Simultaneous detection of amphetamine-like drugs with headspace solid-phase microextraction and gas chromatography-mass spectrometry

A headspace solid-phase microextraction and gas chromatography-mass spectrometry (HS-SPME-GC-MS) procedure for the simultaneous detection of methylen-dioxyamphetamine (MDA), methylen-dioxymethamphetamine (MDMA), methylen-dioxyethamphetamine (MDE) and N-methyl-1-(1,3-benzodioxol-5-yl)-2-butanamine (MBDB) in hair has been developed. This method is suitable for the separation of primary and secondary amines, is reproducible, is not time consuming, requires small quantities of sample and does not require any derivatization. It provides sufficient sensitivity and specificity, with limits of detection (LOD) and limits of quantitation (LOQ) for each substance of <0.7 and 1.90 ng/mg, respectively. Intra- and inter-day precision were within 2 and 10%, respectively. This method is suitable for routine clinical, epidemiological and forensic purposes and can be used for the preliminary screening of many other substances (amphetamine, methamphetamine, ketamine, ephedrine, nicotine, phencyclidine, methadone) in hair and other biological matrices such as saliva, urine and blood. We also describe the first application of this HS-SPME-GC-MS procedure to the analysis of hair and saliva samples from young people attending a disco in the Rome area. All positive hair samples were confirmed by the gas chromatography-mass-mass (GC-MS(2)) technique in positive chemical ionization (PCI) mode. Some examples of the use of the method in detecting different drugs are reported.     

Quantification of 31 volatile organic compounds in whole blood using solid-phase microextraction and gas chromatography-mass spectrometry

The prevalence of exposure to volatile organic compounds (VOCs) has raised concern about possible health effects resulting from chronic human exposure. To support studies exploring the relation between VOC exposure and health effects, we developed an automated analytical method using solid-phase microextraction (SPME), capillary gas chromatography (GC), and quadrupole mass spectrometry (MS). This method quantifies trace levels (low parts per trillion) of 14 halogenated alkanes, 5 halogenated alkenes, 10 aromatic compounds, and 2 other VOCs in human blood. Detection limits for the SPME-GC-MS method range from 0.005 to 0.12 microg/L, with linear calibration curves spanning three orders of magnitude. The improved throughput of this method will enable us to expand biomonitoring efforts to assess nonoccupational VOC exposure in large epidemiological studies.     

Investigation of volatile biomarkers in lung cancer blood using solid-phase microextraction and capillary gas chromatography-mass spectrometry

In the present work, solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) was developed for investigation of lung cancer volatile biomarkers. Headspace SPME conditions (fiber coating, extraction temperature and extraction time) and desorption conditions were optimized and applied to determination of volatiles in human blood. To find the biomarkers of lung cancer, investigation of volatile compounds in lung cancer blood and control was performed by using the present method. Concentrations of hexanal and heptanal in lung cancer blood were found to be much higher than those in control blood. The two molecules of hexanal and heptanal were regarded as biomarkers of lung cancer. By comparison of volatiles in breath and in blood, it is demonstrated that hexanal and heptanal in breath were originated from blood and screening of lung cancer by breath analysis be feasible. These results show that SPME/GC-MS is a simple, rapid and sensitive method very suitable for investigation of volatile disease markers in human blood.     

Simultaneous determination of selegiline and desmethylselegiline in human body fluids by headspace solid-phase microextraction and gas chromatography-mass spectrometry

A method for the simultaneous determination of selegiline and its metabolite, desmethylselegiline, in human whole blood and urine is presented. The method, which combines a fiber-based headspace solid-phase microextraction (SPME) technique with gas chromatography-mass spectrometry (GC-MS), required optimization of various parameters (e.g., salt additives, extraction temperatures, extraction times and the extraction properties of the SPME fiber coatings). Pargyline was used as the internal standard. Extraction efficiencies for both selegiline and desmethylselegiline were 2.0-3.4% for whole blood, and 8.0-13.2% for urine. The regression equations for selegiline and desmethylselegiline extracted from whole blood were linear (r(2)=0.996 and 0.995) within the concentration ranges 0.1-10 and 0.2-20 ng/ml, respectively. For urine, the regression equations for selegiline and desmethylselegiline were linear (r(2)=0.999 and 0.998) within the concentration ranges 0.05-5.0 and 0.1-10 ng/ml, respectively. The limit of detection for selegiline and desmethylselegiline was 0.01-0.05 ng/ml for both samples. The lower and upper limits of quantification for each compound were 0.05-0.2 and 5-20 ng/ml, respectively. Intra- and inter-day coefficients of variation for selegiline and desmethylselegiline in both samples were not greater than 8.7 and 11.7%, respectively. The determination of selegiline and desmethylselegiline concentrations in Parkinson's disease patients undergoing continuous selegiline treatment is presented and is shown to validate the present methodology.     

