Detection and identification of volatile organic compounds in blood by headspace gas chromatography as an aid to the diagnosis of solvent abuse

Development and Validation of a Headspace GC-MS Method for Simultaneous Quantification of Antimicrobial Preservatives in Biopharmaceutical Peptide Formulations

The four most used antimicrobial preservatives in biopharmaceutical parenteral formulations are phenol, meta-cresol, chlorobutanol, and benzyl alcohol. Preservatives are included in various combinations in biopharmaceuticals highlighting the importance of an analytical method to quantify the four preservatives simultaneously. A headspace GC-MS method was developed to quantify phenol, chlorobutanol, meta-cresol, and benzyl alcohol. The method was validated according to USP <1225>. System suitability was conducted daily for retention time (%RSD < 2.0%), peak area (%RSD < 5.0%), USP tailing factor (< 2.0 and %RSD < 10.0%), and peak resolution (> 2.0). Analytical ranges were 1.5-90 μg/mL for phenol and meta-cresol, 30-240 μg/mL for benzyl alcohol, and 30-300 μg/mL for chlorobutanol. Method accuracy ranged from 94% to 108% and precision from 4% to 15 %RSD for all the tested preservatives. The method was applied to three marketed teriparatide drug products selected as a model. Preservative concentrations of the biopharmaceutical marketed products were determined and were found to be comparable with the labeled concentrations, except for an expired product with 2.5% of the label claim. The developed headspace GC-MS method can be used to evaluate the drug quality of the parenteral formulations and to support the assessment of biopharmaceutical peptide drug products.

Profiling of cured residue of solvent-based adhesives by attenuated total reflectance-Fourier transform infrared spectroscopy with chemometrics for forensic investigation

Abuse of solvent-based adhesives jeopardizes world population, especially the young generation. Adhesive-related exhibits encountered in forensic cases might need to be determined if they could have come from a particular source or to establish link between cases or persons. This study was aimed to discriminate solvent-based adhesives, especially to aid forensic investigation of glue sniffing activities. In this study, thirteen brands with three samples each, totaling at 39 adhesive samples, were analyzed using attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy followed by chemometric methods. Experimental output showed that adhesive samples utilized in this study were less likely to change in their ATR-FTIR profiles over time, at least up to 2 months. No interference from plastic materials was noticed based on ATR-FTIR profile comparison. Physical examination could differentiate the samples into two groups, namely contact adhesives and cement adhesives. A principal component analysis-score linear discriminative analysis (PC-score LDA) model resulted in 100% and 98.6% correct classification in discriminating the two groups of adhesive samples, forming seven discriminative clusters. Test set with adhesive samples applied glass slide and plastic substrates also demonstrated a 100% correct classification into their respective groups. As a conclusion, the method allowed for discrimination of adhesive samples based on the spectral features, displaying relationship among samples. It is hoped that this comparative information is beneficial to trace the possible source of solvent-based adhesives, whenever they are recovered from a crime scene, for forensic investigation.

Impact of UV-C treatment and thermal pasteurization of grape must on sensory characteristics and volatiles of must and resulting wines

UV-C treatment is a commonly known technique to inactivate microorganisms. The objective of this work was to investigate the impact of UV-C treatment of grape must on the sensory characteristics of the resulting wine and on the profile of volatile compounds of grape must and wine. Different UV-C doses were applied to Riesling must and compared with thermal pasteurization. The sensory off-flavor "ATA" and a content of 0.5 µg/L 2-aminoacetophenone were determined in the grape must and in the resulting wine after UV-C treatment with a high dose of 21 kJ/L. Sensory off-flavors did neither occur after thermal pasteurization nor after UV-C treatment with a dose of 2 kJ/L, which is sufficient for the inactivation of microorganisms. Minor changes in the volatiles' profiles of grape must and wine, involving e.g. terpenes and C13-norisoprenoids, occurred in musts treated with thermal pasteurization as well as with a UV-C dose of 2 kJ/L.

