Arsenic compounds and other inorganic poisons by Sinichi Suzuki and Yasuhiro Suzuki Introduction The 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. | Arsenic compounds and other inorganic poisons by Sinichi Suzuki and Yasuhiro Suzuki Introduction The 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 arsenite 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 a trivalent arsenic compound and thus highly 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 arsenious acidc which actually exerts its toxicity in humans. The oral LD50 value of diarsenic trioxide in humans is said to be 60-120 mg. As other inorganic poisons cadmium thallium lead chromium and copper can be mentioned however they and their derivatives are much less toxic than arsenious acid. These inorganic compounds can be analyzed by the similar methods to those for arsenic compounds. In this chapter analytical methods for arsenic compounds together with other inorganic poisons are described. Reagents Diarsenic 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 pure grade usable for inductively coupled plasma mass spectrometry ICP-MS . Other reagents are of special grade. Instrumental conditions i. X-ray fluorescence analysis Instrument a PW1404 type X-ray fluorescence analysis instrument Philips Almelo Netherlands . 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. .