ANALYST, JULY 1992, VOL. 117 1111 20 0 Detection and Identification of Volatile Substances by Headspace Capillary Gas Chromatography to Aid the Diagnosis of Acute Poisoning I - 1 1 I I I I I 1 Peter J. Streete and Manjit Ruprah National Poisons Unit, Guy's and Lewisham NHS Trust, Avonley Road, London SE14 5ER, UK John D. Ramsey Toxicology Unit, Department of Cardiological Sciences, St. George's Hospital Medical School, London SWl7ORE, UK Robert J. Flanagan" National Poisons Unit, Guy's and Lewisham NHS Trust, Avonley Road, London SE14 5ER, UK Headspace gas chromatography with split flame-ionization-electron-capture detection is a simple method of screening for a wide range of volatile substances in biological fluids. A 60 m x 0.53 mm i.d. thick-film (5 pm) f used-si I ica ca pi I la ry coated with SPB- 1 (Su pelc hem) with split f lame-ion ization-electron-ca ptu re detection provides a valuable alternative to packed columns in this work.Most commonly abused compounds, including many with very low boiling-points such as bromochlorodifluoromethane (BCF), butane, dimethyl ether, FC 11 , FC 12, isobutane and propane, can be retained and differentiated at an initial column temperature of 40 "C followed by programming to 200 "C. The total analysis time is 26 min. Retention and detector response data were generated for 244 compounds. Good peak shapes are obtained for polar analytes such as ethanol and injections of up to 0.30 cm3 of headspace can be performed with no discernable loss of efficiency. The sensitivity is thus at least as good as that attainable with packed columns.Of the commonly encountered compounds, only isobutane-methanol and paraldehyde-toluene are at all difficult to differentiate. Quantitative measurements can be performed either isothermally or by using the temperature programme. Keywords: Volatile substance abuse; biological samples; headspace gas chromatography; temperature programming; SPB- 1 capillary column There are now more than 100 deaths each year in the UK from volatile substance abuse (VSA, 'glue sniffing' , inhalant abuse, solvent abuse), mainly amongst adolescent males. 1 About 1.5-10% of UK secondary school children (boys and girls in approximately equal numbers) have experimented with VSA and about 1% are current users. Similar prevalence rates have been reported from many other countries within the last 10 years.In addition, there are a large number of reports not only of sudden death but also of long-term hazards associated with VSA.2 A wide range of compounds may be abused by inhalation (Table 1). However, the compounds encountered in UK VSA-related deaths are nowadays often very volatile substances such as those found in fuel gases, aerosol propel- lants and halon fire extinguishers (Fig. 1). The aerosol propellants used in the UK are at present mostly 'butane', although dimethyl ether either alone or as an azeotropic * To whom correspondence should be addressed. mixture with fluorocarbon (FC) 22 is used in other parts of Europe. A further compound, FC 134a, is under evaluation for use in medical aerosols.Analytical confirmation of the diagnosis of VSA is impor- tant , especially when investigating sudden death. Toxicologi- cal analyses may also be helpful if ingestion of solvents or solvent-based products is suspected or vapours may have been inhaled accidentally. Headspace sample preparation together with temperature-programmed gas chromatography (GC) and split flame-ionization-electron-capture detection (FID-ECD) provides a simple method of screening for a wide range of volatiles in biological specimens. Ramsey and Flanagan3 used a packed column (2 m x 2 mm i.d., 0.3% m/m Carbowax 20M on Carbopack C) programmed from 35 to 175 "C. On-column septum injections of up to 0.40 cm3 of headspace could be performed and thus good sensitivity (of the order of 0.1 mg dm-3 or better using 0.20 cm3 of sample) could be obtained.Moreover, most compounds of interest could be retained without resort to sub-ambient operation and the system could be used isothermally at an appropriate temperat- ure for quantitative analyses. Disadvantages included the poor resolution of some very volatile substances, the long total analysis time (40 min) and variation in the peak shape given by alcohols between different batches of column packing. Bonded-phase wide-bore capillary columns permit rela- tively large-volume septum injections and can offer advan- tages of improved efficiency, reproducibility and reliability. We have found that a 60 m x 0.53 mm i.d. fused-silica capillary coated with the dimethylpolysiloxane phase SPB-1(5 ym film thickness) offers many advantages over the packed column described above.In particular, improved resolution of very volatile compounds is obtained even at an initial temperature of 40 "C, the total analysis time can be reduced to 26 min and good peak shapes are obtained even for alcohols. Septum injections of up to 0.30 cm3 of headspace can be performed with no noticeable effect on column efficiency, hence the sensitivity is at least as good as that attainable with a packed column. The aim of this paper is to present retention1112 ANALYST, JULY 1992, VOL. 117 Table 1 Some volatile compounds which may be abused by inhalation (cfi, ref. 2) Aliphatic hydrocarbons- Acetylene (ethyne) Butane* Isobutane (2-methylpropane)* Hexanet Propane* Benzene (benzol) Toluene (methylbenzene, phenylmethane, toluol) Xylene (dimethylbenzene, xylol)$ Mixed hydrocarbons- Petrol (gasoline)$ Petroleum ethers (light petro1eums)fl Bromochlorodifluoromethane (BCF, FC 12B1) Carbon tetrachloride (tetrachloromethane) Chlorodifluoromethane (FC 22) Chloroform (trichloromethane) Dichlorodifluoromethane (FC 12) Dichloromethane (methylene chloride) 172-Dichloropropane (propylene dichloride) Enflurane (2-chloro-l,1 ,2-trifluoroethyl difluoromethyl ether) Fluorotrichloromethane (FC 11) Halothane (Zbromo-2-chloro-1 , I, 1-trifluoroethane) Isoflurane (l-chloro-2,2,2-trifluoroethyl difluoromethyl ether) Methoxyflurane (2,2-dichloro-1 ,l-difluoroethyl methyl ether) Monochloroethane (ethyl chloride) Tetrachloroethylene (perchloroethylene) 1,l71,2-Tetrafluoroethane (FC 134a) 1,1,l-Trichloroethane (methylchloroform, Genklene) Trichloroethylene (trike, Trilene) 1,1,2-Trichlorotrifluoroethane (FC 113) Acetone (dimethyl ketone, propanone) Butanone (butan-2-one7 methyl ethyl ketone, MEK) Diethyl ether (ethoxyethane) Dimethyl ether (DME, methoxymethane) Ethyl acetate Methyl acetate Methyl tert-butyl ether (MTBE) Methyl isobutyl ketone (MIBK, isopropylacetone, 4-methylpen- Nitrous oxide (dinitrogen monoxide , 'laughing gas') * Components of liquefied petroleum gas (LPG).t Commercial hexane is a mixture of hexane and heptane with small amounts of some higher aliphatic hydrocarbons. $ Mainly m-xylene (173-dimethylbenzene). $ Boiling-point range 40-200 "C, atmospheric pressure. fl Mixtures of pentanes, hexanes, etc., with specified boiling-point Aromatic hydrocarbons- Halogenated compounds- Oxygen compounh- tan-2-one) ranges (e.g., 40-60 "C).and reproducibility data obtained using the SPB-1 capillary column and to illustrate the use of this column in case work. Experimental Gas Chromatography The gas chromatograph (Hewlett-Packard Model 5890) was fitted with a Hewlett-Packard splitless capillary septum injector. The column was a 60 m x 0.53 mm i.d. fused-silica capillary coated with SPB-1 (5 pm film) (Supelchem UK, Saffron Walden, Essex, UK). The carrier gas was helium (flow rate 8.6 cm3 min-1). The injector and detector temperatures were 150 and 275 "C, respectively. The column oven, after a 6 min isothermal period, was programmed from 40 to 80 "C at 5 "C min-1 and then to 200 "C at 10 "C min-1 (total analysis time 26 min).Detection was by split FID-63Ni constant- current ECD (SGE outlet splitter system OSS-2, splitting ratio about 5 : 1). The hydrogen and air (FID) inlet pressures were Tabie 2 Preparation of the qualitative standard mixture (a) Qualitative standard mixture*- Compound Volume addedcm3t BCF Butane Dimethyl ether Isobutane FC 11 FC 12 FC 113 Propane 0.005 $ 1.0 $ 0.02 0.3 0.5 $ (b) Liquid components mixture§- Compound Volume addedcm3 Acetone Butanone Carbon tetrachloride Chloroform Ethanol Ethylbenzene Halothane Hexane Methyl isobutyl ketone Propan-2-01 Tetrachloroeth ylene Toluene 1 , 1 , 1-Trichloroethane 171,2-Trichloroethane Trichloroethylene 2,2,2-Trichloroethanol 7.5 5.0 0.05 0.5 5.0 2.5 0.1 5.0 2.5 5.0 0.025 2.5 0.25 1 .o 0.25 0.015 * Prepared in 125 cm3 gas sampling bulb.7 Volume of vapour phase in headspace vial. $2.0 cm3 of commercial 'butane' added (cf. , Table 1). § Add 0.01 cm3 to mixture of gaseous components in gas sampling bulb as in (a). 