Obstructive sleep apnea patients can be identified by ion mobility spectrometry-derived smell prints of different biological materials

BACKGROUND

The analysis of obstructive sleep apnoea syndrome (OSAS) is time- and cost-intensive. A number of studies demonstrated that the non-invasive analysis of exhaled breath (EB) may be suitable to distinguish between OSAS patients and healthy subjects (HS). Methods/Population: We included OSAS patients (n = 15) and HS (n = 15) in this diagnostic proof-of-concept-study. All participants underwent polygraphy to verify or exclude OSAS and performed spirometry to exclude pulmonary ventilatory diseases. The volatile organic compound profile of EB and of the headspaces over EB condensate, pharyngeal washing fluid, and serum was measured using ion mobility spectrometry (IMS) (BioScout^®) and an e-nose (Cyranose^® 320). For the statistical analysis, we fitted classification tree models using recursive partitioning, followed by a leave-one-out cross-validation. For the cross-validated predictions we calculated descriptive classification statistics, p-values from a [Formula: see text]-test with continuity correction, as well as ROC curves.

RESULTS

Using IMS, OSAS patients and HS could be distinguished with high accuracy (values ranged from 79% to 97%). The results of the e-nose-derived analyses (with the exception of EB) were less accurate. However, the cross-validated accuracy for EB was very good (0.9), reflecting a positive predictive value of 100% and a negative predictive value of 83%. For each material, we identified the best five substances that may be used for diagnostic purposes. 2-Methylfluran was found in three different biological materials to be discriminative between OSAS and HS.

CONCLUSION

The results strengthen the hypothesis that substances detectable in headspace measurements of different airway and blood materials may undergo a transition from blood into the alveoli (and EB) or vice versa. This means that substances from different compartments could be used to distinguish patients with airway diseases (in this case OSAS) from healthy controls.

Volatile Hydrocarbon Analysis in Blood by Headspace Solid-Phase Microextraction: The Interpretation of VHC Patterns in Fire-Related Incidents

A headspace solid-phase microextraction (HS-SPME) technique was used to quantitate the concentration of volatile hydrocarbons from the blood of cadavers by cryogenic gas chromatography-mass spectroscopy. A total of 24 compounds including aromatic and aliphatic volatile hydrocarbons were analyzed by this method. The analytes in the headspace of 0.1 g of blood mixed with 1.0 mL of distilled water plus 1 µL of an internal standard solution were adsorbed onto a 100-µm polydimethylsiloxane fiber at 0°C for 15 min, and measured using a GC-MS full scan method. The limit of quantitation for the analytes ranged from 6.8 to 10 ng per 1 g of blood. This method was applied to actual autopsy cases to quantitate the level of volatile hydrocarbons (VHCs) in the blood of cadavers who died in fire-related incidents. The patterns of the VHCs revealed the presence or absence of accelerants. Petroleum-based fuels such as gasoline and kerosene were differentiated. The detection of C8-C13 aliphatic hydrocarbons indicated the presence of kerosene; the detection of C3 alkylbenzenes in the absence of C8-C13 aliphatic hydrocarbons was indicative of gasoline; and elevated levels of styrene or benzene in the absence of C3/C4 alkylbenzenes and aliphatic hydrocarbons indicated a normal construction fire. This sensitive HS-SPME method could help aid the investigation of fire-related deaths by providing a simple pattern to use for the interpretation of VHCs in human blood.

5 Final Report on the Safety Assessment of Ethyl Acetate and Butyl Acetate

Ethyl and Butyl Acetate are used as solvents in nail polish, nail polish removers, basecoats, and other manicuring preparations.

Ethyl and Butyl Acetate were relatively nontoxic when administered orally, dermally, or by inhalation to rabbits, rats, mice, and guinea pigs. A nail polish containing 10% Ethyl Acetate and 25% Butyl Acetate was a moderate to severe irritant in unrinsed rabbit eyes and a mild irritant in rinsed rabbit eyes. Butyl Acetate was not a sensitizer in either mice or guinea pigs.

Ethyl and Butyl Acetate were nonmutagenic when tested by the Ames procedure, Rec-assay, and micronucleus assay. Neither compound induces mitotic aneuploidy in yeast or chromosomal aberrations in Chinese hamster fibroblasts. Butyl Acetate was not teratogenic when inhaled.

Ethyl Acetate and Butyl Acetate were mild skin irritants but not sensitizers to humans. Ethyl Acetate was neither phototoxic or photoallergenic in human tests.

It is concluded that Ethyl Acetate and Butyl Acetate are safe as cosmetic ingredients in the present practices of use and concentration.

