues. Drug quantitation was investigated by the standard addition method and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis on the tissue extracts. The presence of the parent compound and of its O-demethylated metabolites was confirmed in all tissue types and their absolute amounts calculated. In liver the intact drug was found to be 3.76 ng/mg tissue, while in spleen and muscle 6- and 30-fold lower values, respectively, were estimated. These results were compared with drug quantitation obtained by whole-body autoradiography, which was found to be similar. The potential for direct quantitation on tissue sections in the presence of an internal standard was also investigated using MALDI-MS. The use of alpha-cyano-4-hydroxycinnamic acid (CHCA) as the matrix resulted in better linearity for the calibration curves obtained with reference solutions of the drug when compared to SA, but on tissue samples no reliable quantitative analysis was possible owing to the large variability in the signal response. MS imaging experiments using MALDI in MS/MS mode allowed visualizing the distribution of the parent compound in liver and spleen tissues. By calculating the ratio between the total ion intensities of MS images for liver and spleen sections, a value of 6 : 1 was found, which is in good agreement with the quantitative data obtained by LC-MS/MS analysis.     

Investigation of potential toxic components based on the identification of Genkwa Flos chemical constituents and their metabolites by high‐performance liquid chromatography coupled with a Q Exactive high‐resolution benchtop quadrupole Orbitrap mass spectrometer

Genkwa Flos, a famous traditional Chinese medicine has been reported to have significant hepatotoxicity. A high‐throughput and reliable method was established to explore potential toxic components by high‐performance liquid chromatography coupled with a Q Exactive high‐performance benchtop quadrupole‐Orbitrap mass spectrometer. A total of 68 compounds including 22 chemical components and 46 metabolites were tentatively identified based on the accurately measured mass value, retention time, and fragmentation pattern. Besides, the metabolic pathways of main components in Genkwa Flos were also illustrated. The results indicated that hydroxylation, demethylation, methylation, glucuronidation, sulfation, cysteine conjugation, and glutathione conjugation participated in the metabolic reactions of Genkwa Flos. Moreover, 12 Genkwa Flos chemical components and 26 metabolites were detected in cell lysate, which were considered as the bound components to HL‐7702 cells. In view of cell affinity theory, these compounds were preliminarily deduced to be potential toxic ingredients for the hepatotoxicity induced by Genkwa Flos. The results demonstrated that the developed method was a very feasible and efficient approach for the components identification even in the complex matrix. In conclusion, this study will provide a deep insight into the toxic substances of Genkwa Flos and lay a chemical basis for in‐depth toxic studies on Genkwa Flos hepatotoxicity.     

Simultaneous determination of the urinary metabolites of benzene, toluene, xylene and styrene using high-performance liquid chromatography/hybrid quadrupole time-of-flight mass spectrometry

A simple and rapid method using reversed-phase liquid chromatography/tandem mass spectrometry (LC/MS/MS) for the simultaneous determination of the urinary metabolites of benzene, toluene, xylene and styrene in human urine specimens and standard solutions is described. A hybrid quadrupole/time-of-flight (QqTOF) mass spectrometer was compared for the determination of metabolite of aromatic solvents in urine samples. The metabolites selected were: trans,trans-muconic acid, hippuric acid, o-, m- and p-methylhippuric acid and phenylglyoxylic acid. The compounds were well separated from each other on narrow-bore 1-mm i.d. reversed-phase LC C-18 columns. Average recoveries for loading 100 microL of urine samples varied from 88-110% and the quantification limits were less than 30 ng/mL for each analyte (3 ng/mL for trans,trans-muconic acid). The qualitative information obtained (mass accuracy, resolution and full-scan spectra) with the QqTOF mass spectrometer allows a secure identification of analytes in biological matrices.     

