BACKGROUND: Salivary steroid measurements have the potential to provide a non-invasive assessment of serum free steroid concentrations. Salivary testing has been proposed as a possible substitute for serum testing partly because of easy sample collection. METHODS: We developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for simultaneous measurement of testosterone ...

This study builds on a series of investigations characterizing substances in kraft mill chemical recovery condensates that depress sex steroids in fish. Here, incubations of goldfish testis androgen receptors (AR) with condensate extracts were used to investigate the potential role of androgens in hormone depressions. Condensates contained variable levels of ...

The natural occurrence of endogenous anabolic steroids together with their availability in different administration forms makes the detection of their misuse a great challenge for doping control laboratories. Nowadays, the detection of endogenous steroids abuse is performed by the analysis of the steroid profile. Recently, androst-1,4-dien-3,17-dione (1,4-AD), androst-4,6-dien-3,17-dione (4,6-AD), 17β-hydroxy-androst-4,6-dien-3-one ...

Objective: The measurement of serum testosterone (T) in women is challenging due to lack of trueness, precision and sensitivity of various available T assays. Accurate assessment of T in women is crucial especially in conditions associated with alleged over- or underproduction of T, such as in polycystic ovary syndrome (PCOS) ...

This paper describes the application of catechin-modified titanium dioxide nanoparticles (TiO(2) NPs) as matrices to analyze four steroid hormones by surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS). The catechin-modified TiO(2) NPs have high absorbance at 337nm and are effective SALDI matrices when using a nitrogen laser. Four test steroid hormones-cortisone, hydrocortisone, ...

Androstenedione (4-androstene-3,17-dione) is banned by the World Anti-Doping Agency (WADA) as an endogenous steroid. The official method to confirm androstenedione abuse is isotope ratio mass spectrometry (IRMS). According to the guidance published by WADA, atypical steroid profiles are required to trigger IRMS analysis. However, in some situations, steroid profile parameters ...

We developed and validated a method to measure steroid hormones with liquid chromatography-tandem mass spectrometry (LC-MS/MS) in faecal samples of white-faced capuchins. The method includes the measurement of adrenal and gonadal hormones such as cortisol, testosterone, estrone, progesterone and a number of their faecal metabolites. This method can be used ...

A first step towards the multidetection, identification and quantification of anabolic androgenic steroids by enzyme-linked immunosorbent assay (ELISA) has been performed in this study. This proposal combines multiple competitive ELISA assays with different cross-reactivity profiles and multivariate data analysis techniques. Data have been analyzed by principal component analysis in conjunction ...

A reliable, convenient, and sensitive on-line sweeping-MEKC sample concentration technique has been applied for the simultaneous separation of six steroids including two pairs of epimer with 10mM phosphate buffer (pH 7.0) that contains 80mM sodium dodecyl sulfate (SDS), 14mM β-cyclodextrin (β-CD), and 4% (v/v) methanol. The column length was 105cm ...

Circadian disruption can have several possible health consequences, but is not well studied. In order to measure circadian disruption, in relation to shift or night work, we developed a simple and sensitive method for the simultaneous determination of melatonin, cortisol and testosterone in human saliva. We used liquid-liquid extraction (LLE) ...

Ultra-performance liquid chromatography coupled to mass spectrometry (UPLC/MS) has been used increasingly for measuring changes of low molecular weight metabolites in biofluids/tissues in response to biological challenges such as drug toxicity and disease processes. Typically samples show high variability in concentration, and the derived metabolic profiles have a heteroscedastic noise ...

Steroid hormone concentrations are mostly determined by using different body fluids as matrices and applying immunoassay techniques. However, usability of these approaches may be restricted for several reasons, including ethical barriers to invasive sampling. Therefore, we developed an ultra-performance LC-MS-MS method for high-throughput determination of concentrations of cortisol, cortisone, dehydroepiandrosterone ...