Analysis of Rhioxma Curcumae Aeruginosae volatiles by solid-phase microextraction with gas chromatography-mass spectrometry

In this paper, a headspace solid-phase microextraction (HS-SPME) method was applied to analyse the volatile compounds in a traditional Chinese medicine (TCM), Rhioxma Curcumae Aeruginosae. SPME parameters such as fibers, extraction temperature, extraction time and desorption time were investigated. Thirty-five volatile compounds were separated and identified. Relative standard deviations (RSDs) were less than 8.4%, showing that the method has a good reproducibility. The volatile constituents were also analyzed by steam distillation (SD) and thirty-seven compounds were identified. The similar results obtained by the two methods showed that SPME is a good alternative for the analysis of volatile constituents in Rhioxma Curcumae Aeruginosae samples and it is a relatively simple, rapid and solvent-free method.     

Determination of metaldehyde in human serum by headspace solid-phase microextraction and gas chromatography-mass spectrometry

A rapid headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) method has been developed for the determination of metaldehyde in human serum samples. Metaldehyde is extensively used as a molluscicide for the control of slugs and snails, and cases of metaldehyde poisoning have been reported. Metaldehyde was headspace-extracted on a polydimethylsiloxane (PDMS) fiber at 70 degrees C for 25 min, desorbed, and analyzed rapidly by GC-MS. The method was validated for limit of detection (LOD), linearity, precision, and recovery. Although the recovery of the sample was very low, the method itself was rapid with a low detection limit of 0.25 microg/ml, R.S.D. value 12.6%, and linearity range 0.5-25.0 microg/ml (r(2)=0.999). The results demonstrated that the SPME-GC-MS method for the analysis of metaldehyde is simple, rapid, solvent-free, and does not require any pre-analysis conversions.     

Determination of cocaine and cocaethylene in plasma by solid-phase microextraction and gas chromatography-mass spectrometry

The present paper describes a method for the simultaneous determination of cocaine and cocaethylene in plasma. It was based in the extraction of the analytes by solid-phase microextraction (SPME), and gas chromatography-mass spectrometry (GC-MS) was used to identify and quantify the analytes in selected ion monitoring (SIM) mode. The method showed to be very simple, rapid and sensitive. The method was validated for the two compounds, including linearity (range 25-1000 ng/mL) and the main precision parameters. It was applied to ten plasma samples from cocaine and alcohol users, obtaining positive results in all cases.     

Sol-gel-based solid-phase microextraction and gas chromatography-mass spectrometry determination of dextromethorphan and dextrorphan in human plasma

A novel solid-phase microextraction (SPME) method was developed for isolation of dextromethorphan (DM) and its main metabolite dextrorphan (DP) from human plasma followed by GC-MS determination. Three different polymers, poly(dimethylsiloxane) (PDMS), poly(ethylenepropyleneglycol) monobutyl ether (Ucon) and polyethylene glycol (PEG) were synthesized as coated fibers using sol-gel methodologies. DP was converted to its acetyl-derivative prior to extraction and subsequent determination. The porosity of coated fibers was examined by SEM technique. Effects of different parameters such as fiber coating type, extraction mode, agitation method, sample volume, extraction time, and desorption condition, were investigated and optimized. The method is rapid, simple, easy and inexpensive and offers high sensitivity and reproducibility. The limits of detection are 0.010 and 0.015 ng/ml for DM and DP, respectively. The precisions for both analytes are below 5% (n=5). The correlation coefficient was satisfactory (r(2)>0.99) for both DM and DP. Linear ranges were obtained from 0.03 ng/ml to 2 microg/ml for DM and from 0.05 ng/ml to 2 microg/ml for DP.     