100 kPa (15 lb in-2) and 150 kPa (22 lb in-z), respectively. The ECD purge (nitrogen) flow rate was about 35 cm3 min-l. Data capture was by means of Hewlett-Packard 3396A recording integrators. The column was conditioned by programming from 30 to 260 "C with carrier flow at 2 "C min-1 and held for 16 h before use. Establishment of Retention Data Pure compounds were initially sampled in the vapour phase. However, direct liquid injection was employed for compounds that were not sufficiently volatile at 60 "C. Generally the amount of compound injected was sufficient to give full-scale deflection (FSD) or thereabouts at the detector sensitivities normally used in sample analyses (FID 80 pA FSD, ECD 2 kHz FSD).The ECD responses were coded as nil (0), poor (1) or good (2). Retention times were measured from the injection point and were also calculated relative to 1,1,2- trichloroethane. Kovdts retention indices were calculated from the data generated in the temperature programme by applying the following equation during the isothermal period or during the individual ramps of the programme:4*5 where RZ(x) = retention index of x , z = number of carbon atoms in alkane eluting before x , RT(x) = retention time of x , RT(z) = retention time of z, and RT(z + 1) = retention time of alkane with z + 1 carbon atoms eluting after x .Qualitative Standard Mixture A qualitative standard mixture was analysed prior to sample analyses. This mixture was prepared by adding the appro- priate volume of the gaseous components [Table 2(a)] toANALYST, JULY 1992, VOL. 117 1113 a clean, sealed, 125 cm3 gas-sampling bulb (Supelco 2-2146) and adding a portion (0.01 cm3) of the liquid components stock mixture [Table 2(b)]. This latter mixture was stable for at least 6 months when stored in a glass-stoppered vessel at -5 to -20 "C. Internal Standard Solution Ethylbenzene and 1 , l ,Ztrichloroethane were obtained from BDH (now Merck) (Poole, Dorset, UK) and tested by GC for the presence of contaminants, especially toluene and l , l , l - trichloroethane, before use. Approximately 50 mg of each compound were measured into 50 cm3 glass calibrated flasks containing outdated blood-bank whole blood.After thorough mixing, 1.0 cm3 of the 1,1,2-trichloroethane solution and 2.5 cm3 of the ethylbenzene solution were diluted to 100 cm3 using outdated blood-bank whole blood4e-ionized water (1 + 24) to give the working internal standard solution. The final ethylbenzene and 1,l ,2-trichloroethane concentrations were about 25 and 10 mg dm-3, respectively. This solution remained usable for not less than 2 years if stored in 5 cm3 portions at -5 to -20 "C in screw-topped glass bottles. Sample Preparation Blood and urine Internal standard solution (0.20 cm3) was added to a 7 cm3 glass septum vial (Schubert, Portsmouth, Hampshire, UK) using an air-displacement pipette (Eppendorf; BDH). The vial was then sealed with a crimped-on PTFE-lined silicone disc (Kontron, St.Albans, Hertfordshire, UK). The vial was incubated at 65 "C in a heating block and, after 15 min, a portion (0.10-0.30 cm3) of the headspace was taken using a gas-tight glass syringe (SGE), which had been warmed by being placed on the heating block (10 min), and injected onto the column. Subsequently, the sample (whole blood, plasma, serum or urine) (0.20 cm3) was added to the sealed vial using a 1.0 cm3 plastic disposable syringe fitted with a 1 in, 25 gauge Luer needle and, after at least 15 min, a second portion of the headspace was taken for analysis. After the injection the plunger was removed from the gas-tight syringe and the assembly placed on the heating block until the next injection to ensure evaporation of any remaining analytets).The syringe was rinsed occasionally with methanol to remove deposits and again allowed to dry before use. Tissues Samples of solid tissues were analysed as above after adding a proteolytic enzyme to the incubation mixture. Thus, 20-50 mg wet mass of tissue were dissected from the centre of the specimen, preferably whilst the specimen was frozen. Dupli- cate portions of the specimen were incubated (65 "C, 15 min) with internal standard solution (200 mm3) and about 1 mg of Subtilisin A (Novo, Windsor, Berkshire, UK) prior to the analysis of 0.10-0.30 cm3 of headspace as described above. The reagent blank analysis was performed in a separate vial. Products It is very important that all products sent for analysis are packaged and stored entirely separately from biological samples to prevent cross-contamination.Aerosols and fuel gases were analysed after releasing a portion of the product into a headspace vial. Adhesives and similar products were usually introduced into a glass vial. The vial was sealed and, after 1-15 min, a portion (0.05-0.10 cm3) of the headspace was taken for analysis. Liquids were analysed in the same way except that it was often possible to withdraw a portion (0.0054.05 cm3) of the headspace directly from the container. Quantitative Analyses Quantitative assays were performed in duplicate either isothermally or with a temperature programme and using the appropriate detector. If concentrations of ECD-responding compounds were very high it was sometimes more convenient to use FID for quantitative work.Assay calibration was by analysis of standard solutions prepared as described below; the same solutions were used in the analysis of blood and of tissue digests. Analyte concentrations in the range 0.1-10 or 0.5-50 mg dm-3 were usually adequate in cases of acute poisoning. Liquid analytes Calibration solutions were prepared by adding a known volume of the analyte to a calibrated flask containing 'blank' blood using a positive-displacement pipette and ascertaining the exact amount added by weighing. Appropriate volume to volume dilutions were then performed, taking care to mini- mize losses of analyte by handling reagents and glassware at 4 "C and storing samples and standards at 4 "C with minimal headspace.6 Small (2 cm3) glass vials with caps lined with aluminium foil are convenient for performing standard dilutions.Portions of the standards were transferred into headspace vials for analysis as described above and a calibration graph of peak height ratio of analyte to internal standard against analyte concentration was prepared. Often either 1,1,2-trichloroethane or ethylbenzene could be used as the internal standard. Carbon tetrachloride and l,l,l-tri- chloroethane were best determined isothermally at a column temperature of 120 "C, while tetrachloroethylene, toluene, 2,2,2-trichloroethanol and trichloroethylene were best deter- mined at 140 "C. Gaseous analytes Calibration mixtures were prepared directly into headspace vials.7 Septum bottles of about 125 cm3 capacity were calibrated by weighing the amount of de-ionized water each could contain.Each bottle was then dried and filled with nitrogen. A piece of aluminium foil (about 1 cm2) was added to aid mixing and the vial was sealed. After recording atmospheric pressure, the pure analyte, usually supplied in a small cylinder, was transferred into a 125 cm3 glass gas sampling bulb fitted with a septum port (Supelco 2-2146) at atmospheric pressure. An appropriate volume of vapour was then taken from the gas sampling bulb using a gas-tight syringe and added to a calibrated septum bottle. Care was taken to ensure that the contents of all vessels remained at atmospheric pressure. Thus, if the volume of gas transferred was greater than 0.1 cm3 a short vent needle was inserted through the septum well away from the point of the gas-tight syringe needle.After thorough mixing, further dilutions were pre- pared as required. Finally, known volumes of diluted analyte vapour were transferred using a gas-tight syringe into head- space vials containing the same volume of 'blank' blood as used in sample analyses. A constant volume of appropriately diluted internal standard (2,2-dimethylpropane for butane) vapour was also added to the sample and standard vials. Results and Discussion Retention and Relative Detector Response Even with sub-ambient operation and temperature program- ming, many capillary columns elute very volatile compounds too quickly if less volatile components of interest are to elute at reasonable retention times.However, the 60 m thick-film SPB-1 column retained and resolved many very volatile compounds at an initial temperature of 40 "C while allowing a total analysis time of only 26 min. The reductions in costs and in the time taken in recycling which arise directly from the use of this relatively high starting temperature are considerable,1114 ANALYST, JULY 1992, VOL. 117 t % 2 e 0 P LL t fn 0 P 2 n ow 21 I 24 1 16 17 15 18 0 5 10 15 20 25 Timelmin Fig. 2 a ) and ( b ) Analysis of the qualitative standard mixture (cf., Table 25 with detector