Assessment of carboxyhemoglobin, hydrogen cyanide and methemoglobin in fire victims: a novel approach

To establish the cause of death, carboxyhemoglobin (COHb), total hemoglobin (tHb), methemoglobin (MetHb), and hydrogen cyanide (HCN) were quantified in the blood of fire victims. We analyzed 32 out of 33 blood samples from forensic autopsy cases in a disastrous polyurethane mattress fire, which caused the deaths of 33 inmates at a prison in Argentina in 2006. The cadaveric blood samples were collected by femoral vein puncture. These samples were analyzed using the IL80 CO-oximeter system for tHb, MetHb, and COHb levels and by microdiffusion for HCN and COHb levels. Blood alcohol (ethanol) and drugs were examined by headspace gas chromatography-flame ionization detection (HS-GC-FID) and GC-mass spectrometry (MS), respectively. Polyurethane mattress samples were analyzed according to the California 117 protocol. The saturation of COHb ranged from 10% to 43%, tHb from 2% to 19.7%, MetHb from 0.10% to 35.7%, and HCN from 0.24 to 15mg/L. These HCN values are higher than the lethal levels reported in the literature. Other toxic components routinely measured (ethanol, methanol, aldehydes, and other volatile compounds) gave negative results in the 32 cases. Neither drugs of abuse nor psychotropic drugs were detected. The results indicate that death in the 32 fire victims was probably caused in part by HCN, generated during the extensive polyurethane decomposition stimulated by a rapid increase in temperature. We also considered the influence of oxygen depletion and the formation of other volatile compounds such as NOx in this disaster, as well as pathological evidence demonstrating that heat was not the cause of death in all victims. Furthermore, statistical analysis showed that the percentage values of COHb and MetHb in the blood were not independent variables, with χ(2)=11.12 (theoretical χ(2)=4.09, degrees of freedom=12, and α=0.05). However, no correlation was found between HCN and MetHb in the blood of the victims. This is the first report to assess the relationship between COHb and MetHb in forensic blood samples. We further discuss other factors that could lead to a lethal atmosphere generated by the fire and compare the data from this disaster with that of other published fire episodes.

An improved approach for accurate quantitation of benzene, toluene, ethylbenzene, xylene, and styrene in blood

Widespread exposure to benzene, toluene, ethylbenzene, xylene, and styrene (BTEXS) and the potential for this exposure to cause health effects drives the need to develop improved methods for measuring exposure. In this work, we demonstrate our latest assay for quantifying BTEXS in blood and characterize sources of both positive and negative biases. This method involves blood sample collection using common techniques followed by static headspace sampling using solid-phase microextraction and gas chromatography/mass spectrometry analysis. We found that the greatest and unexpected source of positive bias was from contamination of butyl rubber materials used in sample preparation consumables such as Vacutainer stoppers, syringe plungers, and sample vial septa. Conversely, the primary cause of negative bias observed was from the diffusion loss of BTEXS from blood during transfer into sample vials. By minimizing or eliminating these and other sources of bias, we improved method accuracy and precision to within 10% while maintaining low-picogram per milliliter detection. Furthermore, upon comparison of these results with those from other laboratories, we observe substantially lower blood BTEXS levels reported to date for nonoccupationally exposed nonsmokers. A relatively unbiased method, as such, will help elucidate any potential associations between adverse health effects and human exposure to low levels of BTEXS.

A review of analytical methods for the identification and quantification of hydrocarbons found in jet propellant 8 and related petroleum based fuels

Jet propellant 8 (JP-8) is a complex mixture of compounds that varies from batch to batch. Quantification of various compound classes of JP-8, including BTEX, PAHs and VOCs, has been accomplished. Very few papers have tackled total JP-8 quantification because of its complexity. The components in JP-8 tend to co-elute and present at low concentrations, often nondetectable. JP-8 is the major source of chemical exposure for Department of Defense personnel and a potential hazard for civilians and marine animals. Some components of JP-8 have been identified as possible human carcinogens and have been studied extensively. Development of analytical methods to analyze the components of this fuel are essential to measure the extent of exposure, as well as the short-term and long-term exposure in rodents, humans and marine life. To date, JP-8 has been examined in urine, blood, contaminated water and fish tissue. This paper reviews methods currently utilized in the literature for the analysis of JP-8 and its components. This paper also discusses extraction methods and detectors commonly used in JP-8 and hydrocarbon analysis in general. Finally, the effects of exposure and the future of JP-8 and petroleum analysis with respect to human health are discussed.