Determination of quinalphos in blood and urine by direct solid-phase microextraction combined with gas chromatography-mass spectrometry

A new method based on direct solid-phase microextraction (DI-SPME) followed by gas chromatography-mass spectrometry was developed for the purpose of determining quinalphos in blood and urine. Two types of coated fibre have been assayed and compared: carbowax/divinylbenzene (CW/DVB 65 microm) and polydimethylsiloxane (PDMS 100 microm). The main parameters affecting the SPME process such as temperature, salt addition, pH, stirring and adsorption/desorption time profiles were optimized to enhance the sensitivity of the procedure. The method was developed using only 100 microL of blood and urine. Limits of detection of the method for blood and urine matrices were, respectively, 10 and 2 ng/mL. Linearity was established over concentration ranges from 0.05 to 50 microg/mL for blood, and 0.01 to 50 microg/mL for urine, with regression coefficients ranging between 0.9991 and 0.9999. Intra- and interday precision values were less than 13%, and accuracy was within +/-15% of the nominal concentration for all studied levels in both matrices. Absolute recoveries were 14 and 26% for blood and urine, respectively.     

Rapid screening procedure based on headspace solid-phase microextraction and gas chromatography-mass spectrometry for the detection of many recreational drugs in hair

An increasing number of synthetic drugs are appearing on the illicit market and on the scene of drug use by youngsters. Official figures are underestimated. In addition, immunochemical tests are blind to many of these drugs and appropriate analytical procedures for routine clinical and epidemiological purposes are lacking. Therefore, the perceived increasing abuse of recreational drugs has not been proved yet. In a previous paper, we proposed a procedure for the preliminary screening of several recreational substances in hair and other biological matrices. Unfortunately, this procedure cannot apply to cocaine. Consequently, we performed a new headspace solid-phase microextraction and gas chromatography-mass spectrometry (HS-SPME-GC-MS) procedure for the simultaneous detection of cocaine, amphetamine (A), methamphetamine (MA), methylen-dioxyamphetamine (MDA), methylen-dioxymethamphetamine (MDMA), methylen-dioxyethamphetamine (MDE), N-methyl-1-(1,3-benzodioxol-5-yl)-2-butanamine (MBDB), ketamine, and methadone in human hair. Hair was washed with water and acetone in an ultrasonic bath. A short acid extraction with 1M hydrochloric acid was needed; the fiber was exposed to a 5 min absorption at 90 degrees C and thermal desorption was performed at 250 degrees C for 3 min. The procedure was simple, rapid, required small quantities of sample and no derivatization. Good linearity was obtained over the 0.1-20.0 ng/mg range for the target compounds. Sensitivity was good enough: limits of detection (LOD) were 0.7 ng/mg of hair for the majority of substances. The intra-day precision ranged between 7 and 20%. This paper deals with the analytical performance of this procedure and its preliminary application to hair samples obtained on a voluntary basis from 183 young people (138 males and 45 females) in the Rome area.     

Performance evaluation of a wood-chip based biofilter using solid-phase microextraction and gas chromatography-mass spectroscopy-olfactometry

A pilot-scale mobile biofilter was developed where two types of wood chips (western cedar and 2 in. hardwood) were examined to treat odor emissions from a deep-pit swine finishing facility in central Iowa. The biofilters were operated continuously for 13 weeks at different air flow rates resulting in a variable empty bed residence time (EBRT) from 1.6 to 7.3 s. During this test period, solid-phase microextraction (SPME) PDMS/DVB 65 microm fibers were used to extract volatile organic compounds (VOCs) from both the control plenum and biofilter treatments. Analyses of VOCs were carried out using a multidimentional gas chromatography-mass spectrometry-olfactometry (MDGC-MS-O) system. Results indicated that both types of chips achieved significant reductions in p-cresol, phenol, indole and skatole which represent some of the most odorous and odor-defining compounds known for swine facilities. The results also showed that maintaining proper moisture content is critical to the success of wood-chip based biofilters and that this factor is more important than media depth and residence time.     

Simultaneous determination of barbiturates in human biological fluids by direct immersion solid-phase microextraction and gas chromatography-mass spectrometry

Simultaneous determination of seven barbiturates in human whole blood and urine by combining direct immersion solid-phase microextraction (DI-SPME) with gas chromatography-mass spectrometry (GC-MS) is presented. The main parameters affecting the DI-SPME process, such as SPME fibers, salt additives, pHs, extraction temperatures and immersion times were optimized for simultaneous determination of the drugs. The extraction efficiencies were 0.0180-0.988 and 0.0156-2.76% for whole blood and urine, respectively. The regression equations of the drugs showed excellent linearity for both samples; the correlation coefficients (r(2)) were 0.994-0.999. The detection limits for whole blood were 0.05-1 microg x ml(-1), and those for urine 0.01-0.6 microg x ml(-1). Actual quantitation could be made for pentobarbital in whole blood and urine obtained from volunteers, who had been orally administered a therapeutic dose of the drug. The DI-SPME/GC-MS procedure for barbiturates established in this study is simple and sensitive enough to be adopted in the fields of clinical and forensic toxicology.     