sensitivities (FSD) (a) FID 3.2 nA and ( 6 ) ECD 64 kHz. Column, 60 m X 0.53 mm i.d. SPB-1 (5 pm film); oven temperature, 40 "C (6 min), then to 80 "C at 5 "C min-1, then to 200 "C at 10 "C min-1; and injection volume, =0.010 cm3.Peaks: 1 = propane, 2 = FC 12,3 = dimethyl ether, 4 = isobutane, 5 = butane, 6 = BCF, 7 = ethanol, 8 = acetone, 9 = propan-2-01,lO = FC 11,11 = FC 113, 12 = halothane, 13 = butanone, 14 = hexane, 15 = chloroform, 16 = 1,1,l-trichloroethane, 17 = carbon tetrachloride, 18 = trichloroethylene, 19 = meth 1 isobutyl ketone, 20 = 1,1,2- trichloroethane (internal standardr, 21 = toluene, 22 = tetrachlo- roethylene, 23 = 2,2,2-trichloroethanol, and 24 = ethylbenzene (internal standard) especially if liquid carbon dioxide cooling would otherwise have been necessary. It is of interest that Pekari et a1.8 used two linked 30 m x 0.53 mm i.d. capillaries (both 2.65 pm film thickness) coated with 100% dimethylpolysiloxane and 5% phenyl-95% dimethylpolysiloxane, respectively, in the deter- mination of benzene and toluene in blood headspace. They found that a programmed run to 200 "C was needed to obtain optimum sensitivity and selectivity, but that the use of the effectively 60 m 'medium film' column allowed a starting temperature of 50 "C to be used.The programme was run each day before undertaking sample analyses in order to remove any contaminants that had accumulated since the system was last used. The analysis of the qualitative standard mixture (Table 2) is illustrated in Fig. 2. Note especially the good peak shapes given by ethanol and propan-2-01 and the absence of a peak derived from the septum (cf., ref. 3). No deterioration in peak shape has been observed in routine use over a 1 year period. The SPB-1 column is operated well below its maximum recommended temperature (320 "C) so the column life should be long.Retention and detector response data for 244 compounds are given in Table 3. Compounds that were injected as liquids are identified by asterisks; these substances have been included in the database primarily to facilitate analysis of products and other non-biological specimens. Compounds that did not elute during the programme generally had boiling-points (atmo- spheric pressure) at 170 "C or above and retention indices (n-alkane) on SE-30, OV-1 or OV-101 packed columns of lo00 or more (cf., Table 3). Amongst the compounds found not to elute were camphor, 1-chlorooctane, cycloheptanone, decane, 1 ,2-dichlorobenzene, 1,6dichlorobenzene, 2,6- dimethylheptan-4-one, ethchlorvynol, 2-ethylhexan-1-01, 2-ethylhexyl acetate, hexachloroethane, 4-methylbenzal- dehyde, N-methylformamide, nonan-2-one, nonan-5-one, octan-1-01 and octylamine. The injection of hydrogen (retention time 2.49 min, relative retention with respect to 1 ,2,2-trichloroethane 0.134) pro- vided a measure of the void volume of the system (retention time of methane 2.52 min; cf., Table 3).There was a slight difference in the absolute retention time of compounds which responded at each detector because of the presence of the effluent splitter. Retention times were calculated relative to 1 , l ,2-trichloroethane as this compound gave a response on both detectors at the sensitivities normally employed. However, the retention data quoted in Table 3 were derived from the ECD for compounds responding on that detector.The classification of ECD response (Table 3) is empirical and is simply a guide to aid peak assignment. Compounds responding strongly on the ECD were primarily halogenated substances, but many compounds containing nitro or keto moieties also responded. Other substances such as ally1 isothiocyanate and dinitrogen monoxide also showed a good response. In contrast, the response to some halogenated compounds such as 1,1,1,2-tetrafluoroethane was relatively poor and certain ketones, e.g., the heptanones, showed no response. The retention data have proved highly reproducible in routine use over a 6 month period (Table 4) and should be applicable to other SPB-1 columns (and indeed to other dimethylpolysiloxane-coated capillaries) of similar dimen- sions and film thickness.However, the carrier gas flow rate might have to be adjusted to give retention data identical with those given in Table 3. We find that the retention time is more convenient than the retention index when assessing retention of unknowns. Franke et al.9 and others have emphasized the value of retention indices when transferring GC retention data between systems. However, Franke et al. themselves used retention indices based on alkan-1-01s (primary n-alkane alcohols) rather than on n-alkanes when using columns packed with Carbopack materials in the analysis of solvents and other volatiles. This was a strange choice as primary alcohols often give tailing peaks on such columns and thus give poorly reproducible retention data.The Kovhts retention indices (n-alkane) calculated for each compound with the temperature programme on the SPB-1 column are given in Table 3(a). Literature values for Kovhts retention indices on SE-30, OV-1 or OV-101 packed col- umns,3,*0 if available, are also given in this table; if two different packed column retention indices were reported, the mean was taken. It was found that only compounds with a retention index of <loo0 eluted from the SPB-1 column with the temperature programme used. Therefore, in order to calculate the retention indices for compounds eluting between 23.56 min (retention time of nonane) and 26.00 min, it was necessary to ascertain the retention time of decane. This was measured by continuing the final ramp for a further 2 min (retention time of decane 26.06 min).The retention indices of homologous series of acetates, formates, primary alcohols, aldehydes and alk-1-enes on the SPB-1 column are plotted inANALYST, JULY 1992, VOL. 117 1115 Table 3 Retention and relative detector response data on the SPB-1 column system (see legend to Fig. 2 for chromatographic conditions)* (a) Alphabetical order- Compound Acetaldehyde Acetone Acetonitrile Acetonylacetone: see Hexane-2,5-dione Acetylacetone: see Pentane-2,Cdione Acetylene Acrylonitrile Allyl glycidyl ether Allyl isothiocyanate Amy1 . . .: see Pentyl . . . 3CF: see Bromochlorodifluoromethane 3enzene 3enzaldehyde 3enzonitrile 3icyclo[4.3 .O]nonane 3romoacetonitrile 3romobenzene 3romochlorodifluoromethane 3romochloromethane !-Bromo-2-chloro- 1 , l , 1-trifluoroethane: 3romodichloromethane l-Bromo-2,3-epoxypropane 3 romo form 3romomethane 1-Bromopropane 3romotrichloromethane 3romotrifluoromethane 3utanal 3utane-2,3-dione 3utane 3utan-1-01 3utan-2-01 ert-Butanol: see 2-Methylpropan-2-01 3utanone 3ut- 1-ene 3utyl acetate 3utyl chloride: see 1-Chlorobutane 3utyl formate 3utyl iodide: see I-Iodobutane 3utyl nitrite 3utyraldehyde: see Butanal see Halothane Capronaldehyde: see Hexanal Caprylene: see Oct-1-ene Carbon disulfide Carbon tetrachloride Chloral hydrate 1-Chlorobutane Chlorbutol: see Chlorobutanol Chlorobenzene Chlorobutanol 2-Chloro-1,l-difluoroethane 2-Chloro-1 ,I-difluoroethylene Chlorodifluoromethane l-Chloro-2,3-epoxypropane Chloroethane: see Monochloroethane 2-Chloroethanol Chloroform 1-Chloro-2-met h ylbenzene 1-Chloro-3-methylbenzene 1-Chloro-4-methyl benzene 2-Chlorophenol 1-Chloropropane 2-Chloro-l,l,l-trifluoroethane l-Chlor0-2,2,2-trifluoroethyl difluoromethyl ether: 2-Chloro-l,1,2-trifluoroethyl difluoromethyl ether: Cryofluorane: see 1,2-Dichlorotetrafluoroethane see Isoflurane see Enflurane RT/min 3.59 5.66 5.22 2.63 6.50 22.62 22.31 14.39 24.75 25.16 25.48 17.65 24.45 4.07 11.40 16.16 19.54 22.82 4.47 12.24 18.98 2.77 9.98 9.72 4.09 14.08 10.80 10.18 3.94 20.36 17.02 12.41 8.03 14.70 16.60 13.64 21.90 25.44 3.41 3.46 3.14 16.42 13.57 11.65 24.96 25.03 25.05 25.83 8.31 3.73 RRT 0.192 0.303 0.279 0.141 0.348 1.211 1.192 0.770 1.325 1.347 1.364 0.943 1.306 0.217 0.609 0.863 1.044 1.219 0.239 0.654 1.014 0.148 0.534 0.519 0.219 0.754 0.578 0.545 0.211 1.090 0.911 0.663 0.429 0.785 0.887 0.730 1.170 1.359 0.182 0.185 0.168 0.877 0.725 0.622 1.336 1.337 1.343 1.380 0.444 0.199 ECD 0 1 0 0 0 0 2 0 0 0 0 2 2 2 2 2 2 2 2 2 2 2 0 2 0 0 0 1 0 0 0 2 1 2 2 2 1 2 1 1 2 2 2 2 1 1 1 2 1 1 Calc.352 460 443 165 492 869 585 655 948 965 977 725 936 398 598 690 773 875 414 614 859 222 568 563 400 650 585 572 386 795 708 617 527 661 698 641 844 976 335 339 309 695 640 603 956 959 960 992 533 365 Lit. 372 469 455 - 590 880 660 956 - - - 945 405 660 715 805 911 - - 810 - - - 400 651 624 579 390 794 701 608 524 659 705 642 860 949 - - - 720 643 605 - - - - 570 375 Retention index Formula mass 44.1 58.1 41.1 26.0 53.1 114.2 99.2 78.1 106.1 103.1 124.2 120.0 157.0 165.4 129.4 163.8 137.0 252.8 94.9 123.0 198.3 148.9 72.1 86.1 58.1 74.1 74.1 72.1 56.1 116.2 102.1 103.1 76.1 153.8 