Wide-bore capillary column gas chromatography in toxicological analysis of biological samples from multidrug overdoses fatalities

Fatalities from multidrug overdoses account for 25% of the total number of all poisoning fatalities and as such deserve greater attention from researchers than single drug overdoses. High resolution, good sensitivity, and repeatability provided by gas chromatography (GC) with wide-bore capillary silica and glass columns make GC particularly useful for identification and quantitative analysis of drugs in toxicological screening of autopsy specimens. Results of toxicological findings in three deaths from multidrug overdoses (methaqualone, doxepine, methotrimeprazine, pernazine-aspirin, paracetamol, codeine-morphine, diazepam) occurring in routine medical practice are reported.     

Forensic applications of pyrolysis capillary gas chromatography

A simple system of pyrolysis capillary gas chromatography has been used to improve discrimination and long-term reproducibility in the analysis of polymers particularly alkyd based paints typically encountered in forensic casework. This involved the coupling of a Pye Curie-point pyrolyser to the inlet port of a capillary gas chromatograph operated in the splitless mode. Examples of pyrograms demonstrating improved differentiation of alkyd paints, and also examples of other architectural and automotive paints, automobile rubbers, adhesives, polyurethane foams and fibres are shown.     

Analysis of amphetamines by supercritical fluid chromatography,high-performance liquid chromatography,gas chromatography and capillary zone electrophoresis; a preliminary comparison

A supercritical fluid chromatographic method with UV detection (SFC–UV) for the quantitative separation of phenylisothiocyanate (PITC)-derivatised amphetamines is described and compared to high-performance liquid chromatography–diode array detection (HPLC–DAD), gas chromatography–flame ionisation detection (GC–FID) and capillary zone electrophoresis–diode array detection (CZE–DAD) analyses of amphetamine and related compounds. Difficulties in the analysis of common amphetamines by SFC are discussed. Of the methods described in this paper, the SFC method offered the greatest sensitivity at 0.01–0.02 μg of drug on column. Suggestions are made for the use of combinations of these techniques for the identification of amphetamines when gas chromatography–mass spectrometry is not available.     

Determination of benzodiazepines in human hair by on-line high-performance liquid chromatography using a restricted access extraction column.

A method is described for the identification of five frequently prescribed benzodiazepines (BZD) (clonazepam, diazepam, flunitrazepam, midazolam and oxazepam) in human hair samples by reversed phase HPLC, following on-line simple enrichment and clean-up on a restricted access extraction column. 50mg of powdered hair were incubated (2h at 45 degrees C) after sonication (1h) in 1 ml of the following solution (methanol:ammonia, 97.5/2.5, v/v). The aliquot was centrifuged and the methanolic phase transferred to a conical tube and evaporated under a gentle stream of nitrogen. The residue was reconstituted by adding 100 microl of a mixture of phosphate buffer (20mM, pH=2.2) and acetonitrile (94/6, v/v). A total of 80 microl were injected into the system with the column switching technique. The pre-column or clean-up column was washed with phosphate buffer pH=7.2. The drugs retained on the pre-column were then eluted in the back-flush mode and separated on a C(8) semi micro column, Lichrospher select B, 125 mm x 3 mm. The BZD were determined by a photodiode-array detector at 254 nm, using reference data (retention time and UV spectra) stored in a personal library. The method showed excellent linearity between 0.5 and 20 ng/mg of hair for clonazepam, flunitrazepam and midazolam and between 0.5 and 100 ng/mg of hair for diazepam and oxazepam. Finally, the present method has been applied to a number of forensic cases in our laboratory.     

A simple, rapid and simultaneous analysis of complex volatile hydrocarbon mixtures in blood using gas chromatography/mass spectrometry with a wide-bore capillary column

A screening method for detecting volatile hydrocarbons in blood has been developed using gas chromatography/mass spectrometry with a wide-bore capillary column and a headspace method. Toluene-d8 and indan were used as the internal standards for quantitative analysis. Hydrocarbons with retention indices from 600 to 1200 were simultaneously and quantitatively detected in relatively low concentrations (0.01 microgram/ml) in reconstructed ion chromatography. This method could prove useful in forensic cases in which urgent examination of complex hydrocarbon mixtures, e.g. petroleum components, is required.     

An adsorption sampling method combined with capillary column gas chromatography and cryogenic focussing for trace analysis of volatile organic compounds

A simple, inexpensive and versatile gas chromatography modification is presented, that allows sensitive and reproducible analysis of organic volatiles at the trace level by a combination of static headspace sampling (using Porapak Q resin), thermal desorption (using a commercial pyrolyser) and simple cryogenic focussed glc.     

