Biomedical subjects

M P Giménez

Publications and source records attributed to M P Giménez.

6 recordsLinked to original sources

PubMed2004

Diagnosis of chronic alcohol consumption. Hair analysis for ethyl-glucuronide.

This paper describes a procedure for the detection and quantification of ethyl-glucuronide (EtG) in hair samples. During method development the efficacy of extraction of EtG from hair was compared in four extraction methods: (a) methanol; (b) methanol:water (1:1); (c) water; and (d) water:trifluoroacetic acid (9:1). In addition, three derivatizing agents were compared as well: N,O-bistrimethylsilyl-trifluoroacetamide (BSTFA): trimethylchlorosilane (TMCS) (99:1), pentafluoropropionic anhydride (PFPA) and heptafluorobutyric anhydride (HFBA). Water was found to be the best extracting solvent and PFPA the best derivatizing agent. Both provided the highest recoveries, with cleaner extracts and more stable derivatives. The final method is as follows: about 100mg of hair are sequentially washed with water and acetone. The decontaminated sample is finely cut with scissors, then the deuterated internal standard (EtG-d5) and 2 mL of water are added. After sonication for 2 h, the sample is maintained at room temperature overnight. Derivatization is performed with PFPA. Derivatives are injected into a GC-MS system in the electronic impact mode. The method shows linearity over the range of concentrations from 0.050 to 5 ng/mg. Detection and quantification limits are 0.025 and 0.050 ng/mg, respectively. Mean recoveries for the three studied concentrations (low, medium and high) are higher than 87%. The coefficients of variation in intra- and inter-assay precision are always lower than 7%. The method is being routinely applied in our lab for the diagnosis of chronic alcohol consumption.

Alcoholism↗

PubMed2003

Tissue concentrations of MDMA and its metabolite MDA in three fatal cases of overdose.

The recreational use of amphetamine derivatives has become increasingly popular in our country in past recent years. Their use is especially common among young people participating in dance parties known as "raves." As a direct consequence of their increased use, the number of fatal cases in which these compounds have been involved have increased dramatically since the second half of the last decade. In our laboratory, we have registered 25 cases related to amphetamine derivatives use since 1996. Three of them were deeply studied and the results obtained are presented in this paper. This information may be useful for the interpretation of the results obtained in toxicological analysis in the cases in which death may be attributed to MDMA use.

3,4-Methylenedioxyamphetamine↗

PubMed1995

Simultaneous quantification of opiates, cocaine and cannabinoids in hair.

The present paper describes a sensitive method developed in our laboratory for the simultaneous analysis of opiates (morphine, codeine and monoacetylmorphine), cocainis (cocaine and benzoylecgonine) and cannabinoids (delta 9-tetrahydrocannabinol and 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid) in hair samples. After decontaminating the sample with dichloromethane, two consecutive hydrolyses were performed in order to achieve the best conditions for extracting the three kinds of drugs from the protein matrix. First the opiate and cocainic compounds were extracted by means of a soft acidic hydrolysis with 0.1 N HCl at 50 degrees C overnight and organic solvent extraction at pH 9.2. The cannabinoids need a stronger basic hydrolysis with 11.8 N KOH for 10 min at laboratory temperature. After adding maleic acid, the cannabinoids were extracted with an organic solvent. The derivatization was carried out with heptafluorobutyric anhydride and hexafluoropropanol. Calibration curves were linear between 0.5-100 ng/mg of hair. Recovery and reproducibility were assured. The quantification limits ranged between 0.04-0.26 ng/mg of hair. Seventy hair samples from known drug abusers were cut into 1-cm segments and analyzed by this method. The ranges of measured concentrations (ng/mg) were 0.31-89 for cocaine, 0.1-5.76 for benzoylecgonine, 0.34-45.79 for morphine, 0.45-39.59 for codeine, 0.09-48.18 for monoacetylmorphine, 0.06-7.63 for THC and 0.06-3.87 for THC-COOH. The results of sectional analyses agreed with the self reported drug histories. The usefulness of this method is in assessing earlier drug consumption, and also at the same time obtaining a chronological profile of the consumption of these three types of drugs.

Cannabinoids↗

PubMedDate not supplied

Rapid analysis of amphetamine, methamphetamine, MDA, and MDMA in urine using solid-phase microextraction, direct on-fiber derivatization, and analysis by GC-MS.

A rapid, sensitive, and solvent-free procedure for the simultaneous determination of amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), and 3,4-methylenedioxymethamphetamine (MDMA) in urine was developed using solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) in the selected ion monitoring mode. A headspace vial containing the urine sample, NaOH, NaCl, and amphetamine-d3 as the internal standard was heated at 100 degrees C for 20 min. A polydimethylsiloxane fiber was maintained in the vial headspace for 10 min in order to adsorb the amphetaminic compounds, which were subsequently derivatized by exposing the fiber to trifluoroacetic anhydride for 20 min in the headspace of another vial maintained at 60 degrees C for 20 min. The trifluoroacetyl derivatives were desorbed in the GC injection port for 5 min. Several parameters were considered during the method optimization process. These included a comparison of SPME with or without headspace, the required derivatization procedure, and the influence of temperature on the headspace extraction and derivatization methods. The optimized method was validated for the four compounds tested. Calibration curves showed linearity in the range 50-1000 ng/mL (r = 0.9946-0.9999). Recovery data were 71.89-103.24%. The quantitation limits were 10 ng/mL for amphetamine and methamphetamine and 20 ng/mL for MDA and MDMA. All of these data recommend the applicability of the method for use in the analytical routine of a forensic laboratory.

3,4-Methylenedioxyamphetamine↗

PubMedDate not supplied

Determination of benzodiazepines by derivative spectroscopy.

In this work, a rapid method is described for the quantitative determination of benzodiazepines, by means of derivative spectroscopy, and the application of this technique towards the study of the aforementioned substances in biological fluids. Diazepam, chlordiazepoxide, nitrazepam and clorazepate may be identified and quantitated at concentrations of 0.2 mg/L or greater.

Adult↗

PubMedDate not supplied

New method for determination of ten pesticides in human blood.

An analytical method was developed for precise identification and quantitation of 10 pesticides in human blood. The pesticides studied, which have appeared frequently in actual cases, were endosulfan, lindane, parathion, ethyl-azinphos, diazinon, malathion, alachlor, tetradifon, fenthion and dicofol (o-p' and p-p' isomers). The current method replaces an earlier method which involved liquid-liquid extraction with a mixture of n-hexane-benzene (1 + 1). The extraction is performed by solid-phase extraction, with C18 cartridges and 2 internal standards, perthane and triphenylphosphate. Eluates were analyzed by gas chromatography (GC) with nitrogen-phosphorus and electrochemical detectors. Results were confirmed by GC-mass spectrometry in the electron impact mode. Blood blank samples spiked with 2 standard mixtures and an internal standard were used for quantitation. Mean recoveries ranged from 71.83 to 97.10%. Detection and quantitation limits are reported for each pesticide. Examples are provided to show the application of the present method to actual samples.

Calibration↗