165.4 92.6 112.6 177.5 100.5 98.5 86.5 92.5 80.5 119.4 126.6 126.6 126.6 128.6 78.5 118.5 B.p.PC 21 57 82 -81 77 154 151 80 179 191 167 627 156 -3 68 90 136 149 -94 71 103 -58 75 89 -1 117 100 80 -6 125 107 78 47 77 98 79 131 167 - 10 - 18 -41 118 129 61 159 162 162 175 47 7 CAS Registry No.75-07-0 67-64-1 75-05-8 74-86-2 107-13-1 106-92-3 57-06-7 71-43-2 100-52-7 100-47-0 496-10-6 590-17-0 108-86-1 353-59-3 74-97-5 75-27-4 3132-64-7 75-25-2 74-83-9 106-94-5 75-62-7 75-63-8 123-72-8 43 1-03-8 106-97-8 71-36-3 78-92-2 78-93-3 106-98-9 123-86-4 592-84-7 544-16-1 75-15-0 56-23-5 302-17-0 106-69-3 108-90-7 57-15-8 75-68-3 359-10-4 75-45-6 106-89-8 107-07-3 67-66-3 95-49-8 106-41-8 106-43-4 95-57-8 540-54-5 75-88-71116 ANALYST, JULY 1992, VOL.117 Table 3 Retention and relative detector response data on the SPB-1 column system (see legend to Fig. 2 for chromatographic conditions) *-continued (a) Alphabetical order- Compound Cumene Cyanogen bromide Cyclohexane Cyclohexanol Cyclohexanone Cyclohexene C yclopropane Diacetone alcohol: see 4-Hydroxy-4-methylpentan-2-one Diacetyl: see Butane-2,3-dione Dibromodifluoromethane 1 ,ZDibromoethane Dibromomethane 2,2-Dichloro- 1,l-difluoroethyl methyl ether: see Methoxyflurane Dichlorodifluoromethane 1,l-Dichloroethane 1,2-Dichloroethane 1,l-Dichloroethylene 1,2-Dichloroethylene (both isomers) Dichloromethane 1,2-Dichloropropane 1,3-Dichloropropane 1,3-Dichloropropan-2-ol 1,2-Dichlorotetrafluoroethane Diethylamine Diethyl ether Diethyl ketone: see Pentan-3-one 1,l-Difluorotetrachloroethane 1,2-Difluorotetrachloroethane Diisopropyl ether Dimethoxymethane: see Methylal N, N-Dimeth ylacetamide Dimethyl disulfide: see Methyl disulfide Dimethyl ether N, N-Dimeth ylformamide 2,5-Dimethylfuran Dimethyl ketone: see Acetone 2,2-Dimethylpropane 2,6-Dimethylpyridine Dimethyl sulfide: see Methyl sulfide Dimethyl sulfoxide Dinitrogen monoxide: see Nitrous oxide Dipropyl ketone: See Heptan-4-one D i o x a n e 1,3-Dioxolane DME: see Dimethyl ether DMF: see N,N-Dimethylformamide DMSO: see Dimethyl sulfoxide Enflurane Epibromohydrin: see l-Bromo-2,3-epoxypropane Epichlorohydrin: see l-Chloro-2,3-epoxypropane 1,2-Epoxybutane Ethane Ethanol EthanolamineS 2-Ethoxyethanol 2-Ethoxyethyl acetate Ethyl acetate Ethylamine Ethylbenzene Ethyl Cellosolve: see 2-Ethoxyethanol Ethyl chloride: see Monochloroethane Ethylene Ethylene chlorohydrin: see 2-Chloroethanol Ethylene glycol$ Ethylene oxide Ethyl formate Ethyl iodide: see Iodoethane CEthylrnorpholine RT/min 24.19 6.25 14.91 22.77 22.90 15.69 8.29 6.12 20.20 15.80 3.18 9.57 13.09 7.28 9.19 7.45 15.87 19.20 22.74 3.59 9.53 6.69 16.77 16.90 11.43 21.61 3.34 18.47 16.53 4.32 22.62 19.97 16.16 11.13 6.14 10.63 2.69 4.80 13.75 16.38 22.83 11.42 4.30 22.38 2.63 15.15 4.22 6.82 22.68 RRT 1.295 0.334 0.798 1.219 1.226 0.840 0.444 0.327 1.079 0.844 0.170 0.511 0.699 0.389 0.491 0.398 0.848 1.026 1.215 0.192 0.510 0.358 0.896 0.903 0.612 1.157 0.179 0.989 0.885 0.231 1.211 1.069 0.865 0.596 0.328 0.569 0.144 0.257 0.736 0.877 1.222 0.611 0.230 1.198 0.141 0.811 0.226 0.365 1.214 ECD 0 2 0 0 1 0 0 2 2 2 2 2 2 2 2 2 1 2 2 2 0 0 2 2 0 0 0 0 1 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Calc. 925 482 666 874 878 681 533 477 790 683 313 559 630 512 552 515 684 765 873 352 559 499 702 704 598 835 328 746 697 409 869 784 690 592 478 582 200 427 643 694 876 598 408 861 165 670 405 52 1 871 Lit.905 664 899 875 703 - - - 823 733 305 563 63 1 556 515 - - - 885 361 515 785 730 594 - - - - 697 - - - 696 635 462 600 200 42 1 780 701 874 596 860 - - 772 400 545 - Retention index Formula mass 120.2 105.9 84.2 100.2 98.1 82.1 42.1 209.8 187.9 173.8 120.9 99.0 99.0 96.9 96.9 84.9 113.0 113.0 129.0 170.9 73.1 74.1 203.8 203.8 102.2 87.1 46.1 73.1 96.1 72.2 107.1 78.1 88.1 74.1 184.5 72.1 30.1 46.1 61.1 90.1 132.2 88.1 45.1 106.2 28.1 62.1 44.1 74.1 115.2 B .p.PC 152 62 81 161 156 83 -33 25 133 98 - 30 58 83 61 60 40 96 122 174 4 56 35 92 93 69 167 - 24 153 94 10 144 191 101 76 57 65 -88 79 70 135 156 77 17 136 -104 198 11 53 139 CAS Registry No. 98-82-8 506-68-3 110-82-7 108-93-0 108-94- 1 110-83-8 75-19-4 75-61-6 106-93-4 74-95-3 75-71-8 75-34-3 107-06-2 156-59-2 540-59-0 75-09-2 78-87-5 142-28-9 96-23-1 76- 14-2 109-89-7 60-29-7 76-11-9 76-12-0 108-20-3 127-19-5 115-10-6 68-12-2 625-86-5 463-82-1 108-48-5 67-68-5 123-91-1 646-06-0 13838-16-9 106-88-7 74-84-0 64- 17-5 141-43-5 110-80-5 11 1-15-9 141-78-6 75-04-7 100-41-4 74-85-1 107-21-1 75-21-8 109-94-4 100-74-3ANALYST, JULY 1992, VOL.117 1117 Table 3 Retention and relative detector response data on the SPB-1 column system (see legend to Fig.2 for chromatographic conditions)*-continued (a) Alphabetical order- Retention index CAS RT/min RRT ECD Calc. Lit. mass B.p./”C No. Formula Registry 99 105-37-3 16.42 0.879 0 695 679 102.1 Compound Ethyl propionate Ethyl propyl ketone: see Hexan-3-one FC 11: see Fluorotrichloromethane FC 12: see Dichlorodifluoromethane FC 12B1: see Bromochlorodifluoromethane FC 22: see Chlorodifluoromethane FC 112: see 1,2-DifluorotetrachIoroethane FC 113: see 1,1,2-Trichlorotrifluoroethane FC 114: see 1,2-Dichlorotetrafluoroethane FC 134a: see 1,1,1,2-Tetrafluoroethane FC 142: see 2-Chloro-1 ,l-difluoroethane Fluorotrichloromethane Formaldehyde Formaldehyde dimethyl acetal: see Methylal Furfural 6.13 0.327 2.86 0.153 2 0 478 484 137.4 24 75-69-4 247 - 30.0 -20 50-00-0 806 825 96.1 162 98-01 - 1 20.74 1.108 1 Halothane 2,2,3,3,4,4,4-Heptafluorobutan-l-ol Heptanal Heptane Heptan- 1-01 Heptan-2-one Heptan-3-one Heptan-4-one Hept-l-ene Hexahydroindan: see Bicyclo[4.3.0]nonane Hexanal Hexane Hexane-2S-dione Hexan-1-01 Hexan-2-01 Hexan-2-one Hexan-3-one Hex-l-ene Hexyl acetate Hexyl formate 4-Hydroxy-4-methylpentan-2-one 8.76 0.468 9.25 0.494 23.05 1.234 16.70 0.894 24.88 1.332 22.79 1.220 22.62 1.211 22.27 1.192 16.18 0.866 543 553 883 700 953 874 869 857 690 533 883 700 955 880 857 - - - 197.4 200.1 114.2 100.2 116.2 114.2 114.2 144.2 98.2 50 103 153 98 176 152 148 144 94 151-67-7 375-01-9 11 1-71-7 142-82-5 11 1-70-6 110-43-0 106-35-4 123-19-3 592-76-7 19.82 1.061 11.51 0.616 23.25 1.242 22.12 1.184 19.95 1.068 19.45 1.041 19.33 1.035 10.89 0.583 25.83 1.383 23.84 1.276 21.17 1.131 0 0 1 0 0 0 0 0 0 0 1 78 1 600 890 852 784 77 1 768 587 992 911 820 - 600 894 860 786 787 78 1 - 100.2 86.2 114.1 102.2 102.2 100.2 100.2 84.2 144.2 130.2 116.2 130 69 188 157 140 127 124 64 170 155 168 66-25- 1 110-54-3 110-13-4 111-27-3 626-93-7 591-78-6 589-38-8 592-4 1-6 142-92-7 629-33-4 123-42-2 - 82 1 l-Iodobutane Iodoet hane Iodomethane l-Iodopropane Isoamyl... : see Isopentyl.. . Isobutane Isobutanol: see 2-Methylpropan-1-01 Isobutyl acetate Isobutylamine Isobutyl nitrite Isoflurane Isooctane Isopentyl acetate Isopentyl alcohol: see 3-Methylbutan-1-01 Isopentylamine Isopentyl nitrite (‘amyl nitrite’) Isoprene Isopropanol : see Propan-2-01 Isopropyl acetate Isopropylacetone: see Methyl isobutyl ketone Isopropyl formate Isopropyl nitrate Isovaleraldehyde: see 3-Methylbutanal 20.91 1.117 11.55 0.617 7.13 0.381 16.90 0.903 81 1 840 184.0 130 542-69-8 601 680 156.0 72 75-03-6 509 515 142.0 43 74-88-4 107-08-4 705 785 170.0 102 3.61 0.193 354 370 58.1 -12 75-28-5 0 19.00 1.017 10.95 0.586 10.37 0.555 5.52 0.295 16.31 0.873 22.34 1.196 759 754 116.2 118 110-19-0 588 - 73.1 69 78-81-9 576 - 103.1 67 542-56-3 454 - 184.5 49 26675-46-7 692 725 114.2 99 540-84- 1 884 130.2 142 123-92-2 859 16.42 0.879 15.87 0.848 6.91 0.370 0 2 0 695 - 87.2 95 107-85-7 684 680 117.2 98 110-46-3 504 - 68.1 34 78-79-5 14.10 0.755 0 650 648 102.1 89 108-21 -4 9.55 0.511 14.84 0.793 0 2 559 567 88.1 68 625-55-8 664 693 105.1 103 1712-64-7 Limonene 25.69 1.375 0 986 1053 136.2 177 138-86-3 MEK: see Butanone Meparfynol: see 3-Methylpent-l-yn-3-01 2-Mercaptoethanol Methane Methanol 2-Methoxyethanol 17.63 0.942 2.52 0.135 3.60 0.192 12.38 0.663 724 795 78.1 158 60-24-2 100 100 16.0 -161 74-82-8 353 49 1 32.0 65 67-56- 1 617 616 76.1 124 109-86-41118 ANALYST, JULY 1992, VOL.117 Table 3 Retention and relative detector resnonse data on the SPB-1 column system (see legend to Fig. 2 for chromatographic 1 conditions)*--continued (a) Alphabetical order- Compound Methoxyflurane Methyl acetate Methylal Methyl bromide: see Bromomethane 2-Methylbuta-l,3-diene: see Isoprene 3-Methylbutanal 2-Methylbutan-1-01 2-Methylbutan-2-01 3-Methylbutan-1-01 3-Methylbutan-Zone: see Methyl isopropyl ketone Methyl tert-butyl ether Methyl butyl ketone: see Hexan-Zone Methyl butyrate Methyl Cellosolve: see 2-Methoxyethanol Methylchloroform: see 1,l ,l-Trichloroethane Methyl cyanide: see Acetonitrile Meth ylcyclohexane Methylcyclopentane Methyl cyclopropyl ketone Methyl disulfide Methylene chloride: see Dichloromethane Methyl ethyl ketone: see Butanone Methyl formate 