High operationally stable sol-gel diglycidyloxycalix[4]arene fiber for solid-phase microextraction of propranolol in human urine

A simple, sensitive, and accurate method for the determination of propranolol in human urine has been developed based on solid-phase microextraction (SPME) followed by GC-flame ionization detection (FID). The sol-gel 5,11,17,23-tetra-tert-butyl-25,27-dihydroxy-26,28-diglycidyloxycalix[4]arene/hydroxy-terminated silicone oil (diglycidyloxy-C[4]/OH-TSO) fiber was prepared to accommodate to the harsh extraction conditions. It possesses excellent alkali-proof ability and retains its extraction characteristics intact even after treatment with highly alkaline (4 mol/L) NaOH solution. Direct chemical bonding of the coating to the fiber surface provides it with excellent solvent resistance and the introduction of calixarene enhances its thermal stability. The newly developed sol-gel calixarene coating was effectively used for the extraction of propranolol in human urine. No interference with the determination of propranolol was observed from the urine components. Standard curves were linear in the range 50-5000 microg/L for headspace-SPME (HS-SPME) and 25-25000 microg/L for direct-SPME (Dir-SPME) with correlation coefficients better than 0.9999. The detection limit was 0.275 microg/L for HS-SPME and 0.193 microg/L for Dir-SPME. The method was validated using standard addition methodology and recovery values were between 91.4 and 117% for both the sampling modes with the RSDs less than 6% at different concentration levels in the linear ranges. The results obtained by both the sampling modes were feasible, and no significant differences between them regarding accuracy, precision, and detection limits were seen.

Analytical method for evaluation of exposure to benzene, toluene, xylene in blood by gas chromatography preceded by solid phase microextraction

Frequency of intentional exposure to organic solvents has been increasing among children and adolescents in Brazil. Analysis of benzene, toluene and xylenes (BTX) in human blood is necessary to diagnose the intentional and accidental exposure to these solvents. A method for BTX determination in blood samples by gas chromatography preceded by solid phase microextration (SPME) from headspace (HS) has been described. SPME has several advantages when compared to other extraction techniques such as simplicity, low cost and solvent-free extraction. The method presents good repeatability (precision was of 2.2-8.0%), accuracy from -4.7 to -9.4%, limit of detection <1.0 ug/mL, linearity from 1.0 to 100 ug/mL for toluene and from 5.0 to 100 ug/mL for the other solvents (R2 > 0.99), which shows to be efficient and adequate for the detection of exposure to BTX in blood samples.

Optimized determination of trace jet fuel volatile organic compounds in human blood using in-field liquid-liquid extraction with subsequent laboratory gas chromatographic-mass spectrometric analysis and on-column large-volume injection

A practical and sensitive method to assess volatile organic compounds (VOCs) from JP-8 jet fuel in human whole blood was developed by modifying previously established liquid-liquid extraction procedures, optimizing extraction times, solvent volume, specific sample processing techniques, and a new on-column large-volume injection method for GC-MS analysis. With the optimized methods, the extraction efficiency was improved by 4.3 to 20.1 times and the detection sensitivity increased up to 660 times over the standard method. Typical detection limits in the parts-per-trillion (ppt) level range were achieved for all monitored JP-8 constituents; this is sufficient for assessing human fuels exposures at trace environmental levels as well as occupational exposure levels. The sample extractions are performed in the field and only solvent extracts need to be shipped to the laboratory. The method is implemented with standard biological laboratory equipment and a modest bench-top GC-MS system.

Headspace gas chromatography-mass spectrometry analysis of isoflurane enantiomers in blood samples after anesthesia with the racemic mixture

Several in vivo and in vitro studies on the stereoselective potency of isoflurane enantiomers suggest beneficial effects of the (+)-(S)-enantiomer. In order to detect possible differences in the pharmacokinetics of isoflurane enantiomers, a clinical study of 41 patients undergoing general anesthesia maintained with racemic isoflurane was performed. The isoflurane enantiomers were analyzed in blood samples drawn before induction, at cessation (day 0), and up to eight days after isoflurane anesthesia (day 1-8). A multipurpose sampler (Gerstel MPS) was used for the headspace gas chromatography-mass spectrometry (GC/MS) analysis, and it was combined with a cold injection system (Gerstel CIS 3) for coldtrapping, enrichment, and focusing of the analyte. The enantiomer separation was achieved by using a capillary column coated with octakis(3-O-butanoyl-2,6-di-O-pentyl)-gamma-cyclodextrin (Lipodex E) dissolved in the polysiloxane PS 255. Detection was done in the selected ion monitoring mode with ions m/z 117 and m/z 149. An enrichment of (+)-(S)-isoflurane in all blood samples drawn after anesthesia was found. The highest enantiomer bias, up to 52-54% (+)-(S)-isoflurane as compared to 50% for the racemate, was observed on day 2 for most of the patients. Furthermore, quantification of isoflurane in blood samples of five patients was done by enantiomer labeling, employing enantiomerically pure (+)-(S)-isoflurane as internal standard. The isoflurane concentration decreased rapidly from 383 nmol/ml to 0.6 nmol/ml (mean values) eight days after anesthesia. The present study shows differences in the pharmacokinetics of isoflurane enantiomers in man. However, it is not possible to distinguish between enantioselective distribution and enantioselective metabolism, if any.

