UDK 631.4:546.19 A simple and inexpensive method for the determination of inorganic As(III) and As(V) at low ppb levels was developed. The method is based on formation of hydride from a sample solution and its reaction with mercury bromide on a solid support. Formation of a yellow-brownish product was optically detected. Amidosulfonic acid was used as a reaction medium for determination of total inorganic arsenic, while citrate buffer (0.1 mol/dm3, pH=5.5) was used as a reaction media for determination of As(III) alone. As(V) was calculated as a difference of total inorganic arsenic and As(III). This method has been applied to soil extracts. Extraction of inorganic arsenic from soil samples was done in three-step sequential extraction with the following extractants: NH4H2PO4 (0.05 mol/dm3); NH4-oxalate buffer (0.2 mol/dm3, pH=3.25); and mixture of NH4-oxalate buffer (0.2 mol/dm3) and ascorbic acid (0.1 mol/dm3) at pH=3.25. The method was suitable for determination of inorganic arsenic species in soil extracts covering concentration range of the analyte between 0.2 - 20 ppb.

UDK 546.19:543.422.3 Razvijena je jednostavna i jeftina metoda za određivanje arsena u niskom ppb području. Metoda je zasnovana na redukciji arsenita i arsenata u kiseloj reakcionoj sredini do gasovitog produkta hidrida arsena, arsina i njegovoj reakciji sa živa(II) bromidom. Živa(II) bromid je impregniran na čvrsti nosač (filter papir), a formiranje i detekcija žuto-smeđeg produkta je vršena spektrofotometrijski, upotrebom instrumenta za terensko određivanje arsena, Supralab FD. Za podešavanje kiselosti rastvora korištena je amidosulfonska kiselina, a redukcija arsena je vršena natrij borhidridom. Metoda je korištena u određivanju arsena u uzorcima zemljišta nakon digestije. Validacija metode je izvršena upotrebom standardnog referentnog materijala (SRM 2710) i interlaboratorijskom komparacijom analizom sa ICP-MS. Limit detekcije razvijene metode je 0,06 mg As/dm3 sa limitom kvantifikacije od 0,2 mg As/dm3.