6-Methylhept-S-en-2-0ne 2-Methylhex-l-ene Methyl hexanoate Methyl iodide: see Iodomethane Methyl isobutyl ketone Methyl isopropyl ketone Methyl methacrylate 2-Methylpentane 3-Methylpentane 2-Methylpentan-2-01 4-Methylpentan-2-one: see Methyl isobutyl ketone Methylpentynol: see 3-Methylpent-l-yn-3-01 3-Methylpent-l-yn-3-01 2-Methylpropanal 2-Methylpropan-1-01 2-Methylpropan-2-01 Methyl propionate 2-Methylpropylamine: see Isobutylamine Methyl propyl ketone: see Pentan-2-one l-Meth ylpyrrole Methyl sulfide MIBK: see Methyl isobutyl ketone Monochloroethane Morpholine MTBE: see Methyl terr-butyl ether Neopentane: see 2,ZDimethylpropane Ni troethane Nitromethane l-Nitropropane 2-Nitropropane Nitrous oxide Nonane Octanal Octane Octan-2-01 Octan-Zone Octan-3-one Octan-4-one Oct-l-ene Oct-2-yne Paralde h yde Pentane-2,3-dione Pentane-2,Qdione Pentanal Pentane RT/min 17.04 7.30 7.08 13.43 17.63 12.96 17.45 9.60 16.94 17.82 13.11 16.85 18.07 4.28 25.24 16.05 25.50 17.60 13.71 16.48 9.90 10.61 17.45 16.42 8.46 12.22 7.14 12.33 17.56 7.12 4.77 19.77 12.47 7.98 17.00 15.27 2.66 23.56 25.70 20.57 25.65 25.39 25.29 24.99 20.17 22.57 19.28 15.37 19.17 15 .so 6.72 RRT 0.910 0.391 0.379 0.719 0.944 0.694 0.934 0.514 0.907 0.954 0.702 0.902 0.965 0.229 1.351 0.859 1.365 0.942 0.734 0.882 0.530 0.568 0.934 0.879 0.453 0.654 0.382 0.660 0.940 0.381 0.255 1.056 0.666 0.427 0.907 0.816 0.142 1.261 1.376 1.101 1.373 1.359 1.354 1.338 1.080 1.208 1.032 0.821 1.026 0.830 0.360 ECD 2 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 2 1 2 1 2 2 2 0 0 0 0 0 0 0 0 0 0 1 0 0 0 Retention index Formula Calc.Lit. 617 512 508 637 724 628 719 560 706 729 631 704 735 407 968 687 978 723 642 696 566 581 719 695 536 614 509 616 722 508 426 779 618 526 708 672 182 900 986 800 984 974 970 958 790 867 767 674 764 677 500 701 513 505 - - 636 720 - 723 748 650 730 - 499 725 - - 724 650 699 610 725 - 715 619 512 639 - 715 - 447 800 655 565 725 685 900 990 800 - - - - - 790 870 771 681 790 500 - mass 165.0 74.1 76.1 86.1 88.2 88.2 88.2 88.2 102.1 98.2 84.2 84.1 94.2 60.1 126.2 98.2 130.2 100.2 86.0 loo.1 86.2 86.2 102.2 98.1 72.1 74.1 74.1 88.1 81.1 62.1 64.5 87.1 75.1 61 .O 89.1 89.1 44.0 128.3 128.2 114.2 130.2 128.2 128.2 128.2 112.2 110.2 132.2 100. 1 100.1 86.1 72.2 B.p.PC 105 57 42 93 128 103 132 55 102 101 73 114 110 32 58 92 151 118 93 100 60 64 124 121 64 108 82 80 111 36 12 129 115 101 132 120 - 88 151 68 126 179 173 169 164 122 138 124 115 141 103 36 CAS Registry No. 7 6 - 3 8 - 0 79-20-9 109-87-5 590-86-3 137-32-6 75-85-4 123-5 1-3 1634-04-4 623-42-7 108-87-2 96-37-7 765-43-5 624-92-0 107-31-3 110-93-0 6094-02-6 106-70-7 108-10- 1 563-80-4 80-62-6 107 - 8 3 - 5 96-14-0 590-36-3 77-75-8 74-84-2 78-83-1 75-65-0 554-12-1 96-54-8 75-18-3 75-00-3 110-91-8 79-24-3 75-52-5 108-03-2 79-46-9 10024-97-2 11 1-84-2 124- 13-0 111-65-9 123-93-6 111-13-7 106-68-3 11 1-66-0 123-63-7 600-14-6 123-54-6 110-62-3 109-66-0ANALYST, JULY 1992, VOL.117 1119 Table 3 Retention and relative detector response data on the SPB-1 column system (see legend to Fig. 2 for chromatographic conditions)*-continued (a) Alphabetical order- Compound Pentan-1-01 Pentan-2-one Pentan-3-one Pent-1-ene Pentyl acetate Pentyl formate tert-Pentyl alcohol: see 2-Methylbutan-2-01 Perchloroethylene: see Tetrachloroethylene Perfluoropropane a-Pinene Piperidine Propanal Propane Propane-172-diol$ Propane-173-diol$ Propan-1-01 Propan-2-01 Propanone: see Acetone Propionaldehyde: see Propanal Propionitrile Propyl acetate Propylamine Propyl bromide: see 1-Bromopropane Propyl chloride: see 1-Chloropropane Prop ylene Propyl formate Propyl iodide: see 1-Iodopropane Pyridine Pyrrole Pyrrolidine Styrene Sulfur hexafluoride 1,1,2,2-Tetrabromoethane 1,1,1,2-TetrachIoroethane 1,1,2,2-Tetrachloroethane Tetrachloroe thylene Tetrachloromethane: see Carbon tetrachloride 1,1,1,2-Tetrafluoroethane Tetrahydrofuran THF: see Tetrahydrofuran Toluene Tribromomethane: see Bromoform 1 , 1,l-Trichloroethane 1,l ,2-Trichloroethane 2,2.2-Trichloroethanol Trichloroethylene Trichloromethane: Gxhloroform RT/min 18.74 15.07 15.58 6.28 23.31 20.87 6.08 24.81 18.81 5.77 3.05 17.09 20.29 8.61 6.04 8.57 16.51 7.60 2.99 11.84 17.65 17.97 15.21 23.18 2.58 25.50 21.85 23.33 20.89 2.76 12.31 19.14 13.56 18.72 22.29 16.25 1,l,l-Trichloro-2-methyli>\ropan-2-ol: see Chlorobutanol l72,3-Trich1oropropane 23.53 1 , 1 , 1-Trichloropropan-2-01 23.85 1 , 1,l -Trichlorotrifluoroethane 7.90 1 , 1,2-Trichlorotrifluoroethane 8.01 Trieth ylamine 15.84 2,2,2-Trifluoroethanol 5.17 2,2,2-Trifluoroethyl chloride: see 2-Chloro- Trifluoromethyl bromide: see Bromotrifluoromethane Trimethylene: see Cyclopropane 2,2,4-Trimethylpentane: see Isooctane 1,l ,l-trifluoroethane Valeraldehyde: see Pentanal y-Valerolactone Vinyl chloride Vin ylidine chloride m-Xylene o-Xylene p-Xylene RRT 1.003 0.807 0.834 0.336 1.248 1.117 0.325 1.328 1.007 0.309 0.163 0.915 1.086 0.461 0.323 0.459 0.884 0.407 0.160 0.634 0.945 0.962 0.814 1.241 0.138 1.362 1.167 1.246 1.116 0.148 0.659 1.025 0.724 1 .ooo 1.191 0.868 1.257 1.274 0.422 0.428 0.848 0.276 ECD 0 1 1 0 0 0 2 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 2 2 2 1 0 0 2 2 2 2 2 2 2 2 0 1 Retention index Formula Calc .753 669 678 483 892 810 476 950 755 464 300 710 793 539 474 539 696 518 283 606 725 733 671 887 135 978 843 892 81 1 219 615 763 639 752 858 69 1 899 912 525 527 684 441 Lit. 763 680 683 - - 772 - 942 782 300 745 820 57 1 530 - 580 696 - 3 10 603 725 755 695 890 - - 870 905 807 - 638 768 634 727 859 710 910 920 530 555 580 - mass 88.2 86.1 86.1 70.1 130.2 116.1 188.0 136.2 85.2 58.1 44.1 76.1 76.1 60.1 60.1 55.1 102.1 59.1 42.1 88.1 79.1 67.1 71.1 104.1 146.1 345.7 167.9 167.9 165.9 102.0 72.1 92.1 133.4 133.4 149.4 131.4 147.4 163.4 187.4 187.4 101.2 100.0 B.p.PC 138 102 102 30 149 132 - 39 156 106 49 - 42 187 214 97 83 97 102 49 -48 81 115 130 89 145 -64 229 131 146 121 - 27 66 111 74 113 151 87 156 162 46 48 90 75 CAS Registry No.71-41-0 107-87-9 96-22-0 109-67-1 628-63-7 638-49-3 76-19-7 80-56-8 110-89-4 123-38-6 74-98-6 57-55-6 504-63-2 71-23-8 67-63-0 107-12-1 109-60-4 107-10-8 1 15-07- 1 110-74-7 110-86- 1 109-97-7 123-75-1 100-42-5 2551-62-4 79-27-6 630-20-6 79-34-5 127-18-4 811-97-2 109-99-9 108-88-3 71-55-6 79-00-5 115-20-8 79-01-6 96-18-4 76-00-6 354-58-5 76- 13- 1 12 1-44-8 75-89-8 23.98 1.281 1 917 921 100.1 218 108-29-2 6.10 0.326 2 476 440 62.5 -14 75-01-4 7.24 0.387 2 511 515 97.0 32 75-35-4 22.62 1.211 0 869 871 106.2 138 108-38-3 23.32 1.250 0 892 895 106.2 144 95-47-6 22.66 1.213 0 870 870 106.2 138 106-42-31120 ANALYST, JULY 1992, VOL. 117 Table 3 Retention and relative detector response data on the SPB-1 column system (see legend to Fig.2 for chromatographic conditions)*-continued (b) Retention time order- Compound Methane Sulfur hexafluoride Acetylene Ethylene Nitrous oxide Ethane 1,1,1,2-Tetrafluoroethane Bromotrifluoromethane Formaldehyde Prop ylene Propane Chlorodifluoromethane Dichlorodifluoromethane Dimethyl ether 2-Chloro-l , 1-difluoroethane 2-Chloro-l , 1-difluoroethylene Acetaldehyde 1,2-Dichlorotetrafluoroethane Methanol Isobutane 2-Chloro-l,l,l-trifluoroethane But-1-ene Bromochlorodifluoromethane Butane Ethylene oxide Methyl formate Ethylamine 2,2-Dimethylpropane Bromomethane Monochloroethane Ethanol 2,2,2-Trifluoroethanol Acetonitrile Isoflurane Acetone Propanal Propan-2-01 Peffluoropropane Vinyl chloride Dibromodifluoromethane Fluorotrichloromethane Enflurane Cy anogen bromide Pent-1-ene Acrylonitrile Diethyl ether Pentane Ethyl formate Isoprene Methylal Methyl sulfide Iodomethane 2-Methylpropan-2-01 Vinylidine chloride 1,l-Dichloroethylene Methyl acetate Dichloromethane Prop ylamine l,l,l-Trichlorotrifluoroethane Nitromethane 1,1,2-Trichlorotrifluoroethane Carbon disulfide Cyclopropane 1-Chloropropane 2-Methylpropanal Propionitrile Propan-1-01 Halothane 1 ,ZDichloroethylene (both isomers) 2,2,3,3,4,4,4-Heptafluorobutan-l-o1 Diethylamine RT/ min 2.52 2.58 2.63 2.63 2.66 2.69 2.76 2.77 2.85 2.99 3.05 3.14 3.18 3.34 3.41 3.46 3.59 3.59 3.60 3.61 3.73 3.94 4.07 4.09 4.22 4.28 4.30 4.32 4.47 4.77 4.80 5.17 5.22 5.52 5.66 5.77 6.04 6.08 6.10 6.12 6.13 6.14 6.25 6.28 6.50 6.69 6.72 6.82 6.91 7.08 7.12 7.13 7.14 7.24 7.28 7.30 7.45 7.60 7.90 7.98 8.01 8.03 8.29 8.31 8.46 8.57 8.61 8.76 9.19 9.25 9.53 RRT 0.135 0.138 0.141 0.141 0.142 0.144 0.148 0.148 0.153 0.160 0.163 0.168 0.170 0.179 0.182 0.185 0.192 0.192 0.192 0.193 0.199 0.211 0.217 0.219 0.226 0.229 0.230 0.231 0.239 0.255 0.257 0.276 0.279 0.295 0.303 0.309 0.323 0.325 0.326 0.327 0.327 0.328 0.334 0.336 0.348 0.358 0.360 0.365 0.370 0.379 0.381 0.381 0.382 0.387 0.389 0.391 0.398 0.407 0.422 0.427 0.428 0.429 0.444 0.444 0.453 0.459 0.461 0.468 0.491 0.494 0.510 ECD 0 2 0 0 2 0 1 2 0 0 0 2 2 0 1 2 0 2 0 0 2 0 2 