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.

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/dm, 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/dm); NH4-oxalate buffer (0.2 mol/dm, pH=3.25); and mixture of NH4-oxalate buffer (0.2 mol/dm) and ascorbic acid (0.1 mol/dm) 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.

A simple and inexpensive method for the determination of arsenic at low ppb levels was developed. The method is based on reduction of arsenite and arsenate in acidic reaction medium to the formation of hydride from sample solution, and its reaction with mercury bromide. Mercury bromide was impregnated on a solid support (filter paper), and formation and detection of a yellow-brownish product was performed spectrophotometrically by using an instrument for field determination of arsenic, Supralab FD. Amidosulfonic acid was used to adjust acidity of the solutions, and reduction of arsenic compounds was done by sodium borohydride. The method was used for the determination of arsenic in soil samples after digestion. The accuracy of the method was determined by analysis of a soil sample reference material (SRM 2710), and by an interlaboratory comparison. Detection limit of the method is 0,06 μg As/dm with limit of quantification of 0,2 μg As/dm.