Neutron activation analysis of arsenic in rocks and sediments by direct evolution with chloride- and bromide-condensed phosphoric acid reagents

Journal of Radioanalytical and Nuclear Chemistry - Tập 36 - Trang 47-58 - 1977
K. Terada1, K. Okuda1, T. Kiba1
1Department of Chemistry, Faculty of Science, Kanazawa University, Kanazawa, Japan

Tóm tắt

A simple method is presented for the determination of arsenic in rocks and in sediments by neutron activation. After irradiating a sample it is, without any other treatment, directly heated in condensed phosphoric acid containing sodium chloride or sodium bromide to evolve arsenic as arsenic(III) chloride or bromide. The distillate is absorbed in distilled water, in which arsenic is later precipitated in elementary form by adding hypophosphite to the solution. From arsenite, arsenic(III) oxide, arsenate and arsenic(III) sulphide, arsenic chloride can be evolved with NaCl-CPA reagent, but elementary arsenic and arsenic(V) oxide do not react with it. However, metallic arsenic is found to react with KIO3-NaCl-CPA and arsenic(V) oxide with the NaBr-CPA, both both evolving arsenic(III) chloride or bromide. Therefore, successive distillations, the first with NaCl-CPA and the second with NaBr-CPA, give a satisfactory means of differential determination of arsenic(III) and arsenate as well as arsenic(V) oxide. For the elementary arsenic a problem still now remains. The chemical recovery of carrier goes well beyond 95%.

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Thông tin
Thông tin xuất bản

Journal of Radioanalytical and Nuclear Chemistry

Tập 36

47-58

Thông tin tác giả