0 0 0 0 0 2 2 0 1 0 2 1 0 0 2 2 2 2 2 2 0 0 0 0 0 0 0 0 2 0 2 2 0 2 0 2 1 2 1 0 1 0 0 0 2 2 2 0ANALYST, JULY 1992, VOL.117 1121 Table 3 Retention and relative detector response data on the SPB-1 column system (see legend to Fig.2 for chromatographic conditions)*-continued (b) Retention time order- Compound Isopropyl formate 1,l-Dichloroethane Methyl tert-butyl ether Butane-2,3-dione 2-Methylpentane B utanal Butanone Isobutyl nitrite 3-Methylpentane 1,2-Epoxybutane Butan-2-01 Hex-1-ene Isobutylamine 1,3-Dioxolane Bromochloromethane Ethyl acetate Diisopropyl ether Hexane Iodoethane Chloroform Propyl formate 2-Meth ylpropan-1-01 1-Bromopropane Te trahydrofuran Methyl propionate 2-Methoxyethanol Butyl nitrite Nitroet hane 2-Methylbutan-2-01 1,2-Dichloroethane Meth ylcyclopentane 3-Methylbutanal l,l,l-Trichloroethane 2-Chloroethanol 1-Chlorobutane Methyl isopropyl ketone EthanolamineS Butan- 1-01 Isopropyl acetate Benzene Carbon tetrachloride Isopropyl nitrate Cyclohexane pent an-2-one Ethylene glycol$ Pyrrolidine 2-Nitropropane Pentane-2,3-dione Pen tanal Pentan-3-one Cyclohexene Dibromomethane Trieth ylamine 1,2-Dichloropropane Isopentyl nitrite (‘amyl nitrite’) 2-Methylhex-1-ene Bromodichloromethane Dioxane Hept-1-ene Trichloroet h ylene Isooctane 2-Ethoxyethanol l-Chloro-2,3-epoxypropane Ethyl propionate Isopentylamine 3-Methylpent-1-yn-3-01 Methyl methacrylate Propyl acetate 2,5-Dimethylfuran Chloral hydrate Heptane RT/ min 9.55 9.57 9.60 9.72 9.90 9.98 10.18 10.37 10.61 10.63 10.80 10.89 10.95 11.13 11.40 11.42 11.43 11.51 11.55 11.65 11.84 12.22 12.24 12.31 12.33 12.38 12.41 12.47 12.96 13.09 13.11 13.43 13.56 13.57 13.64 13.71 13.75 14.08 14.10 14.39 14.70 14.84 14.91 15.07 15.15 15.21 15.27 15.37 15.50 15.58 15.69 15.80 15.84 15.87 15.87 16.05 16.16 16.16 16.18 16.25 16.31 16.38 16.42 16.42 16.42 16.42 16.48 16.51 16.53 16.60 16.70 RRT 0.511 0.511 0.514 0.519 0.530 0.534 0.545 0.555 0.568 0.569 0.578 0.583 0.586 0.596 0.609 0.611 0.612 0.616 0.617 0.622 0.634 0.654 0.654 0.659 0.660 0.663 0.663 0.666 0.694 0.699 0.702 0.719 0.724 0.725 0.730 0.734 0.736 0.754 0.755 0.770 0.785 0.793 0.798 0.807 0.811 0.814 0.816 0.821 0.830 0.834 0.840 0.844 0.848 0.848 0.848 0.859 0.863 0.865 0.866 0.868 0.873 0.877 0.877 0.879 0.879 0.879 0.882 0.884 0.885 0.887 0.894 ECD 0 2 0 2 0 0 1 2 0 0 0 0 0 0 2 0 0 0 2 2 0 0 2 0 0 0 2 2 0 2 0 0 2 2 2 1 0 0 0 0 2 2 0 1 0 0 2 1 0 1 0 2 0 1 2 0 2 0 0 2 0 0 2 0 0 0 0 0 1 2 01122 ANALYST, JULY 1992, VOL.117 Table 3 Retention and relative detector response data on the SPB-1 column system (see legend to Fig. 2 for chromatographic conditions)*-continued (b) Retention time order- Compound 1,l-Difluorotetrachloroethane Methyl cyclopropyl ketone 1,2-DifluorotetrachIoroethane 1-Iodopropane Methyl butyrate I-Nitropropane Butyl formate Methoxyflurane Propane-1 ,2-diol$ 3-Meth ylbutan-l-ol 2-Methylpentan-2-01 1-Meth ylpyrrole Methyl isobutyl ketone 2-Mercaptoethanol 2-Methylbutan-1-01 Bromoacetonitrile Pyridine Methy lcyclohexane Pyrrole Methyl disulfide N, N-Dimethylformamide 1.1 ,2-Trichloroethane Pentan- 1-01 Piperidine Bromotrichloromethane Isobutyl acetate Toluene Pentane-2,4-dione 1,3-Dichloropropane Paraldehyde Hexan-3-one Hexan-2-one l-Bomo-2,3-epoxypropane Morpholine Hexanal Hexan-2-01 Dimethyl sulfoxide Oct-1-ene 1,2-Dibromoethane Propane-l,3-diol$ Butyl acetate Octane Furfural Pentyl formate Tetrachloroeth ylene 1-Iodobutane 4-Hydroxy-4-methylpentan-2-one N, N-Dimethylacetamide 1,1,1 ,ZTetrachloroethane Chlorobenzene Hexan- 1-01 Heptan-4-one 2,2 ,2-Trichloroethanol Allyl isothiocyanate Isopentyl acetate Ethylbenzene Oct-2-yne Allyl glycidyl ether 2,6-Dimethylpyridine Heptan-3-one rn-Xylene p-Xylene 4-Eth ylmorpholine 1,3-Dichloropropan-2-ol C yclohexanol Heptan-2-one Bromoform 2-Ethoxyethyl acetate Cyclohexanone Heptanal Styrene RTI min 16.77 16.85 16.90 16.90 16.94 17.00 17.02 17.04 17.09 17.45 17.45 17.56 17.60 17.63 17.63 17.65 17.65 17.82 17.97 18.07 18.47 18.72 18.74 18.81 18.98 19.00 19.14 19.17 19.20 19.28 19.33 19.45 19.54 19.77 19.82 19.95 19.97 20.17 20.20 20.29 20.36 20.57 20.74 20.87 20.89 20.91 21.17 21.61 21.85 21.90 22.12 22.27 22.29 22.31 22.34 22.38 22.57 22.62 22.62 22.62 22.62 22.66 22.68 22.74 22.77 22.79 22.82 22.83 22.90 23.05 23.18 RRT 0.896 0.902 0.903 0.903 0.907 0.907 0.911 0.910 0.915 0.934 0.934 0.940 0.942 0.942 0.944 0.943 0.945 0.954 0.962 0.965 0.989 1 .Ooo 1.003 1.007 1.014 1.017 1.025 1.026 1.026 1.032 1.035 1.041 1.044 1.056 1.061 1.068 1.069 1.080 1.079 1.086 1.090 1.101 1.108 1.117 1.116 1.117 1.131 1.157 1.167 1.170 1.184 1.192 1.191 1.192 1.196 1.198 1.208 1.211 1.211 1.211 1.211 1.213 1.214 1.215 1.219 1.220 1.219 1.222 1.226 1.234 1.241 ECD 2 0 2 2 0 2 0 2 0 0 0 0 1 1 0 2 0 0 0 1 0 2 0 1 2 0 0 0 2 0 0 0 2 1 0 0 0 0 2 0 0 0 1 0 2 2 1 0 2 1 0 0 2 2 0 0 0 0 0 0 0 0 0 2 0 0 2 0 1 0 0ANALYST, JULY 1992, VOL.117 1123 Table 3 Retention and relative detector response data on the SPB-1 column system (see legend to Fig. 2 for chromatographic conditions) *-continued (b) Retention time order- Compound Hexane-2,5-dione Pentyl acetate o-Xylene 1,1,2,2-Tetrachloroethane 1,2,3-Trichloropropane Nonane Hexyl formate 1,l ,l-Trichloropropan-2-ol y-Valerolactone Cumene Bromobenzene Benzaldehyde a-Pinene Heptan-1-01 1-Chloro-2-methylbenzene Octan-4-one 1-Chloro-3-methylbenzene 1-Chloro-4-methylbenzene Benzonitrile 6-Methylhept-5-ene-2-one Octan-3-one Octan-Zone Chlorobutanol Bicyclo[4.3.0]nonane Methyl hexanoate 1,1,2,2-Tetrabromoethane Octan-2-01 Limonene Octanal 2-Chlorophenol Hexyl acetate RT/ min 23.25 23.31 23.32 23.33 23.53 23.56 23.84 23.85 23.98 24.19 24.45 24.75 24.81 24.88 24.96 24.99 25.03 25.05 25.16 25.24 25.29 25.39 25.44 25.48 25.50 25.50 25.65 25.69 25.70 25.83 25.83 RRT 1.242 1.248 1.250 1.246 1.257 1.261 1.276 1.274 1.281 1.295 1.306 1.325 1.328 1.332 1.336 1.338 1.337 1.343 1.347 1.351 1.354 1.359 1.359 1.364 1.365 1.362 1.373 1.375 1.376 1.380 1.383 ECD 1 0 0 2 2 0 0 2 1 0 2 0 0 0 1 0 1 1 0 0 0 0 2 0 0 2 0 0 0 2 0 * RT = retention time; RRT = retention time relative to 1,1,2-trichloroethane (on the ECD channel for compounds responding on that channel); ECD = relative ECD response (0 = nil, 1 = poor, 2 = good); Retention index = KovAts retention index (Calc.= calculated on the SPB-1 system, Lit. = literature value on SE-30,OV-1 or OV-lOl;3JOB.p.= boiling-point at atmospheric pressure; CAS Registry No. = Chemical Abstracts Service Registry Number. t B.p. at 24 mmHg. $ Compounds injected as liquids. Fig. 3. All of the homologues gave straight-line plots with gradients identical with that given (by definition) by the n-alkanes. Homologues of secondary alcohols and methyl ketones gave results virtually identical with those of the aldehydes, chloride homologues to the primary alcohols and iodide homologues to the acetates studied, respectively. These results provide evidence of the reliability of the data generated with the temperature programme on the SPB-1 column. The retention indices for higher molecular mass compounds (retention indices in the range 1000-3300) have been com- pared on dimethylpolysiloxane-coated packed and capillary columns. Japp et aZ.11 studied 75 compounds and reported good correlations ( r = 0.995 or better) between packed column data and those obtained on capillary columns with inside diameters up to 0.53 mm, but did not comment on any systematic bias.In contrast, bra-Tamayo ef aZ.12 reported that in 88 out of 103 instances the retention index was longer on the 0.2 mm i.d. capillary column used. Others have discussed the reproducibiIity of retention data on dimethyl- polysiloxane-coated capillaries and have reported variations in retention time with amount of analyte injected,13 but this is probably attributable to overloading of the relatively narrow- bore, low film thickness capillaries used. The retention indices measured on the SPB-1 capillary are plotted against the packed column retention indices [Table 3(a)] in Fig.4. Although there was a good correlation between the two sets of data ( r = 0.983, n = 165), linear regression analysis gave an intercept of +42.2 retention index units on the ordinate (packed column data). The difference in the retention indices on the two systems (RIspB-l - RIpacked) is plotted against the retention indices on the SPB-1 column in Fig. 5. Clearly there is a tendency for the retention index to be longer on the packed column across the range of compounds studied. It is possible that either polar interactions with the support in the packed column or difficulties in measuring the retention of very volatile compounds on packed columns are responsible for this finding.Application to Sample Analyses The sample preparation procedure was that of Ramsey and Flanagan3 except that 0.20 rather than 