Rapid and sensitive analysis of phthalate metabolites, bisphenol A, and endogenous steroid hormones in human urine by mixed-mode solid-phase extraction, dansylation, and ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry

Steroid hormone levels in human urine are convenient and sensitive indicators for the impact of phthalates and/or bisphenol A (BPA) exposure on the human steroid hormone endocrine system. In this study, a rapid and sensitive method for determination of 14 phthalate metabolites, BPA, and ten endogenous steroid hormones in urine was developed and validated on the basis of ultra-performance liquid chromatography coupled with electrospray ionization triple quadrupole mass spectrometry. The optimized mixed-mode solid phase-extraction separated the weakly acidic or neutral BPA and steroid hormones from acidic phthalate metabolites in urine: the former were determined in positive ion mode with a methanol/water mobile phase containing 10 mM ammonium formate; the latter were determined in negative ion mode with a acetonitrile/water mobile phase containing 0.1 % acetic acid, which significantly alleviated matrix effects for the analysis of BPA and steroid hormones. Dansylation of estrogens and BPA realized simultaneous and sensitive analysis of the endogenous steroid hormones and BPA in a single chromatographic run. The limits of detection were less than 0.84 ng/mL for phthalate metabolites and less than 0.22 ng/mL for endogenous steroid hormones and BPA. This proposed method had satisfactory precision and accuracy, and was successfully applied to the analyses of human urine samples. This method could be valuable when investigating the associations among endocrine-disrupting chemicals, endogenous steroid hormones, and relevant adverse outcomes in epidemiological studies.

Characterization of prednisone, prednisolone and their metabolites by gas chromatography-mass spectrometry

Human urinary metabolites of the synthetic corticosteroids prednisone and prednisolone were detected in the course of gas chromatographic steroid profiling as methoxime-trimethylsilyl derivatives. Metabolites were provisionaly identified by combined gas chromatography-mass spectrometry. The major metabolites were 11-keto/11-hydroxy conversion products, 20-hydroxy and 4,5-dihydro analogues of the parent drugs. Cortisone, 6-hydroxy and fully saturated A-ring compounds were minor metabolites. Retention indices and mass spectral data are presented.     

Determination of 13C/12C ratios of endogenous urinary steroids: method validation, reference population and application to doping control purposes

The application of a comprehensive gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS)-based method for stable carbon isotopes of endogenous urinary steroids is presented. The key element in sample preparation is the consecutive cleanup with high-performance liquid chromatography (HPLC) of underivatized and acetylated steroids, which allows the isolation of ten analytes (11beta-hydroxyandrosterone, 5alpha-androst-16-en-3beta-ol, pregnanediol, androsterone, etiocholanolone, testosterone, epitestosterone, 5alpha-androstane-3alpha,17beta-diol, 5beta-androstane-3alpha,17beta-diol and dehydroepiandrosterone) from a single urine specimen. These steroids are of particular importance to doping controls as they enable the sensitive and retrospective detection of steroid abuse by athletes.Depending on the biological background, the determination limit for all steroids ranges from 5 to 10 ng/mL for a 10 mL specimen. The method is validated by means of linear mixing models for each steroid, which covers repeatability and reproducibility. Specificity was further demonstrated by gas chromatography/mass spectrometry (GC/MS) for each analyte, and no influence of the sample preparation or the quantity of analyte on carbon isotope ratios was observed. In order to determine naturally occurring (13)C/(12)C ratios of all implemented steroids, a reference population of n = 61 subjects was measured to enable the calculation of reference limits for all relevant steroidal Delta values.     

Analysis of dexamethasone,triamcinolone, and their metabolites in human urine by microcolumn liquid and capillary gas chromatography mass spectrometry

Adult male volunteers were administered orally 10 mg of the espective drug. Urine samples were investigated by micro-column liquid chromatography and capillary gas chromatography combined with on-line mass spectrometry. The former technique was found to be usable for the detection of these drugs. The latter method appeared to be superior in terms of sensitivity and for metabolism studies. The major excretion products of dexamethasone were identified as isomeric 6-hydroxy metabolites. Dexamethasone as such and its 20-hydroxy metabolite were found in minor quantities. Unlike dexamethasone, triamcinolone is excreted largely unchanged from the human body. Two metabolites were identified as 11-keto and 4,5-dihydrotriamcinolone. With the gas chromatography methods developed, abuse of these drugs can be detected up to 24 h after administration of a 5 mg single dose.     