Method for liquid-liquid extraction of blood surrogates for assessing human exposure to jet fuel

A baseline method of liquid-liquid extraction for assessing human exposure to JP-8 jet fuel was established by extracting several representative compounds ranging from very volatile to semi-volatile organic compounds, including benzene, toluene, nonane, decane, undecane, tridecane, tetradecane and pentadecane, from PBS buffer. Some specific techniques for solvent selection, solvent evaporation, and GC analysis were developed to accommodate this wide range of constituents of JP-8. The application of the established method to the extraction and quantitative analysis of JP-8 from PBS and bovine plasma was demonstrated.

Headspace gas chromatography with capillary column for urine alcohol determination

A headspace gas chromatographic method using a fused-silica capillary column Poraplot Q has been developed and validated for the detection and quantification of ethanol in urine. Under optimized conditions, ethanol was properly separated from acetaldehyde, acetone, isopropanol, methanol and n-propanol. Limits of detection (LODs) and quantification (LOQs) were 0.008 and 0.010 g/l, respectively. The precision studies within-run and between-run, using spiked urine samples (0.08, 0.8 and 2.0 g/l) showed maximum coefficients of variation 5.9 and 6.5%, respectively. Results of ethanol recovery varied from 91.6+/-0.8 to 103.3+/-1.8% over the concentration range from 0.01 to 3.20 g/l. The method was appropriate for the detection of ethanol in urine samples. This matrix can be used for monitoring alcohol abuse in the workplace and used in alcohol rehabilitation programs.

Determination of the chlorofluorocarbon substitute 1,1,1,2-tetrafluoroethane (HFA-134a) in human and animal blood using gas chromatography with headspace analysis

A gas chromatographic procedure with headspace analysis and flame-ionization detection is described for the determination of the chlorofluorocarbon substitute 1,1,1,2-tetrafluoroethane (HFA-134a). A 0.5-2 ml sample of heparinized whole blood from a laboratory animal or human is added directly into a presealed headspace vial from which an equivalent volume of air has been removed. The internal standard 1,1,2,2-tetrafluoroethane is added and the sample frozen until analysis. Chromatographic separation is achieved using a PoraPlot Q porous-layer capillary column. The analytical range is 5.8-3298 ng/ml when 2-ml human blood samples are used. The concentration range of the calibration curve can be easily adapted to accommodate the concentrations expected in either pharmacokinetic or toxicokinetic studies. Automation of the assay permits the maximum number of samples to be processed in a day.

Saliva testing for drugs of abuse

Saliva testing for drugs of abuse can provide both qualitative and quantitative information on the drug status of an individual undergoing testing. Self-administration by the oral, intranasal, and smoking routes often produces "shallow depots" of drug that contaminate the oral cavity. This depot produces elevated drug concentrations that can be detected for several hours. Thereafter, saliva drug concentrations generally reflect the free fraction of drug in blood. Also, many drugs are weak bases and saliva concentrations may be highly dependent upon pH conditions. These factors lead to highly variable S/P ratios for many of the drugs of abuse. Table 3 provides a compilation of experimental and theoretical S/P (total) ratios determined for drugs of abuse. Estimations of the theoretical S/P (total) ratios for acidic and basic drugs were based on the Henderson-Hasselbalch equation. Saliva pH was assumed to be 6.8 unless reported otherwise by the investigators. Generally, there was a high correlation of saliva drug concentrations with plasma, especially when oral contamination was eliminated. Assay methodology varied considerably, indicating that saliva assays could be readily developed from existing methodology. There are many potential applications for saliva testing for drugs of abuse. Table 4 lists several general areas in which information from saliva testing would be useful. Clearly, saliva drug tests can reveal the presence of a pharmacologically active drug in an individual at the time of testing. Significant correlations have been found between saliva concentrations of drugs of abuse and behavioral and physiological effects. Results indicate that saliva testing can provide valuable information in diagnostics, treatment, and forensic investigations of individuals suspected of drug abuse. It is expected that saliva testing for drugs of abuse will develop over the next decade into a mature science with substantial new applications.