Methamphetamine impurity profiling using a 0.32 mm i.d. nonpolar capillary column

Classification of seized methamphetamine by impurity profiling can provide very useful information in criminal investigations of drug traffic routes, sources of supply and relationships between seizures. The aim of this study is to improve and develop an analytical method for detecting impurities such as starting materials and by-products in illegally prepared methamphetamine.HCl samples. A 50mg sample of methamphetamine.HCl was dissolved in 1 ml of buffer solution (four parts 0.1M phosphate buffer pH 7.0 and one part 10% Na2CO3). Impurities were extracted with 0.5 ml of ethyl acetate containing four internal standards (ISs) (n-decane, n-pentadecane, n-nonadecane and n-hexacosane) and analyzed by gas chromatography (GC) using a flame ionization detector (FID) on a DB-5 capillary column (0.32 mmi.d. x 30 m, film thickness 1.0 microm). The use of a middle-bore column offered better separation of the impurity peaks. The correction of the retention times of impurity peaks with four ISs made peak identification very accurate for subsequent data processing. Twenty-four characteristic peaks were selected for comparison and similarity and/or dissimilarity between samples, and the data were evaluated by the Euclidean distance of the relative peak areas after logarithmic transformation. The results indicate that the present method would be useful for methamphetamine impurity profiling.     

氟乙酰胺和氟乙酸的毛细管柱气相色谱检测

本文建立氟乙酰胺和氟乙酸的毛细管柱气相色谱检测方法，氟乙酰胺和氟乙酸的线性检测范围为0．0625mg/ml～4mg／ml和0．625mg／ml~20mg／ml，最小检出浓度为31．25ug／ml和625ng/ml．太原地区地摊所售鼠药87．5％含有氟乙酰胺，30％含有氟乙酸．     

The analysis of clingfilms by infrared spectroscopy and thermal desorption capillary gas chromatography.

An automated thermal desorption gas chromatography technique has been adapted to analyse traces of volatile compounds in proprietary food-wrapping films. Fourteen brands of polyvinylchloride film, seven brands of polyethylene film and one polyvinylidene chloride film were discriminated. Prior infrared analysis was used to identify the polymer type. The chromatograms showed minor changes in volatiles along the length of a roll of film and major changes in films exposed to daylight or in contact with cannabis resin.     

毛细管气相色谱法测定酱油中4-甲基咪唑的含量

目的建立毛细管气相色谱法定量分析酱油中有毒成分4-甲基咪唑的方法。方法酱油样品在层析柱中用二氯甲烷洗脱,洗脱液浓缩后加入N,N-二甲基苯胺作为内标,采用DB-FFAP毛细管柱分离样品,氮磷检测器测定4-甲基咪唑含量。结果方法线性范围为4.9~1.5×102μg/L;检测限为0.16μg/L;标准加入0.0102mg和0.0602mg 4-甲基咪唑的平均回收率为97.25%和99.44%。结论本文方法具有操作简便、快速、准确等优点,可用于检验酱油中的4-甲基咪唑。     

Rapid extraction and capillary gas chromatography for diazine herbicides in human body fluids

A simple and rapid method for the extraction of four diazine herbicides (terbacil, bromacil, norflurazon and PAC) from human whole blood, plasma and urine with use of Bond Elut C₁₈ cartridges is presented. Whole blood, plasma and urine samples containing the herbicides, after mixing with distilled water, were loaded on Bond Elut C₁₈ cartridges and the herbicides were eluted with chloroform/methanol (9:1). They were detected by capillary gas chromatography with flame ionization detection (FID) with splitless injection. Separation of the four diazine herbicides from each other and from impurities was generally satisfactory with the use of an intermediately polar DB-17 capillary column. The recovery of all compounds, which had been added to whole blood, plasma and urine, was > 89%. The calibration curve for the herbicides, which has been added to whole blood, plasma and urine, showed linearity in the range 1.6–100 ng on column. Their detection limits were 1.2–1.4 ng on column for whole blood and plasma, and 1.1–1.2 ng on column for urine.     

Packed column chromatography, high-resolution gas-chromatography and high pressure liquid chromatography in comparison for the analysis of cannabis constituents

The identification and the quantitative estimation of cannabis constituents is important for forensic purposes. High resolution gas-chromatography gives better results than gas-liquid chromatography with packed columns, as it shows a better resolution and higher number of constituents. Different quantitative values were found with the two chromatographic procedures. High-pressure liquid chromatography revealed the presence of cannabinoid acids in fresh cut influorescences of cannabis plants. The ratio acid/neutral cannabinoid may be useful in supplying information about the age of the cannabis preparations.     

