Drugs and Poisons in Humans - A Handbook of Practical Analysis (Part 69)

8.4II.8.4 Arsenic compounds and other inorganic poisonsby Sinichi Suzuki and Yasuhiro SuzukiIntroductionThe Wakayama Curry Poisoning Incident taking place in August 1998, followed by various imitative poisoning incidents, is still fresh in our memory, because they gave a severe shock and anxiety to the Japanese society. The poison, which had been used in the Wakayama Curry Poisoning Incident was an arsenitea, a classical poison. However, since the acute poisoning case by an arsenite is rare nowadays, it took some time to identify the compound, and caused confusion at the initial step of criminal investigation. Diarsenic trioxide (As2O3, arsenic (III) oxide) is...
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Drugs and Poisons in Humans - A Handbook of Practical Analysis (Part 69) 8.4II.8.4 Arsenic compounds and other inorganic poisons by Sinichi Suzuki and Yasuhiro SuzukiIntroductionThe Wakayama Curry Poisoning Incident taking place in August 1998, followed by variousimitative poisoning incidents, is still fresh in our memory, because they gave a severe shockand anxiety to the Japanese society. The poison, which had been used in the Wakayama CurryPoisoning Incident was an arsenitea, a classical poison. However, since the acute poisoning caseby an arsenite is rare nowadays, it took some time to identify the compound, and caused confu-sion at the initial step of criminal investigation. Diarsenic trioxide (As2O3, arsenic (III) oxide) is a trivalent arsenic compound and thushighly toxic, in contrast to less toxic pentavalent arsenates b being widely distributed in nature.When diarsenic trioxide is dissolved in water, it is immediately converted into the arseniousacidc, which actually exerts its toxicity in humans. The oral LD50 value of diarsenic trioxide inhumans is said to be 60–120 mg. As other inorganic poisons, cadmium, thallium, lead, chro-mium and copper can be mentioned; however they and their derivatives are much less toxicthan arsenious acid. These inorganic compounds can be analyzed by the similar methodsto those for arsenic compounds. In this chapter, analytical methods for arsenic compoundstogether with other inorganic poisons are described.ReagentsDiarsenic trioxide and dimethylarsinic acid (DMAA) can be purchased from Sigma (St. Louis,MO, USA) and other manufacturers. Nitric acid and hydrochloric acid should be of ultra puregrade usable for inductively coupled plasma mass spectrometry (ICP-MS). Other reagents areof special grade.Instrumental conditionsi. X-ray fluorescence analysisInstrument: a PW1404 type X-ray fluorescence analysis instrument (Philips, Almelo, Nether-lands). Analytical conditions; X-ray tube: target Rh; operating voltage: 50 kV; operating current:50 mA; crystal: LiF; detectors: scintillation counter and gas flow proportional counter.© Springer-Verlag Berlin Heidelberg 2005638 Arsenic compounds and other inorganic poisons ii. Ion chromatography (IC) analysis Instrument: a DX-500 type ion chromatograph equipped with an autosuppressor (Dionex, Sunnyvale, CA, USA). Analytical conditions; separation column: IonPac AS10 (25 cm × 2 mm i. d., particle size 8.5 µm); guard column: IonPac AC10 (both from Dionex); mobile phase: 75 mM NaOH solu- tion (1-min hold) is subjected to linear gradient up to 150 mM NaOH solution during 7 min; its flow rate: 1.3 mL/min; detectors: conductivity and electrochemical detectors (ECD). iii. Inductively couple plasma atomic emission spectrometry (ICP-AES) Instrument: an SPS-1700 HVR ICP-AES instrument (Seiko Instruments, Chiba, Japan). Analytical conditions; high-frequency output: 1.3 kW; plasma gas: argon (16 L/min); assisting gas: argon (0.5 L/min); carrier gas: argon (1.0 L/min); sample flow rate: 0.5 mL/min. iv. Inductively couple plasma mass spectrometry (ICP-MS) Instrument: an SPQ 8000 type ICP-MS instrument (Seiko Instruments). Analytical conditions; high-frequency output: 1.2 kW; plasma gas: argon (16 L/min); assisting gas (flow rate): argon (0.75 L/min); carrier gas (flow rate): argon (0.45 L/min); sampling posi- tion: 13 mm. v. Ion chromatography/inductively coupled plasma mass spectrometry (IC/ICP-MS) Instrument HPIC 7000-HP 4500 type IC/ICP-MS (Agilent Technologies, Palo Alto, CA, USA). IC conditions; column: anion type IC-A15 (150 × 4.6 mm i.d., Hitachi Chemical, Tokyo, Japan); guard column: IC-A15G (Hitachi Chemical); mobile phase: 0.2 mM EDTA/2.0 mM sodium phosphate buffer solution (pH 6.0); flow rate: 1.0 mL/min; column temperature: room temperature. ICP-MS conditions; high-frequency output: 1.4 kW; plasma gas: argon (1.5 L/min); assist- ing gas: argon (1.0 L/min); carrier gas (flow rate): argon (1.1 L/min); arsenic detection mass number: m/z 75. Procedures i. Foods and vomitus i. A method to be chosen first is the X-ray fluorescence analysis, which is non-invasive and thus does not destroy a specimen. It gives informations on elements included in a speci- men, but cannot discriminate the forms of molecules containing such elements (for exam- ple, trivalent or pentavalent). The X-ray fluorescence analysis should be performed, when the presence of an inorganic poison is suspected, after analysis of organic compounds. > Fig- ure 4.1 shows an X-ray fluorescence spectrum for a food specimen cont ...