Chromatographic determination of volatile solvents and their metabolites in urine for monitoring occupational exposure

The determination of volatile solvents and their metabolites in biological materials such as expired air, blood or urine allows the estimation of the degree of exposure of these chemicals. Chromatographic methods are now universally employed for this purpose and numerous analytical procedures are available for the determination of the most commonly used volatile solvents and their metabolites in urine. GC methods appear well adapted to the determination of the parent volatile solvents in blood and urine and may be used for the determination of their urinary metabolites, but these methods often require several prechromatographic steps. However, HPLC is becoming a powerful tool for the accurate and easy determination of urinary metabolites of volatile solvents, considering its decisive advantages for routine monitoring. Further, recent developments in HPLC could widen the usefulness of this method for most complex analytical problems that could be encountered during this measurement. However, despite the relative neglect of planar chromatography in this area of concern and considering the great interest in methods that could permit the simultaneous assay of numerous samples often required by routine monitoring, new approach using improved methods such as overpressured TLC could be very fruitful in the future.

Biological exposure indices of organic solvents for Korean workers

Biological exposure indices (BEIs) of toluene, perchloroethylene (PCE) and methyl ethyl ketone (MEK) for Korean workers were studied respectively. Exposure in workplace to organic solvents were measured by personal sampling. Blood toluene, blood PCE, urinary trichloroacetic acid and urinary MEK were determined by headspace GC. Urinary hippuric acid was determined by HPLC and corrected for creatinine. BEIs for Korean workers were calculated with the levels of the determinants corresponding to permissible exposure limits in Korea which were the same with TLV of ACGIH. Blood toluene level of 2.2 mg/l and urinary hippuric acid level of 1.7 g/g creatinine corresponded to exposure of 100 ppm toluene. Blood PCE concentration of 1.6 mg/l and urinary trichloroacetic acid concentration of 2.9 mg/l corresponded to exposure to 50 ppm PCE. Urinary MEK concentration of 1.4 mg/l corresponded to exposure to 200 ppm of MEK. In conclusion, BEIs for Korean workers determined in this study were different to ACGIH's BEI as urinary determinants were lower and blood determinants were higher than ACGIH's BEI.

Environmental and biological monitoring of methyl ethyl ketone (MEK)

This study was conducted to evaluate the usefulness of various biological parameters for monitoring of workers exposed to methyl ethyl ketone (MEK). Fifty male workers from a large magnetic videotape factory participated in this study. Personal air samples were collected using 3M organic vapor monitors and analysed for MEK by gas chromatography with flame ionisation detector (FID). 10 mL of urine; blood (1 mL) and exhaled air were also collected at the end of an 8-hour workshift. The headspace GC method was applied for measurement of urinary and blood MEK. MEK in expired air was analysed directly by using a GC/FID.The correlation coefficients (r) between environmental MEK and all other biological parameters measured show significant positive relationships. The r for environmental MEK and urine MEK was 0.84; for blood 0.73 and for breath 0.64. The correlation coefficients between blood and urine was 0.72; blood and breath was 0.88 and urine and breath 0.60. These findings suggest that measurements of unmetabolised MEK in blood, exhaled air and urine can be used for biological monitoring of MEK exposure. Nevertheless, laboratory methodological assessment is in favour of measuring urinary MEK as it is non-invasive and does not have to be analysed immediately after collection.

The detection of aerosol propellants in body fluids and tissue by gas chromatography-mass spectrometry

The increased incidence of aerosol abuse in recent years has led to the development of a method for the detection of halogenated hydrocarbons in body fluids and tissue compatible with other routine methods. The use of the method in two background studies and a case investigation is described.

Driving under the influence of toluene

Toluene is the most common volatile used for sniffing among adolescents. During 1983-1987, 114 drivers were arrested in Norway with blood toluene concentrations (BTCs) greater than 10 microM. Only four of these drivers were women. The age range was 15-34 years, and the mean age was 21. The mean BTC was 109 microM. There was no simple relation between blood toluene concentration and degree of impairment, however, most drivers with BTCs greater than 100 microM were considered as impaired or probably impaired by toluene. In a five year prospective study of rearrests among drivers arrested for driving after toluene sniffing, 12 out of 15 drivers were rearrested. They were responsible for 40 cases of suspected driving under influence of toluene, alcohol, or other drugs. The blood levels of toluene determined in this study must be regarded as minimum concentrations, since the toluene concentration fell rapidly in samples stored at 4 degrees C or 23 degrees C. Blood samples from drivers suspected of driving under influence of toluene must therefore be kept frozen.

