Drugs and Poisons in Humans - A Handbook of Practical Analysis (Part 16)

Introduction:Toluene, benzene, xylene and styrene are being widely used for chemical product materials, solvents and constituents of adhesives and paints, and thus sometimes cause poisoning incidents by inhaling their gas at chemical product-manufacturing factories. The abuse of thinner solvents, containing toluene, benzene and xylene, is now a social problem especially for young people. There are many crimes and poisoning incidents involving the thinner solvent abuse. Recently, styrene leaking from new building materials is an object of interest, because it causes the sick house syndrome. The above four solvents are rapidly absorbed into human body by inhalation, per os and...
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Drugs and Poisons in Humans - A Handbook of Practical Analysis (Part 16) 1.7II.1.7 Toluene, benzene, xylene and styrene by Xiao-Pen Lee and Keizo SatoIntroductionToluene, benzene, xylene and styrene are being widely used for chemical product materials,solvents and constituents of adhesives and paints, and thus sometimes cause poisoning inci-dents by inhaling their gas at chemical product-manufacturing factories. The abuse of thinnersolvents, containing toluene, benzene and xylene, is now a social problem especially for youngpeople. There are many crimes and poisoning incidents involving the thinner solvent abuse.Recently, styrene leaking from new building materials is an object of interest, because it causesthe sick house syndrome. The above four solvents are rapidly absorbed into human body by inhalation, per osand percutaneously to cause various disturbances, such as suppression of the central nervoussystem. In addition, benzene and styrene are being regarded as carcinogenic compounds. For analysis of toluene, benzene, xylene and styrene, the conventional GC methods withpacked columns are being used [1–10]. In this chapter, a method of their analysis for humanblood using headspace wide-bore capillary GC is presented.Reagents and their preparation• Standard solutions: toluene, benzene or each isomer a of xylene of special grade is dissolved in methanol to prepare each 1 mg/mL solution.• Internal standard (IS) solution: aniline of special grade is dissolved in methanol to give 10 mg/mL solution.GC conditionsColumn: an Rtx-BAC2 wide-bore capillary column (30 m × 0.53 mm i. d., film thickness2.0 µm, Restek, Bellefonte, PA, USA). GC conditions; instrument: a Shimazu GC-14B gas chromatograph (Shimadzu Corp.,Kyoto, Japan); detector: FID; column (oven) temperature: 30 °C (1 min) → 15 °C/min → 240 °Cinjection and detector temperature: 240 °C; carrier gas: He; its flow rate: 5.0 mL/min.© Springer-Verlag Berlin Heidelberg 2005150 Toluene, benzene, xylene and styrene Procedure i. A 0.5 mL volume of whole blood, 20 µL (200 µg) of IS solution, 1.5 mL of distilled water and 0.6 g of solid NaCl b are placed in a 7.5 mL volume vial, stoppered with a silicone-sep- tum cap and mixed well. ii. The vial is heated at 100 °C with stirringc on an aluminum block heater. After 15 min of heating, about 0.6 mL of the headspace vapor is drawn into a gas-tight syringed and the volume of the vapor is reduced to 0.3 mLe by pushing the plunger. It is immediately in- jected into GC for analysis. iii. Quantitation: to each 0.5 mL of blank whole blood, one of the known amounts of each solvent and 200 µg of IS are added to construct a calibration curvef, consisting of concen- tration of a solvent on the horizontal axis and peak area ratio of a solvent to IS on the verti- cal axis for enabling calculation of a concentration of a test compound in whole blood. Assessment of the method > Figure 7.1 shows a headspace wide-bore capillary gas chromatogram obtained from 0.5 mL whole blood, to which toluene, benzene, 3 kinds of xylene isomers and styrene, 3 µL (3 µg) of each, together with 20 µL (200 µg) of IS solution, had been added. Every peak was separated well from each other except for m- and p-xylenes. The background was clean with few impu- rity peaks. The extraction efficiencies (recoveries) for each organic solvent are 3.1–5.2 %. Good linearity of the calibration curve can be obtained in the range of 0.5–5.0 µg/0.5 mL for each compound; the detection limit is equally about 0.2 µg/0.5 mL. It is impossible to separate m-xylene from p-xylene with the present Rtx-BAC2 wide-bore capillary column. To separate such isomers, the use of a packed column with Bentone-34 or a chiral capillary column, such as an α-DEX 120 capillary column (Supelco, Bellefonte, PA, USA), is recommendable. Toxic and fatal concentrations and poisoning symptoms Although the poisoning effects of toluene and benzene vary according to different individuals, the oral ingestion of 15–20 mL toluene generally causes serious toxicity. The fatal dose of ben- zene is estimated to be about 100 mL; but there was a case in which a subject died after oral in- gestion of only 15 mL benzene. The atmospheric concentration of toluene at 2,000 ppm is dan- gerous for humans [11]. There is a possibility of death after single inhalation of 10,000 ppm gas of benzene [11]. The maximum permissible atmospheric concentrations of toluene and benzene are 50 and 0.5 ppm, respectively, according to the Japanese Society of Industrial Hygiene. In fa ...