A rapid and high-throughput isotope dilution LC-MS/MS method with online sample pre-concentration and clean-up using anionic mixed-mode SPE was described for the determination of closantel and rafoxanide in edible bovine and ovine tissues. Tissue samples were extracted with acetonitrile and acetone mixture (60:40, v/v). Sample pre-concentration, clean-up and analysis were ...

A novel design of solid phase microextraction fiber containing carbon nanotube reinforced sol-gel which was protected by polypropylene hollow fiber (HF-SPME) was developed for pre-concentration and determination of BTEX in environmental waste water and human hair samples. The method validation was included and satisfying results with high pre-concentration factors were ...

A selective and sensitive HILIC-MS/MS method for the simultaneous quantification of nicotine and its metabolites in human maternal and cord sera was developed and validated. After solid-phase extraction, LC separation was achieved on a hydrophilic interaction chromatography. The validated method is capable of selective identification as well as accurate and ...

The accurate measurement of free analyte concentrations within complex sample matrixes by pre-equilibrium solid-phase microextraction (SPME) has proven challenging due to variations in mass uptake kinetics. For the first time, the effects of the sample binding matrix and tortuosity on the kinetics of analyte extraction (from the sample to the ...

Electromembrane extraction (EME) was used as an off-line sample pre-treatment method for the determination of heavy metal cations in aqueous samples using CE with capacitively coupled contactless conductivity detection (CE-C(4) D). A short segment of porous polypropylene hollow fibre was penetrated with 1-octanol and 0.5% v/v bis(2-ethylhexyl)phosphonic acid and constituted a ...

A capillary electroseparation technique for focusing and selective pre-concentration of metal chelates with subsequent on-line isotachophoresis (ITP) analysis was developed and verified. The ions of alkali earth metals (Mg, Ca, Sr, and Ba) were pre-concentrated from the mixture and analyzed. The focusing of the metals was carried out in a ...

(1)H NMR metabolic profiling of urine, serum and plasma has been used to monitor the impact of the pre-analytical steps on the sample quality and stability in order to propose standard operating procedures (SOPs) for deposition in biobanks. We analyzed the quality of serum and plasma samples as a function ...

Air sampling for (1 → 3)-β-d-glucan may be a good method for assessing inhalation exposure to airborne fungi. Pre-sampling contamination of filter media used for sampling (1 → 3)-β-d-glucan may lead to substantial exposure measurement errors. Using the Limulus amebocyte lysate assay, we tested for pre-sampling levels of (1 → ...

This article presents the first application of gold nanoparticles deposited capillaries as pre-concentration devices for in-capillary microextraction CZE and their use for the analysis of monohydroxy-polycyclic aromatic hydrocarbons in synthetic urine samples. The successful separation of 1-hydroxypyrene, 9-hydroxyphenanthrene, 3-hydroxybenzo[a]pyrene (3-OHbap), 4-hydroxybenzo[a]pyrene and 5-hydroxybenzo[a]pyrene under a single set of electrophoretic conditions ...

An improved chemical strategy for processing of the generator produced (68)Ga was developed based on processing of the original (68)Ge/(68)Ga generator eluate on a micro-column. Direct pre-concentration and purification of the eluted (68)Ga is performed on a cation-exchange resin in hydrochloric acid/acetone media. A supplementary step based on a second ...

Perinatal asphyxia is a leading cause of brain injury in infants, occurring in 2-4 per 1000 live births. The clinical response to asphyxia is variable and difficult to predict with current diagnostic tests. Reliable biomarkers are needed to help predict the timing and severity of asphyxia, as well as response ...

A new sol-gel protocol was designed and optimized to produce titanium-dioxide-based columns within confined geometries such as monolithic capillary columns and porous-layer open-tubular columns. A surface pre-treatment of the capillary enabled an efficient anchorage of the monolith to the silica capillary wall during the synthesis. The monolith was further synthesized ...

Microstructuring of polydimethylsiloxane (PDMS) is a key step for many lab-on-a-chip (LOC) applications. In general, the structure is generated by casting the liquid prepolymer against a master. The production of the master in turn calls for special equipment and know how. Furthermore, a given master only allows the reproduction of ...