0.10 cm3 of internal standard solution were used and it was not necessary to use nitrogen-filled vials. A typical ‘reagent blank’ analysis is illustrated in Fig. 6. Apart from the internal standards the only identifiable compounds were small amounts of methanol, which may have originated from the laboratory atmosphere, and chloroform, which probably arose from chlorination of the public water supply used to feed the laboratory de-ionizer. The analysis of a blood specimen from an adolescent who died after abusing ‘butane’ gas and vapour from a typewriter correcting fluid is shown in Fig. 7. The analysis of a blood specimen from a patient who died after inhaling vapour from an electrical component cleaner is illustrated in Fig.8. I t . is clear that the concentrations of the components of interest1124 Chloroform ANALYST, JULY 1992, VOL. 117 100 1 Table 4 Inter-assay reproducibility data (n = 30 in each instance) (GC conditions as in Fig. 2) Retention Relative Compound Propane FC 12 Dimethyl ether Isobutane BCF Butane Ethanol Acetone Propan-2-01 FC 11 FC 113 Halothane Butanone Hexane Chloroform l,l,l-Trichloroethane Carbon tetrachloride Trichloroethylene Methyl isobutyl ketone 1,1,2-Trichloroethane Toluene Tetrachloroethylene 2,2 ,2-Trichloroethanol Et h y lbenzene time/ min 3.050 3.179 3.338 3.613 4.065 4.091 4.795 5.664 6.036 6.128 8.013 8.763 10.173 11.512 11.651 13.559 14.703 16.245 17.602 18.720 19.143 20.892 22.292 22.377 retention RSD (%) time 0.27 0.67 0.25 0.24 0.90 0.23 0.23 0.20 0.23 0.71 0.51 0.19 0.14 0.11 0.19 0.14 0.12 0.09 0.06 0.06 0.05 0.05 0.07 0.04 0.163 0.170 0.179 0.193 0.217 0.219 0.257 0.303 0.323 0.327 0.428 0.468 0.545 0.616 0.622 0.724 0.785 0.868 0.942 1.OOO 1.025 1.116 1.191 1.198 RSD (Yo) 0.32 0.64 0.28 0.29 0.89 0.19 0.25 0.20 0.20 0.67 0.49 0.13 0.12 0.08 0.15 0.09 0.09 0.05 0.04 co.01 0.04 0.08 co.01 - 1000 800 X 7 600 .- C 0 $ 400 a .- +a a 200 0 1 2 3 4 5 6 7 8 9 No.of carbon atoms Fig. 3 Kovdts retention indices measured using the temperature programme on the SPB-1 column of homologous series: A, acetates; B, formates; C, alcohols; D, aldehydes; and E, alk-1-enes plotted against number of carbon atoms (cf., Table 3) 1200 1000 800 0 Y m P ct 600 400 8 I I 1 200 400 600 800 1000 RkP6-7 Fig.4 KovAts retention indices of compounds measured using the temperature programme on the SPB-1 column plotted against literature values on SE-30/OV-l/OV-101 oacked columns ( r = 0.983. I a 8 8 I -200 I I I I 200 400 600 800 1000 RkPB-1 Fig. 5 Plot of the difference in the Kovdts retention indices on the SPB-1 and packed columns against retention index on the SPB-1 column (cf., Fig. 4) t ln 0 P 2 0 L t ln 0 P 2 n u w Ethyl benzene (4 Methanol t I. P J I 1 1 I I 1,1,2-Trichloro. ethane I I 1 I I 0 5 10 15 20 25 Timelmi n Fig. 6 Analysis of the internal standard solution (GC conditions as in Fig. 2): sample volume, 0.20 cm3; injection volume, 0.30 cm3 headspace; and detector sensitivities (FSD): (a) FID 80 pA and (b) ECD 2 kHz were well above the limit of detection of the system.Indeed, although no formal studies have been performed, the sensitiv- ity attainable appears to be similar to that obtained using an FID-ECD splitting ratio of 10 : 1 with the modified Carbopack packed column system, i.e., of the order of 0.01 mg dm-3 for ECD-responding compounds and 0.1 mg dm-3 for the remainder.3 Hence sensitivity enhancement either by 'salting- out' or the use of purge-and-trap devices is unnecessary when working with clinical or forensic specimens. The compounds studied included those listed in Table 1 and other common halons, solvents and metabolites and products of putrefaction such as methyl sulfide. Of the commonly encountered compounds only isobutane-methanol and tolu- ene-paraldehyde are at all difficult to resolve.If paraldehyde is suspected the addition of 6 mol dm-3 sulfuric acid (0.20 cm3) to the vial followed by reincubation should remove the paraldehyde peak and lead to an increase in the acetaldehyde n = 165; cf., Table 3). Solid line: y = x ' peak. Measirement of released acetaldehyde has bkenANALYST, JULY 1992, VOL. 117 1125 t v) 0 P E 0 LL t v) 0 9. E n u w :a) sobutan ’ropane 4 3utane Ethylbenzene 1 I- 1,1,2-Trichloro- ethane 1,1,1 -Tric hloro- ethane 0 5 10 15 20 25 Ti me/m i n Fig. 7 Analysis of a whole blood specimen (0.20 cm3) from a patient who died after abusing cigarette lighter refills and a typewriter correcting fluid containing 1,l ,l-trichloroethane (GC conditions as in Fig.2): injection volume, 0.30 cm3 headspace; detector sensitivities (FSD): (a) FID 80 pA and (b) ECD 2 kHz; whole blood l,l,l- trichloroethane concentration 1.2 mg dm-3 advocated for metaldehyde assay in biological specimens,14 although this approach has not proved successful in our hands. Isobutane is unlikely to be found in the complete absence of butane and propane (cf., Table 1). Methanol is rapidly oxidized in aqueous solution on mixing with potassium dichromate (5% d v ) in dilute sulfuric acid (6 mol dm-3). Methanol cannot be directly removed from blood in this way but can be oxidized after headspace transfer to a second, warmed vial before adding the dichromate reagent. However, such transfer may be associated with a considerable decrease in sensitivity.Other workers using packed columns have emphasized the need to use retention data from two different columns before reporting results.9.15 However, as in any toxicological investi- gation the results must never be considered in isolation from any clinical or circumstantial evidence. In addition, the use of an efficient capillary column together with two different detectors confers a high degree of selectivity, particularly for low formula mass compounds where there are very few alternative structures. If more rigorous identification is required, GC combined with mass spectrometry (MS) or Fourier transform infrared (FTIR) spectrometry may be used. However, GC-MS can be difficult when the fragments produced are of less than mlz 40, particularly if the instrument is also used for purposes other than solvent analyses.In t v) 0 a 2 0 LL t v) 0 P 2 n E [a) Ethyl benzene b) FC 12 FC 11 I, 1,1.2-Trichloroethane ; 113 1- I I 1 1 0 5 10 15 20 25 Time/m i n Fig. 8 Analysis of a whole blood specimen (0.20 cm3) from a patient who died after abusing an aerosol designed for cleaning electrical components and which contained FCs 11,12, and 113 (GC conditions as in Fig. 2): injection volume 0.15 cm3 headspace; detector sensitivities (FSD): (a) FID 160 pA and (b) ECD 4 kHz; whole blood FC 11 and 113 concentrations 3.2 and 1.0 mg dm-3, respectively particular, the available sensitivity and spectra of the low molecular mass alkanes renders them very difficult to confirm by GC-MS. Gas chromatography-FTIR is more appropriate to the analysis of volatiles, but the sensitivity is relatively poor particularly when compared.with ECD.In addition, interfer- ences, particularly from water and carbon dioxide in biological specimens, can be troublesome. The likelihood of detecting exposure to volatile substances by headspace GC of blood is influenced by the nature of the compound(s) involved, the extent and duration of exposure, the time of sampling in relation to the time elapsed since exposure and the precautions taken when collecting and storing the sample.2 In one series of suspected abusers, volatile compounds or metabolites were detected in 79 out of 125 cases.16 In 69 (87%) of the positive cases the samples were obtained within 10 h of the suspected exposure. Nevertheless, exposure can be detected using later samples.Thus, in separate cases toluene was detected at 40 h and 2,2,2- trichloroethanol (from trichloroethylene) at 48 h. 16 Analysis of urinary metabolites may extend the time in which exposure may be detected but, of the compounds commonly abused, only toluene, the xylenes and some chlorinated solvents, notably trichloroethylene, have suitable metabolites.2 On the other hand, direct MS of expired air can detect many compounds several days post-exposure. However, the use of this technique is limited by the need to take breath directly from the patient. Chronic petrol ‘sniffing’ has been diagnosed by the measurement of blood lead concentrations17 or the detection of aromatic components such as toluene.18 However, with some petrols and with other complex mixtures such as light petroleums (Table 1) the blood concentrations of the indivi- dual components may be below the limit of detection of the method even after massive exposure.This is illustrated by the1126 ANALYST, JULY 1992, VOL. 117 analysis of blood after human exposure to the petroleum distillate white spirit (British Standard 245 : 1976) (boiling- point range 150-200 "C distributed around nonane) at a