Multi-residue analysis of 206 pesticides in grass forage by the one-step quick,easy, cheap,effective, rugged,and safe method combined with ultrahigh-performance liquid chromatography quadrupole orbitrap mass spectrometry

A novel method for detecting pesticide multi-residue in grass forage (alfalfa and oat) was established based on the one-step automatic extraction and purification technology of quick, easy, cheap, effective, rugged, and safe combined with ultrahigh-performance liquid chromatography quadrupole Orbitrap high-resolution mass spectrometry. The crushed sample was extracted with acetonitrile with 1% acetate, followed by a cleanup step with a primary-secondary amine, octadecylsilane, and graphitized carbon black. The extraction and purification were carried out using the one-step automatic pretreatment equipment. The target pesticides were acquired in positive ion electrospray ionization mode and full scan/data dependent secondary scan mode. The calibration curve shows good linearity over the corresponding concentration range, with the coefficient of determination greater than 0.99. The screening detection limits were 0.5–50 μg/kg, and the limit of quantification for the 206 pesticides was set at 1–50 μg/kg. At the spiking levels of one, two, and 10 times of limit of quantification, more than 95% of pesticides had recovery between 70–120%, with a relative standard deviation ≤20%. The method was proved to be simple, rapid, high-sensitivity, and could be routinely used for the high throughput screening and quantitative analysis of pesticide residues in alfalfa and oat.     

Analysis of endogenous steroids in urine by means of multi-immunoaffinity chromatography and isotope ratio mass spectrometry for sports drug testing

Analytical and Bioanalytical Chemistry - Detecting the administration of naturally occurring but synthetically derived steroids (e.g., testosterone) in routine doping controls is particularly...     

超高效液相色谱-三重四极杆质谱法快速同时测定牛奶中53种β-内酰胺类抗生素及其代谢产物的残留

建立了超高效液相色谱-三重四极杆质谱快速测定牛奶中53种β-内酰胺类抗生素及其代谢产物残留的检测方法。牛奶样品经等量乙腈沉淀去蛋白、超滤后,以0.1%(v/v,下同)甲酸水溶液和0.1%甲酸乙腈溶液作为流动相进行梯度洗脱,在ACQUITY BEH C18色谱柱上实现分离,一次进样分析仅需10 min,正离子电喷雾多反应监测(MRM)模式检测,基体工作曲线内标法定量。线性范围从方法的定量限至200μg/kg,相关系数均优于0.991 1,平均加标回收率在71%~121%之间,相对标准偏差为1.7%~19%(n=6)。方法简单、快速,每人每天可处理50多份样品,检出限能够满足我国和欧盟对兽药残留的最高限量要求,适合于牛奶样品中53种β-内酰胺类抗生素及其代谢产物的快速筛查和定量测定。     

LC/MS/MS analysis of the endogenous dimethyltryptamine hallucinogens,their precursors,and major metabolites in rat pineal gland microdialysate

We report a qualitative liquid chromatography–tandem mass spectrometry (LC/MS/MS) method for the simultaneous analysis of the three known N,N‐dimethyltryptamine endogenous hallucinogens, their precursors and metabolites, as well as melatonin and its metabolic precursors. The method was characterized using artificial cerebrospinal fluid (aCSF) as the matrix and was subsequently applied to the analysis of rat brain pineal gland‐aCSF microdialysate. The method describes the simultaneous analysis of 23 chemically diverse compounds plus a deuterated internal standard by direct injection, requiring no dilution or extraction of the samples. The results demonstrate that this is a simple, sensitive, specific and direct approach to the qualitative analysis of these compounds in this matrix. The protocol also employs stringent MS confirmatory criteria for the detection and confirmation of the compounds examined, including exact mass measurements. The excellent limits of detection and broad scope make it a valuable research tool for examining the endogenous hallucinogen pathways in the central nervous system. We report here, for the first time, the presence of N,N‐dimethyltryptamine in pineal gland microdialysate obtained from the rat. Copyright © 2013 John Wiley & Sons, Ltd.     