The study of metabolites (metabolomics) is increasingly being applied to investigate microbial, plant, environmental and mammalian systems. One of the limiting factors is that of chemically identifying metabolites from mass spectrometric signals present in complex datasets. Three workflows have been developed to allow for the rapid, automated and high-throughput annotation ...

Oleanolic acid (OA) and ursolic acid (UA) are the ubiquitous triterpenic acids in plant kingdom and have multiple biological effects. In the present study, a highly sensitive and selective method using a dual-sensitive probe 2-(5-benzoacridine)ethyl-p-toluenesulfonate (BAETS) as pre-column labeling reagent has been developed for rapid determination of the triterpenes OA ...

During the mineralisation of metal carbonates MCO3 (M=Ca, Sr, Ba, Mn, Cd, Pb) liquid-like amorphous intermediates emerge. These intermediates that form via a liquid/liquid phase separation behave like a classical emulsion and are stabilized electrostatically. The occurrence of these intermediates is attributed to the formation of highly hydrated networks whose ...

Both pre- and post-column oxidation liquid chromatography methods with fluorescence detection are available for detecting paralytic shellfish toxins. Each method has been evaluated in multiple laboratories and validated as a potential alternative to the mouse bioassay. This communication compares the advantages and limitations of both methods. For a given laboratory, ...

The positive role and application of highly accurate mass measurements in proteomics is well documented. The new generation of hybrid FTMS and Q-TOF instruments, including the LTQ-Orbitrap (OT), is remarkable in their ability to routinely produce single-digit to subppm statistical mass accuracy while maintaining high analytical sensitivity. The use of ...

A monolithic molecularly imprinted polymer (MIP) column was prepared as the stationary phase for the capillary electrochromatographic (CEC) separation of a group of structurally related compounds including dopamine (DA), (±)-epinephrine (EP), (-)-isoproterenol (ISO), (±)-norepinephrine (NE), (±)-octopamine (OCT), and (±)-synephrine (SYN). Here, (-)-NE was used as the template. Either methacrylic acid ...

The increasing availability and use of sports supplements is of concern as highlighted by a number of studies reporting endocrine disruptor contamination in such products. The health food supplement market, including sport supplements, is growing across the Developed World. Therefore, the need to ensure the quality and safety of sport ...

In the present work, an improved and direct approach for the preparation of molecularly imprinted polymers (MIPs) was proposed. The MIPs were prepared based on bulk polymerization by water-bath heating and ultrasonic elution of the template, using rutin as the template, acrylamide (AM) as the functional monomer and 2,2'-azobisisobutyronitrile (AIBN) ...

Monolithically integrated, polymer (SU-8) microchips comprising an electrophoretic separation unit, a sheath flow interface, and an electrospray ionization (ESI) emitter were developed to improve the speed and throughput of metabolism research. Validation of the microchip method was performed using bufuralol 1-hydroxylation via CYP450 enzymes as the model reaction. The metabolite, ...

This paper revises the derivatization approaches for the determination of biogenic amines in wines. Since most of these amines display poor spectroscopic features to be detected by UV absorption or emission (fluorescence) spectroscopy, derivatization is necessary to attain the desired sensitivity. Reagents such as o-phthaldialdehyde, fluorenylmethylchloroformate, dansyl-Cl and dabsyl-Cl have ...

Ion filters based on planar DMS can be integrated with the inlet configuration of most mass spectrometers, and are able to enhance the quality of mass analysis and quantitative accuracy by reducing chemical noise, and by pre-separating ions of similar mass. This paper is the first in a series of ...

Amphetamine (AP) and amphetamine-type stimulants, methamphetamine (MA) and N,N-dimethylamphetamine (DMA), are known as central nervous system stimulants, and their abuse throughout the world has recently increased. Since it is difficult to physically distinguish among AP, MA and DMA, analysts may not be aware of what abusers have administered. In this ...

A new separation and quantification method using ultra high-performance liquid chromatography (UHPLC) with UV detection was developed for the detection of sibiromycin in fermentation broth of Streptosporangium sibiricum. The solid phase extraction method based on cation-exchange was employed to pre-concentrate and purify fermentation broth containing sibiromycin prior to UHPLC analysis. ...

