Spectrophotometric determination of the total amount of rare-earth elements in agricultural samples with p-chloro-chlorophosphonazo.
A simple, sensitive and accurate spectrophotometric method for determination of the total amount of rare-earth elements in agricultural samples with p-chloro-chlorophosphonazo [pCCPA, i.e., 2-(4'-chloro-2'-phosphon-benzylazo)-7-(4''-chlorophenyl)-1,8-dihydroxynaphthalene-3,6-disulphonic acid] in sulphuric acid medium has been developed. The apparent molar absorptivity of RExOy (the general formula of rare-earth oxides)-pCCPA complex is 8.17 x 10(4) 1.mole(-1) cm(-1) at 676 nm, and Beer's law is obeyed for the mixture of RExOy in the range 0-12 mug/25 ml. The proposed method has been successfully applied to the determination of the total amount of rare-earth elements in soils, herbs, vegetables, dried stems of maize, water samples and rare-earth microelement fertilizer samples with satisfactory results.
Li
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Department of Basic Sciences, Shanxi Agricultural University, Taigu, People's Republic of China.
Li
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Zhang
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