Rapid determination of acetone in human plasma by gas chromatography-mass spectrometry and solid-phase microextraction with on-fiber derivatization

Acetone is an important volatile disease marker. Due to its nature of activity and volatility, it is a difficult task to measure the concentration of acetone in biological samples with accuracy. In this paper, we developed a novel method for determination of trace amount acetone in human plasma by solid-phase microextraction technique with on-fiber derivatization. In this method, the poly(dimethylsiloxane)/divinylbenzene (PDMS/DVB) fiber was used and O-2,3,4,5,6-(pentafluorobenzyl) hydroxylamine hydrochloride (PFBHA) was first loaded on the fiber. Acetone in plasma sample was agitated into headspace and extracted by solid-phase microextraction (SPME) fiber and subsequently derivatized with PFBHA on the fiber. Acetone oxime was analyzed by gas chromatography-mass spectrometry (GC-MS). Quantitative analysis of acetone in plasma was carried out by using external standard method. The SPME conditions (extraction temperature and time) and the method validation were studied. The present method was tested by determination of acetone in diabetes plasma and normal plasma. Acetone concentration in diabetes plasma was found to be higher than 1.8mM, while in normal plasma was lower than 0.017 mM. The results show that the present method is a potential tool for diagnosis of diabetes.     

Determination of cocaine, benzoylecgonine and cocaethylene in human hair by solid-phase microextraction and gas chromatography-mass spectrometry

The present work describes a highly precise and sensitive method developed to detect cocaine (COC), benzoylecgonine (BE, its main metabolite) and cocaethylene (CE, transesterification product of the coingestion of COC with ethanol) in human head hair samples. The method was based on an alkylchloroformate derivatization of benzoylecgonine and the extraction of the analytes by solid-phase microextraction (SPME). Gas chromatography-mass spectrometry (GC-MS) was used to identify and quantify the analytes in selected ion monitoring mode (SIM). The limits of quantification and detection (LOQ and LOD) were: 0.1 ng/mg for COC and CE, and 0.5 ng/mg for BE. Good inter- and intra-assay precision was observed. The dynamic range of the assay was 0.1-50 ng/mg. The method is not time consuming and was shown to be easy to perform.     

Chemical diagnosis of Lesch-Nyhan syndrome using gas chromatography-mass spectrometry detection

Lesch-Nyhan syndrome (LNS) is caused by a severe deficiency of hypoxanthine-guanine phosphoribosyltransferase (HPRT) and clinically characterized by self-injurious behavior and nephrolithiasis; the latter is treatable with allopurinol, an inhibitor of xanthine oxidase which converts xanthine and hypoxanthine into uric acid. In the HPRT gene, more than 200 different mutations are known, and de novo mutation occurs at a high rate. Thus, there is a great need to develop a highly specific method to detect patients with HPRT dysfunction by quantifying the metabolites related to this enzyme. A simplified urease pretreatment of urine, gas chromatography-mass spectrometry, and stable isotope dilution method, developed for cutting-edge metabonomics, was further applied to quantify hypoxanthine, xanthine, urate, guanine and adenine in 100 microl or less urine or eluate from filter-paper-urine strips by additional use of stable isotope labeled guanine and adenine as the internal standards. In this procedure, the recoveries were above 93% and linearities (r(2)=0.9947-1.000) and CV values (below 7%) of the indicators were satisfactory. In four patients with proven LNS, hypoxanthine was elevated to 8.4-9.0 SD above the normal mean, xanthine to 4-6 SD above the normal mean, guanine to 1.9-3.7 SD, and adenine was decreased. Because of the allopurinol treatment for all the four patients, their level of urate was not elevated, orotate increased, and uracil was unchanged as compared with the control value. It was concluded that even in the presence of treatment with allopurinol, patients with LNS can be chemically diagnosed by this procedure. Abnormality in the levels of hypoxanthine and xanthine was quite prominent and n, the number of standard deviations above the normal mean, combined for the two, was above 12.9.     