High-resolution analysis by nano-electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry for the identification of molecular species of phospholipids and their oxidized metabolites

Nano-electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) was applied to identify the molecular species of phosphatidylethanolamine of Caenorhabditis elegans, which has a high concentration of phospholipids with a fatty acyl chain having an odd number of carbon atoms. The molecular species of diacyl phosphatidylethanolamine with one fatty acyl chain having an odd number of carbon atoms and one fatty acyl chain having an even number of carbon atoms was identified separately from alkyl-acyl phosphatidylethanolamine with an alkyl chain having an even number of carbon atoms and a fatty acyl chain having an even number of carbon atoms. Furthermore, nano-ESI-FTICRMS was applied to the direct identification of oxidized phosphatidylcholine from soybean. The mass peaks of individual molecular species of oxidative phosphatidylcholine, such as 34:3 diacyl phosphatidylcholine with peroxide (+2O) (m/z 788.544) or 34:2 diacyl phosphatidylcholine with peroxide (+2O) (m/z 790.560), can be separated from the peaks of the molecular species of the non-oxidative phospholipids. This suggests that the mass peaks with a difference of less than 0.1 mass units in their molecular weight can be separated and that their individual exact molecular compositions can be obtained by the FTICRMS analysis. The high resolution and high accuracy of FTICRMS are very effective in the analysis of molecular species of phospholipids and their derivatives.     

Identification and quantification of urinary benzo[a]pyrene and its metabolites from asphalt fume exposed mice by microflow LC coupled to hybrid quadrupole time-of-flight mass spectrometry

Prolonged, extensive exposure to asphalt fume has been associated with several adverse health effects. Inhaled polycyclic aromatic hydrocarbons (PAHs) from asphalt fume exposure have been suspected of inducing such effects. In this study, a bioanalytical method was proposed and evaluated to identify and quantify benzo[a]pyrene and its hydroxy-metabolites. This method is based on coupling a microflow liquid chromatography (LC) to a hybrid quadrupole orthogonal acceleration time-of-flight mass spectrometry (Q-TOFMS). In the experiment, thirty-two B6C3FI mice were exposed to asphalt fume in a whole body inhalation chamber for 10 days (4 h day(-1)) and twelve other mice were used as controls. The asphalt fume was generated at 180 degrees C and the concentrations in the animal exposure chamber ranged 175-182 mg m(-3). Benzo[a]pyrene and its metabolites of 3-hydroxybenzo[a]pyrene, benzo[a]pyrene-7,8-dihydrodiol(+/-), benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide(+/-), and benzo[a]pyrene-7,8,9,10-tetrahydrotetrol(+/-) in the urine of asphalt fume exposed mice were identified and found at 3.18 ng 100 mL(-1), 31.36 ng 100 mL(-1), 11.56 ng 100 mL(-1), 54.92 ng 100 mL(-1), and 45.23 ng 100 mL(-1) respectively. The results revealed that the urinary benzo[a]pyrene and its hydroxy-metabolites from exposed mice were at significantly higher levels (p < 0.001) than those from the control groups. Compared with several other technologies such as HPLC-UV and HPLC-fluorescence, the new method is more sensitive and selective, and it can also provide additional useful information on the structures of the metabolites. Hence, this method can be used to perform the assessment and to study the mechanisms of the adverse health effects. The fragmentation patterns established in this study can also be used to identify and quantify PAH metabolites in other biological fluids.