Chemical toxicology for the coroner

Toxicology results from all 302 coroners' cases referred to the supraregional unit at Beaumont Hospital over the one year period December 1987 to November 1988 are detailed. Clinical details were provided in 69.5% and formed the basis for the formation of four groups; road traffic accidents, suicides, possible suicides and possible carbon monoxide poisonings. All tests reported were instigated by the referring pathologist on behalf of the coroner. Alcohol was measured in all except 11 patients and a positive result was found in 44%. Drug screens were performed in 68.5% of cases with a positive finding in 30%. At least one positive result was found in 61.9% of the total. In the 60.4% of 53 road accident victims where alcohol was found, the median value was 117 mg/dl. COHb was measured in 23 cases and the median saturation was 45%. There were 12 suicides and agents found included paraquat, CO, cyanide, pancuronium bromide, and amitriptyline. Alcohol levels greater than 120 mg/dl were present in seven. In the 22 cases of suspected suicide, 77.3% were positive for drugs and more than one substance was found in 45.4%.

Rapid headspace gas chromatographic method for the determination of liquid/gas partition coefficients

A rapid, efficient and low-cost headspace technique useful for the determination of liquid/gas partition coefficients of gases and volatile substances of low and intermediate solubility is described. The equilibration step is carried out at constant pressure using glass syringes, with a ratio of liquid/gas phase volumes of ca. 1:3; after 30 min at the desired temperature, the headspace is recovered by transfer into another syringe and analyzed by gas chromatography. A study of the partition coefficients in water at 37 degrees C of 27 volatile compounds demonstrated that the method is fully applicable for all gases, with exception of those with a partition coefficient higher than 300.

Diagnosis and treatment of acute poisoning with volatile substances

1. The acute toxicity of many volatile compounds is similar, being more related to physical properties than to chemical structure. 2. Volatile substance abusers experiences euphoria and disinhibition but this may be followed by nausea and vomiting, dizziness, coughing and increased salivation; cardiac arrhythmias, convulsions, coma and death occur in severe cases. 3. Laboratory analysis of blood and urine samples collected up to 24 h post-exposure may be helpful if the diagnosis of volatile substance abuse is in doubt. 4. There is only a weak correlation between blood toluene and 1,1,1-trichloroethane concentrations and the clinical features of toxicity, possibly because of rapid initial tissue distribution and elimination. 5. Recovery normally occurs quickly once exposure has ceased but support for respiratory, renal or hepatic failure may be needed as well as treatment for cardiac arrhythmias. Therapy with intravenous acetylcysteine should be considered in cases of acute carbon tetrachloride poisoning.

An introduction to the practice, prevalence and chemical toxicology of volatile substance abuse

1. Volatile substance abuse is largely a teenage practice; it is estimated that in the UK 3.5-10% of young people have at least experimented and that 0.5-1% are current users. 2. The products abused are many and varied but only about 20 chemical compounds, notably toluene, chlorinated solvents such as 1,1,1-trichloroethane, fuel gases such as butane and aerosol propellants, are commonly encountered. 3. The acute hazard varies with the compound, product and mode of abuse. Mortality in the UK is now about 100 per year, from all social classes, 90% of whom are male. 4. Chronic toxicity is difficult to assess, partly because of the diversity of products abused. However it is clear that some long-term abusers suffer permanent damage to the central nervous system, heart, liver and kidney. 5. Toxicological analysis may be relied upon for confirmation of diagnosis, providing attention is paid to the kinetics of excretion and stability in the sample. 6. Responses include codes of practice for the sale of products and educational strategies; legislation has also been enacted. There is little evidence that any of these measures have made a significant impact on the problem.

Kinetic determination of propranolol in tablets by oxidation with ceric sulphate

A simple and accurate kinetic method for the determination of propranolol has been developed. Cerium(IV) sulphate (0.5 M) is used to oxidize propranolol in 2 M sulphuric acid at room temperature to the ketone form that absorbs light at a lambda max of 525 nm. The fixed-concentration method is used by recording the exact time, t(s), taken for the reaction to reach a fixed absorbance of 0.100. The unknown concentration, c(M), of propranolol is calculated from the equation: l/t = 0 0.000217 + 0.03 c. The method has been applied to the determination of propranolol in proprietary tablets and the results were compared with those obtained by the B.P. and other standard methods.