Tobacco smoking constitutes a significant source of indoor air pollution. Various chemical compounds that are emitted during tobacco smoking can have a direct cytotoxic effect on spermatozoa by damaging DNA. There is some evidence that tobacco smoking in men could affect male fertility. The goals of this study were to ...

Drop-to-drop solvent microextraction (DDSME) coupled with matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) for quantitative determination of nicotinic acid in one drop of urine sample has been proposed. All parameters, such as type of organic solvent, extraction time, exposure volume solvent, pH of the sample solution that affecting the separation ...

Consumption of nicotine in the form of smokeless tobacco (snus, snuff, chewing tobacco) or nicotine-containing medication (gum, patch) may benefit sport practice. Indeed, use of snus seems to be a growing trend and investigating nicotine consumption amongst professional athletes is of major interest to sport authorities. Thus, a liquid chromatography-tandem ...

A simple, sensitive, and inexpensive singe-drop microextraction (SDME) followed by gas chromatography and flame-ionization detection (GC-FID) was developed for determination of nicotine, anabasine, and cotinine in human urine and saliva samples. The target compounds were extracted from alkaline aqueous sample solution into an organic acceptor drop suspended on the tip ...

The consumption of psychostimulant amphetamine-like drugs has increased significantly in recent years. Some MDMA metabolites are probably involved in the neurotoxicity and neurodegeneration caused by prolonged use rather than MDMA itself. We recently developed a method to analyze MDMA and its five main metabolites in rat plasma [7]. We have ...

This overview covers the different chemometric strategies linked to chromatographic methodologies that have been used and presented in the recent literature to cope with problems related to incomplete separation, the presence of unexpected components in the sample, matrix effect and changes in the analytical signal due to pre-treatment of sample. ...

CE with capacitively coupled contactless conductivity detection (C(4)D) was employed for the separation and detection of seven amphetamine analogues as well as amphetamine, dextroamphetamine, methamphetamine and 3,4-methylenedioxymethamphetamine. The separation electrolyte was 30 mM hydroxypropyl-beta-cyclodextrin (HPbetaCD) in a 75 mM acetic acid+25 mM sodium acetate buffer adjusted to pH 4.55. Conductivity ...

Nicotine can be determined in pharmaceuticals and biological fluids by micellar liquid chromatography (MLC) using a C18 column, a mobile phase containing sodium dodecyl sulphate 0.15M-6% (v/v) pentanol-NaH(2)PO(4) 0.01 M (pH 6)-KCl 0.001 M, with electrochemical detection at 0.8 V. In the optimization step, the influence of the modifiers propanol, ...

A simple, sensitive, selective, and reproducible method based on high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry was developed for the determination of nicotine and its major metabolite cotinine in human urine. The internal standard (acetaminophen) was separated from cotinine on a Hypersil Gold C(18) column with retention times of 9.3 and ...

Famprofazone, a major ingredient of Gewolen, is an analgesic that has been demonstrated to be metabolized to methamphetamine (MA) and amphetamine (AM) following administration. Therefore, a famprofazone user may be interpreted as an illicit MA abuser in Taiwan because the user's urine tested positive for MA. The purpose of this ...

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for determining four tobacco-specific N-nitrosamines (TSNAs) in mainstream smoke from Chinese Virginia cigarettes was developed. Mainstream cigarette smoke particulate matter was collected on a Cambridge filter pad, further extracted using 100 mM ammonium acetate after 100 microL internal standard addition, and subsequently analyzed ...

A method of hollow fiber (HF) liquid phase microextraction (LPME) combined with gas chromatography (GC)-flame ionization detection (FID) was developed for the simultaneous quantification of trace amphetamine (AP), methamphetamine (MA), methylenedioxyamphetamine (MDA), methylenedioxymethamphetamine (MDMA), caffeine and ketamine (KT) in drug abuser urine samples. The factors affecting on the extraction of ...