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Determination of arsenate and phosphate in rainwater: Preconcentration bt membrane filtration
Author(s) -
Matsubara Chiyo,
Yoshihara Kazuhiro,
Ejima Hirofumi,
Takamura Kiyoko
Publication year - 1990
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/aoc.590040319
Subject(s) - arsenate , chemistry , malachite green , phosphate , absorbance , molybdate , molar absorptivity , chromatography , permanganate , membrane , filtration (mathematics) , arsenic , inorganic chemistry , nuclear chemistry , reagent , adsorption , organic chemistry , biochemistry , statistics , mathematics , optics , physics
A simple and rapid method for the determining arsenate and phosphate in rainwater is proposed. These compounds form molybdoarsenate– and molybdophosphate–Malachite Green aggregates with MoMG reagent (MoMG = a mixture of ammouium molybdate and Malachite Green). The aggregates were first collected on a nitrocellulose membrane filter (pore size 3μm) and then dissolved with the filter in a small amount of 2‐methoxyethanol. Absorbance (627 nm), denoted as A(As + P), was found to be proportional to the sum of the arsenate and phosphate concentrations with a molar absorptivity of 2.8 × 10 5 (mol dm −3 ) −1 cm −1 . Following the addition of thiosulphate, an agent which reduces arsenate, the absorbance A (P) was measured as described above. A (P) corresponded to the concentration of phosphate alone and A (As + P)– A (P), to arsenate concentration only. This method is shown to be a rapid and highly accurate means for determining arsenate and phosphate levels within the 1–150 nmol dm −3 concentration range.