Effects of toluene on protein synthesis and the interaction with ethanol in hepatocytes isolated from fed and fasted rats

The effects of three different concentrations (about 10, 100 and 1000 microM) of toluene on protein synthesis were studied in hepatocytes isolated from fed and fasted rats after 60 and 120 min. of incubation. The interaction between ethanol (60 mM) and the low and high toluene concentrations were also tested. To measure protein synthesis, 14C-valine was used as the precursor amino acid. Total valine concentration was 2 mM to ensure near-constant specific radioactivity of precursor. Toluene concentrations were measured by head-space gas chromatography. Protein synthesis was unchanged in the presence of low toluene concentrations. Intermediate toluene concentration decreased protein synthesis by about 20% and high toluene concentration decreased protein synthesis by about 60%. Protein synthesis was similar in cells from fed and fasted rats. Ethanol alone inhibited protein synthesis by 20-30%, more in fasted than in fed rats. Toluene and ethanol in combination inhibited protein synthesis additively. The high toluene concentration with or without ethanol appeared to inhibit synthesis/secretion of export proteins in hepatocytes from fasted rats. In conclusion, our study indicates that toluene in relatively high concentrations inhibits general protein synthesis in isolated rat hepatocytes. Toluene and ethanol seems to inhibit protein synthesis additively.

Analytical toxicology

1. Major advances in analytical toxicology followed the introduction of spectroscopic and chromatographic techniques in the 1940s and early 1950s and thin layer chromatography remains important together with some spectrophotometric and other tests. However, gas- and high performance-liquid chromatography together with a variety of immunoassay techniques are now widely used. 2. The scope and complexity of forensic and clinical toxicology continues to increase, although the compounds for which emergency analyses are needed to guide therapy are few. Exclusion of the presence of hypnotic drugs can be important in suspected 'brain death' cases. 3. Screening for drugs of abuse has assumed greater importance not only for the management of the habituated patient, but also in 'pre-employment' and 'employment' screening. The detection of illicit drug administration in sport is also an area of increasing importance. 4. In industrial toxicology, the range of compounds for which blood or urine measurements (so called 'biological monitoring') can indicate the degree of exposure is increasing. The monitoring of environmental contaminants (lead, chlorinated pesticides) in biological samples has also proved valuable. 5. In the near future a consensus as to the units of measurement to be used is urgently required and more emphasis will be placed on interpretation, especially as regards possible behavioural effects of drugs or other poisons. Despite many advances in analytical techniques there remains a need for reliable, simple tests to detect poisons for use in smaller hospital and other laboratories.

Screening of volatile compounds present in human blood using retention indices in gas chromatography

The retention index in gas chromatography was introduced to screen volatile compounds in blood. Sixty-one organic compounds with high volatility were determined using a gas chromatograph with a flame ionization detector and a packed column system with 10% OV-17. Porapak P was used as a supplementary column for determining alcohol. Detection limits were determined for several substances. This method was used to analyse blood samples obtained at autopsy from patients suspected of solvent abuse. This approach proved to be superior to conventional gas chromatography in that mixed unknown volatiles in the blood could be identified simply and rapidly.

Survival after massive ingestion of carbon tetrachloride treated by intravenous infusion of acetylcysteine

A 61-year-old man ingested a large amount of carbon tetrachloride, well in excess of the adult lethal dose. The level of the compound was assayed in his blood and the levels were the highest ever recorded by the Guy's Hospital Poisons Unit. He was treated by intravenous infusion of acetylcysteine and survived with relatively mild clinical and biochemical evidence of toxicity. Possible reasons for his survival are discussed, as are the implications for the management of future cases.

Quantitative analysis of common anaesthetic agents

A summary of chromatographic (e.g. gas chromatography, high-performance liquid chromatography) and non-chromatographic (e.g. radioimmunoassay, enzyme-multiplied immunoassay) analytical techniques suitable for the quantitative analysis of the most popular inhalational (halothane, methoxyflurane, enflurane, isoflurane and nitrous oxide), intravenous (barbiturate, benzodiazepines, etomidate, althesin, morphine, fentanyl, alfentanil, sufentanil, droperidol and ketamine) general and amide-type local (lidocaine, mepivacaine, etidocaine and bupivacaine) anaesthetic agents and some of their metabolites, in biological material, is described. In the case of inhalational anaesthetics attention is also payed to pollution measurement and breath-to-breath monitoring.