Automated headspace solid-phase microextraction and capillary gas chromatography analysis of ethanol in postmortem specimens

Solid-phase microextraction (SPME) is a relatively new solventless sample preparation technique that allows simultaneous sampling, extraction, pre-concentration, and introduction of analytes from a sample matrix in a single procedure. This methodology has been used for the analysis of several drugs of forensic toxicology interest including volatile compounds. This paper describes a methodology for analysis of ethanol and other volatile compounds using automatic headspace solid-phase microextraction (HS-SPME) and capillary gas chromatography in postmortem specimens. The methodology was initially developed using standard solutions of acetaldehyde, acetone, methanol, and ethanol. Isobutanol was used as internal standard. Postmortem samples of blood, urine, and vitreous humor were obtained during medico-legal autopsies. To date, there are no published paper regarding alcohol analysis in vitreous humor specimens using HS-SPME and limited literature analyzing blood and urine samples. HS-SPME analysis showed that, under optimized conditions, ethanol and isobutanol (internal standard) were well-separated from other volatile compounds such as acetaldehyde, acetone, and methanol considered to be potential interferents in ethanol analysis. The calibration curves for each volatile compound demonstrated good linearity throughout the concentration range from 0.001 to 1.0 g/dl and the detection limit of ethanol in the studied specimens was approximately 0.0001 g/dl.     

Rapid isolation with Sep-Pak C18 cartridges and capillary gas chromatography of triazine herbicides in human body fluids.

A simple and rapid method, for the isolation of eight triazine herbicides from human serum and urine, using Sep-Pak C18 cartridges is presented. After mixing with distilled water, serum and urine samples containing the herbicides, were loaded on Sep-Pak C18 cartridges and eluted with either chloroform only or chloroform/methanol (9:1). The herbicides were detected by capillary gas chromatography with both flame ionization detection (FID) and nitrogen-phosphorus detection (NPD). Separation of eight triazine herbicides from each other and from impurities was generally satisfactory with the use of a non-polar DB-1 capillary column. Recovery of most compounds was excellent for both chloroform and chloroform/methanol (9:1) as elution solvents. Backgrounds were cleaner and evaporation time was shorter for the chloroform only than for the chloroform/methanol (9:1). The NPD gave sensitivity more than 10-20 times higher than that of FID.     

Rapid isolation with Sep-Pak C18 cartridges and wide-bore capillary gas chromatography of some butyrophenones

A simple and rapid method for isolation of five butyrophenones with Sep-Pak C18 cartridges from human samples, and their wide-bore capillary gas chromatography (GC), are presented. The GC was made by both flame ionization and electron capture detections. The drugs contained in alkaline samples were directly applied to the cartridges and eluted with chloroform/isopropanol (9:1). The recoveries with use of the cartridges were excellent for most drugs in both urine and plasma samples. We can recommend the Sep-Pak C18 cartridges for isolation of butyrophenones because of simplicity and rapidity, and also wide-bore capillary GC because of high sensitivity and low decomposition of drugs during passage through the column.     

Rapid isolation with Sep-Pak C18 cartridges and wide-bore capillary gas chromatography of organophosphate pesticides

A simple and rapid method for isolation of eleven organophosphate pesticides with Sep-Pak C18 cartridges from human urine and plasma, is presented. The detection of the pesticides was made by wide-bore capillary gas chromatography (GC) with flame ionization detection. The pesticide-containing samples, after mixing with water, were directly applied to the cartridges and eluted with chloroform/isopropanol (9:1). The recoveries with use of the cartridges were excellent for most pesticides. Separation of each pesticide peak from each other and from impurities on the gas chromatograms was also satisfactory with use of non-polar and slightly polar capillary columns. The isolation method with use of the cartridges, together with the wide-bore capillary GC, seems very useful in forensic and environmental chemistry and clinical toxicology.     

Comparison and classification of methamphetamine seized in Japan and Thailand using gas chromatography with liquid-liquid extraction and solid-phase microextraction

Methamphetamine (MA) is one of the most frequently abused drugs worldwide. The aim of this study is to improve the analytical method for profiling MA impurity in order to compare and classify MA crystals seized in different countries and to investigate the relationships between seizures. To compare MA samples seized in Japan and Thailand, the following analytical method was adopted. A 50mg sample of MA.HCl was dissolved in 1ml of buffer solution (four parts 0.1M phosphate buffer, pH 7.0, and one part 10% Na(2)CO(3)), impurities were extracted with 0.5ml of ethyl acetate containing four internal standards (n-decane, n-pentadecane, n-eicosane and n-octacosane) and analyzed by gas chromatography with a flame ionization detector on a DB-5 capillary column (0.32mm i.d.x30m, film thickness 1.0mum). Fourteen characteristic peaks on chromatograms were selected for the comparison and classification of samples, and the data were evaluated by the Euclidean distance of the relative peak areas after logarithmic transformation. Sixty-nine samples seized in Japan and 42 seized in Thailand were analyzed. The samples were classified into four groups roughly by cluster analysis. In addition, when it was difficult to compare samples that had fewer impurities on chromatograms obtained from liquid-liquid extraction (LLE), solid-phase microextraction (SPME) was effective. Because many characteristic peaks were detected using SPME, SPME made it easy to compare samples of high purity. The combination of LLE and SPME was useful for impurity profiling of MA samples seized in different countries.