Use of short, wide-bore capillary columns in GC toxicological screening.

The usefulness of wide-bore, thick film capillary columns for routine toxicological screening was assessed. Two such columns were examined: fused silica CPSil 5CB (i.d., 0.53 mm; length, 10 m; film thickness, 5.2 microns) and glass SPB-1 (i.d. 0.75 mm; length, 30 m; film thickness, 1.0 micron). A standard packed column filled with 3% OV-1 (i.d., 2 mm; length, 1.5 m) and a medium-bore fused silica column CPSil 5 (i.d., 0.32 mm; length, 25 m; film thickness, 0.4 micron) were examined for comparison. Mixtures of alkanes and drugs, as well as biological samples from routine casework, were analyzed. Both types of wide-bore columns proved to be very useful in routine toxicological practice, due to satisfactory efficiency, high capacity, and ease of installation. The retention index values of various drugs, examined on wide-bore columns, were in agreement with the reference database obtained from packed columns.

Rapid determination of ethylene glycol in biological material.

A rapid and simple modification of a gas chromatographic (AFID) method of ethylene glycol determination, based on derivation with n-butylboronic acid, was developed.

Impact of biological matrix, drug concentration, and method of isolation on detectability and variability of retention index values in gas chromatography.

The retention indices of eight basic and neutral drugs extracted from plasma, blood, or liver homogenate by six different methods were calculated using temperature-programmed gas chromatography on OV-1 and SE-30 columns. Two concentrations were applied: 1 and 50 mg/L, respectively. The type of extraction had great influence on recovery and analytical background. The retention indices tended to be slightly concentration-dependent in that they were somewhat lower at higher drug concentration. Neither the biological sample nor the type of extraction exerted significant influence on scatter and mean value of the retention indices.

Enzymic hydrolysis of tissues before XAD-2 extraction in poisoning cases.

Samples of blood, liver and brain taken from 13 cases of fatal poisoning with barbiturates, antidepressants, phenothiazines and anticonvulsants were digested with trypsin and beta-glucuronidase. The concentrations of drugs were higher in hydrolyzed livers in barbiturate and phenothiazine poisonings. In the case of diazepam, phenytoin, carbamazepine, amitriptyline, imipramine and chloroprothixene poisonings the results obtained after enzymic hydrolysis were the same or worse than in controls. The blood levels of drugs in non-fatal poisonings with diazepam, doxepin and chlorpromazine were similar in samples digested with trypsin and in controls. All samples were extracted with Amberlite XAD-2 resin by XAD-2 Bag technique.

Enzymic digestion of biosamples as a method of sample pretreatment before XAD-2 extraction.

Four proteolytic enzymes trypsin, protease type I, protease type V (Pronase AS) and protease type VIII (Subtilisin) were used for digestion of blood, brain, liver, and kidney in experimental poisonings of dogs with phenobarbital, amitriptyline, diazepam, and chlorpromazine. Enzymic digestion was used also in 21 forensic cases of fatal poisonings with hypnotic and psychotropic drugs. Each enzyme applied gave a similar yield. The efficienct of enzymic digestion varied according to the kind of drug, tissue, and individual. In general, enzymic hydrolysis proved useful in isolation of psychotropic drugs from liver and brain, being less effective in the case of blood. The mechanism of drugs liberation after enzymic treatment remains obscure.

Blood cyanide and thiocyanate concentrations after administration of sodium nitroprusside as hypotensive agent in neurosurgery.

In a group of 50 neurosurgical patients receiving sodium nitroprusside as a hypotensive agent, in doses of 50--2131 microgram/kg body weight, whole blood cyanide was estimated before infusion of drug, during infusion, immediately after infusion, and 1 and 3 h later. Cyanide values increased significantly, reaching the maximum in a sample taken immediately after infusion (mean value, 333; highest value, 1800 microgram/liter). Values correlated closely with both dose and rate of infusion. Blood thiocyanate, estimated before, immediately after, and 3 h after the infusion, showed no significant changes in thiocyanate concentration. In any case, no signs or symptoms of cyanide or thiocyanate poisoning were observed. We conclude that sodium nitroprusside, in the proper dose and given at the proper rate, does not precipitate cyanide poisoning.

Isolation of drugs from autopsy material by XAD-2 adsorption-elution technique. A routine procedure.

The method of adsorption of drugs on Amberlite XAD-2 resin, followed by differential elution was under study during 1 1/2 year of routine use. The method allows a separation of acidic and basic drugs and--due to acid hydrolysis step before adsorption--assures better recovery of conjugated and protein-bound drugs. The amounts of various drugs, found in autopsy cases by the XAD-2 method were usually higher than those found by solvent extraction. The method applied requires 20 g of sample (biofluid or tissue) for general toxicological analysis.

Isolation of drugs from blood and tissues with XAD-2 bags.

Nylon bags containing 2-g portions of Amberlite XAD-2 resin were used for systematic analysis of drugs in biosamples. The procedure requires 10 or less grams of material, two XAD-2 bags, and enables rapid and economical isolation of most common drugs. The method was demonstrated on autopsy blood spiked withe 19 of the most common drugs, and was routinely used in cases of fatal and non-fatal poisoning. The eluates were clean and suitable for direct gas chromatographic and ultraviolet spectrophotometric analysis. The procedure used appeared more convenient than XAD-2 column extraction procedures. Classic solvent extraction methods were usually less efficient.