光肩星天牛幼虫虫粪挥发物成分分析

天牛幼虫排出的虫粪所释放的挥发性物质成为天敌搜寻天牛所在微栖境的重要化学信息物质.本试验采用固相微萃取技术,提取光肩星天牛Anoplophora glabripennis(Motschulsky)取食垂柳和金丝柳后产生虫粪的挥发性物质,利用气相色谱-质谱联用仪(GC-MS)进行鉴定.结果表明,虫粪挥发性物质主要为萜烯类物质.两种虫粪挥发物中含共有物质19种,其中à-蒎烯的含量最高,该物质在垂柳虫粪挥发物中相对含量为51.60%,在金丝柳虫粪中的相对含量为28.84%.在金丝柳虫粪中检测到的挥发物种类稍多于垂柳虫粪中检测到的种类.     

Use of solid-phase microextraction followed by on-column silylation for determining chlorinated bisphenol A in human plasma by gas chromatography-mass spectrometry

In this study, a solid-phase microextraction (SPME) method based on poly(acrylate)-coated fibres has been developed for detection and quantification of chlorinated bisphenol A in human plasma due to the need for an assessment of human exposure to them. After desorption of the analytes for 7 min at 300 degrees C, they were directly derivatized in the GC injector port by injection of 2 microL of diluted bis(trimethylsilyl)trifluoroacetamide (BSTFA). The formation of trimethylsilylate derivatives improves the selectivity, sensitivity and performance of the chromatographic properties obtained when the analytes are directly separated. Quantification was carried out using single-ion monitoring (SIM). The respective chloroderivative molecular ions appear at 406, 440, 474 and 508 m/z; whereas the base peaks corresponding to a loss of a methyl group in all cases appear at 391, 425, 459 and 493 m/z for mono-, di-, tri- and tetrabisphenol A, respectively. Deuterated bisphenol A (BPA-d16) was used as an internal standard. The method was applied to the determination of Cl-BPA, Cl2-BPA, Cl3-BPA and Cl4-BPA at very low concentration levels in plasma. Recovery efficiencies were close to 100% in all cases.     

Analysis of cantharidin in false blister beetles (Coleoptera: Oedemeridae) by headspace solid-phase microextraction and gas chromatography-mass spectrometry

A headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography-mass spectrometry (GC-MS) method was developed to determine a type of terpenoid named as cantharidin in the false blister beetles, family Oedemeridae. The experimental parameters for HS-SPME method were optimized. Six commercial fibers for HS-SPME method development were tested and the divinylbenzene/carboxene/polydimethylsiloxane fiber was selected to provide the best detection of analyzed compound. The calibration curve showed linearity in the range of 0.1-50 μg mL(-1), correlation coefficient (R(2)=0.992), limit of detection (0.01 ng mL(-1)) and quantitation (0.04 ng mL(-1)) were obtained for the proposed method. The relative standard deviations of intra-day and inter-day assays were 7.8 and 3.4%, respectively. The recovery values, obtained after spiking the beetle samples by three concentration levels of standard solution, were higher than 87%. The results indicated the successful application of the proposed method on the analysis of cantharidin from the false blister beetles.     

High-temperature solid-phase microextraction procedure for the detection of drugs by gas chromatography–mass spectrometry

High-temperature headspace solid-phase microextraction (SPME) with simultaneous (“in situ”) derivatisation (acetylation or silylation) is a new sample preparation technique for the screening of illicit drugs in urine and for the confirmation analysis in serum by GC–MS. After extraction of urine with a small portion of an organic solvent mixture (e.g., 2 ml of hexane–ethyl acetate) at pH 9, the organic layer is separated and evaporated to dryness in a small headspace vial. A SPME-fiber (e.g., polyacrylate) doped with acetic anhydride–pyridine (for acetylation) is exposed to the vapour phase for 10 min at 200°C in a blockheater. The SPME fiber is then injected into the GC–MS for thermal desorption and analysis. After addition of perchloric acid and extraction with n-hexane to remove lipids, the serum can be analysed after adjusting to pH 9 as described for urine. Very clean extracts are obtained. The various drugs investigated could be detected and identified in urine by the total ion current technique at the following concentrations: amphetamines (200 μg/l), barbiturates (500 μg/l), benzodiazepines (100 μg/l), benzoylecgonine (150 μg/l), methadone (100 μg/l) and opiates (200 μg/l). In serum all drugs could be detected by the selected ion monitoring technique within their therapeutic range. As compared to liquid–liquid extraction only small amounts of organic solvent are needed and larger amounts of the pertinent analytes could be transferred to the GC column. In contrast to solid-phase extraction (SPE), the SPME-fiber is reusable several times (as there is no contamination by endogenous compounds). The method is time-saving and can be mechanised by the use of a dedicated autosampler.