tailieunhanh - Drugs and Poisons in Humans - A Handbook of Practical Analysis (Part 10)

Introduction: The incidence of carbon monoxide (CO) poisoning is highest among those of various poisonings in forensic science practice; about 2/3 of the total accidental poisoning deaths is due to CO poisoning in Japan [1]. Previously, suicides, homicides and accidental deaths frequently took place using city gas containing about 9% CO. However, during recent years, city gas is being replaced by natural gas containing no CO, resulting in drastic decrease of the number of CO poisoning cases. Nevertheless, many incidents of CO poisoning are occurring due to imperfect combustion, fire, exhaust gas of automobiles and other causes. For a victim. | II. Chapters on specific toxins Carbon monoxide By Keizo Sato Introduction The incidence of carbon monoxide CO poisoning is highest among those of various poisonings in forensic science practice about 2 3 of the total accidental poisoning deaths is due to CO poisoning in Japan 1 . Previously suicides homicides and accidental deaths frequently took place using city gas containing about 9 CO. However during recent years city gas is being replaced by natural gas containing no CO resulting in drastic decrease of the number of CO poisoning cases. Nevertheless many incidents of CO poisoning are occurring due to imperfect combustion fire exhaust gas of automobiles and other causes. For a victim found at the scene of a fire the saturation ratio of carboxyhemoglobin COHb can be an indicator for judging whether the victim has died in a fire or had been already killed before the fire. For measurements of COHb saturation ratios in blood spectrophotometric and GC methods are available. Since methemoglobin Met-Hb is contained in many of blood specimens in forensic science practice for measurements of COHb saturation 2 it is important to use a methodb which is not influenced by the presence of Met-Hb. In this chapter simple and reliable spectrophotometric 3 and GC 4 methods for measurements of COHb saturation not to be influenced by Met-Hb are presented. Spectrophotometric method See 3 . Reagents and their preparation Na2CO3 solution g Na2CO3 is dissolved in distilled water to prepare 100 mL solution. 5 M NaOH solution 20 g NaOH is dissolved in distilled water to prepare 100 mL solution. Sodium hydrosulfite sodium dithionite obtainable from Yoneyama Yakuhin Kogyo Co. Osaka and other manufacturers. Analytical instrument A Hitachi 557 dual-wavelength spectrophotometer Hitachi Ltd. Tokyo Japan Springer-Verlag Berlin Heidelberg 2005 92 Carbon monoxide Procedure i. Two 3-ml volume cuvettes of the same type are cleaned well by washing with distilled water. ii. A .