concentration of 577 mg m-3 for 4 h. Blood total hydrocarbons (initially about 1.5 mg dm-3) were measurable for only 0.3 h post-exposure (limit of detection 0.5 mg dm-3). However, after similar exposure (520 mg m-3, 3.3 h) to nonane alone, nonane excretion could be followed for at least 3 h.193 In both instances the headspace vial was incubated at 80 "C to maximize the amount of analyte volatilized.The lower sensitivity for white spirit was attributed to the distribution of the hydrocarbon load among many peaks rather than the single peak given by nonane. Most volatile compounds are relatively stable in blood if simple precautions are taken. The container should be glass, preferably with a cap lined with metal foil; greater losses may occur if plastic containers are used. The tube should be as full as possible and, ideally, should only be opened when required for analysis and then only when cold (4 OC).6 If the sample volume is limited it is advisable to select the container to match the volume of blood so that there is minimal headspace. An anticoagulant (lithium heparin or ethylenediaminetetra- acetic acid) should be used.Specimen storage between -5 and 4 "C is recommended and, for esters such as ethyl and methyl acetates, addition of 1% m/v of sodium fluoride is advisable to minimize esterase activity. However, many samples submitted in far from ideal circumstances still give useful qualitative results. It is vital that any products thought to have been abused are packed and stored separately from biological specimens to avoid cross-contamination. In a suspected VSA fatality, analysis of tissues (especially fatty tissues such as brain) may prove useful as high concentrations of volatile compounds may be found even if very little is detectable in blood. Tissue specimens should be stored before analysis in the same way as blood. Detection of a volatile compound in blood does not always indicate VSA or occupational/environmental exposure to solvent vapour.Acetone and some homologues may occur in high concentrations in ketotic patients. Large amounts of acetone and butanone may also occur in blood and urine from children with acetoacetyl CoA thiolase deficiency and may indicate the diagnosis.21 Acetone is also the major metabolite of exogenous propan-2-01 in man .223 Conversely, propan-2- 01 has recently been found in blood from ketotic ~atients.2~ Other ketones may give rise to alcohols in vivo. For example, cyclohexanol is the principal metabolite of cyclohexanone in man.25 A further complication is that contamination of the sample with ethanol or propan-2-01 may occur if an alcohol- soaked swab is used to cleanse skin prior to venepuncture.Other volatile compounds such as halothane and paraldehyde may be used in therapy, and chlorobutanol (chlorbutol), a sedative which is also used as a bacteriocide in some mucous heparin preparations, for example, may also occur. Small amounts of hexanal may arise from degradation of fatty acids in blood on long-term storage, even after storage at -5 to -20 "C.6 Hexanal is resolved from toluene using the temperature- programmed system described above but resolution may be lost if an isothermal quantitative analysis is performed. However, interference from hexanal is only likely to be important if very low concentrations of toluene (0.1 rng dm-3 or less) are to be measured. On the other hand, massive interference from ethylbenzene, rn-lp-xylene and o-xylene has been encountered in samples collected into Sarstedt Mono- vitte Serum Gel blood tubes.Information on the composition of commonly abused products has been given previously.2 When interpreting the results of qualitative analyses it is important to remember that some compounds usually occur in association one with another (Table 5). Blood toluene concentrations in samples from 132 VSA patients ranged from 0.2 to 70 mg dm-3 and were above 5 mg dm-3 in 22 of the 25 deaths.16 Blood Table 5 Associated compounds Compound Acetone BCF Butane Cyclohexanone Dimethyl ether Ethyl acetate* FC 11 FC 12 FC 22 Halothane Isobutane Methyl acetate* Propane Propan-2-01 1,l , 1-Trichloroethane 2,2.2-Trichloroethanol Trichloroe thylene Common associated compound(s) ketoacidosis, propan-2-01 (metabolite, rare) Butanone and higher ketones in FC 11 Butan-1-01, butan-2-01, butanone Cyclohexanol (metabolite) FC 22 Ethanol (metabolite) BCF, FC 12 FC 11 Dimethyl ether 2-Chloro-l,l-difluoroethylene, (metabolites, rare), isobutane, propane 2-chloro-1 ,l,l-trifluoroethane (metabolites, rare) Butane, propane Methanol (metabolite) Butane, isobutane Acetone (metabolite) Isopropyl nitrate (stabilizer, rare) Trichloroethylene (also metabolite of chloral hydrate , dichloralphenazone and trichlofos) 2,2,2-Trichloroethanol (metabolite), chloroform [possibly from thermal degradation of trichloroacetic acid (metabolite) in vitro] * Parent compounds not normally detected in blood.l,l,l-trichloroethane concentrations ranged from 0.1 to 60 mg dm-3 in samples from 66 VSA patients, 29 of whom died.16 However, the possibility of loss of analyte from the sample prior to the analysis must always be considered, especially with very volatile analytes such as butane.Indeed, the difficulty in ensuring that unacceptable losses do not occur during sample collection, transport and storage is the major reason why measurement of such compounds is not often justified. Conclusions The 60 m SPB-1 column has been found to be a valuable alternative to packed columns in the headspace GC analysis of specimens from patients suspected of VSA. Most commonly abused compounds, including many with very low boiling- points such as BCF, butane, dimethyl ether, FC 11, FC 12, isobutane and propane, can be retained and differentiated at an initial column temperature of 40 "C followed by program- ming to 200 "C.The total analysis time is only 26 min. Good peak shapes are obtained for polar analytes such as ethanol and on-column injections of up to 0.30 cm3 of headspace can be performed with no discernable loss of efficiency. The sensitivity is thus at least as good as that attainable with packed columns. Of the commonly occurring compounds only isobutane-methanol and paraldehyde-toluene are at all diffi- cult to differentiate. Quantitative analyses can be performed by using appropriate calibration standards. We thank Supelchem UK for the gift of the SPB-1 column, the British Aerosol Manufacturer's Association , Re-Solv and ICI Pharmaceuticals for financial support and Abbott Labora- tories, C-VET, the Health and Safety Executive Laboratories, Cricklewood, and Rh6ne-Poulenc for gifts of pure com- pounds. References 1 Wright, S. P., Pottier, A. C. W., Taylor, J. C., Norman, C. L., Anderson, H. R., and Ramsey, J. D., Trends in DeathsANALYST, JULY 1992, VOL. 117 1127 2 3 4 5 6 7 8 9 10 11 12 13 14 Associated with Abuse of Volatile Substances 1971-1989, St. George’s Hospital Medical School, London, 1990. Flanagan, R. J., Ruprah, M., Meredith, T. J., and Ramsey, J. D., Drug Safety, 1990, 5 , 359. Ramsey, J. D., and Flanagan, R. J., J. Chromatogr., 1982,240, 423. van den Dool, H., and Kratz, P. D., J. Chromatogr., 1963, 11, 463. Lee, J., and Taylor, D. R., Chromatographia, 1983, 16, 286. Gill, R., Hatchett, S. E., Osselton, M. D., Wilson, H. K., and Ramsey, J. D., J. Anal. Toxicol., 1988, 12, 141. Gill, R., Hatchett, S. E., Warner, H. E., Osselton, M. D., Wilson, H. K., Wilcox, A. H., and Ramsey, J. D., in Proceedings of the Meeting of the International Association of Forensic Toxicologists, Glasgow, August 1989, Aberdeen Uni- versity Press, Aberdeen, in the press. Pekari, K., Riekkola, M.-L., and Aitio, A., J. Chromatogr., 1989,491, 309. Franke, J. P., Wijsbeek, J., de Zeeuw, R. A., Moller, M. R., and Niermeyer, H., J. Anal. Toxicol., 1988, 12,20. Ardrey, R. E., de Zeeuw, R. A., Finkle, B. S., Franke, J. P., Moffat, A. C., Moller, M. R., and Muller, R. K., Gas- chromatographic Retention Indices of Toxicologically Relevant Substances on SE-30or OV-1, VCH, Weinheim, 2nd edn., 1985. Japp, M., Gill, R., and Osselton, M. D., J. Forensic Sci., 1987, 32, 1574. Lora-Tamayo, C., Rams, M. A,, and Chacon, J. M. R., J. Chromatogr., 1986, 374, 73. Bogusz, M., Wijsbeek, J., Franke, J. P., and de Zeeuw, R. A., J. Anal. Toxicol., 1983, 7, 188. Griffiths, C. J., J. 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Kawai, T., Yasugi, T., Horiguchi, S., Uchida, Y., Iwami, O., Iguchi, H., Inoue, O., Watanabe, T., Nakatsuka, H., and Ikeda, M., Int. Arch. Occup. Environ. Health, 1990, 62, 409. Bailey, D. N., Clin. Toxicol., 1990, 28, 459. Sakata, M., Kikuchi, J., Haga, M., Ishiyama, N., Maeda, T., Ise, T., and Hikita, N., Clin. Toxicol., 1989, 27, 67. Paper 2/00450J Received January 28, 1992 Accepted February 14, 1992