Interference from arsenate when determining phosphate by the malachite green spectrophotometric method

K.L. Linge, Carolyn Oldham

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

The effect of arsenate on phosphate determination by the malachite green spectrophotometric method was investigated. The molar absorptivities of the molybdophosphate and malachite green-molybdoarsenate species at 625 nm and a final acidity of 0.38 M were calculated as 10.4 +/- 0.13 x 10(4) and 7.2 +/- 0.17 x 10(4) 1 mol(-1) cm(-1) respectively, indicating that arsenate could interfere in phosphate measurement. Arsenate concentrations as low as 23 mug 1(-1) caused increase in colour development in phosphate solutions. However, the extent of colour development for both anions depended on the final acid concentration of the solution. An acidified sodium sulphite solution (0.83 M NaSO3, 0.83 M H2SO4) quantitatively prevented arsenate colour development up to 300 mug 1(-1) As(V). It was also demonstrated that the method removed As(V) interferences in mixed As/P solutions and therefore can be used to treat natural water samples with elevated arsenate concentrations before phosphate measurement. (C) 2001 Elsevier Science B.V. All rights reserved.
Original languageEnglish
Pages (from-to)247-252
JournalAnalytica Chimica Acta
Volume450
Issue number1-2
DOIs
Publication statusPublished - 2001

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malachite
arsenate
Phosphates
phosphate
Color
sulfite
Acidity
Anions
acidity
anion
sodium
method
arsenic acid
malachite green
Acids
Water
acid
water

Cite this

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title = "Interference from arsenate when determining phosphate by the malachite green spectrophotometric method",
abstract = "The effect of arsenate on phosphate determination by the malachite green spectrophotometric method was investigated. The molar absorptivities of the molybdophosphate and malachite green-molybdoarsenate species at 625 nm and a final acidity of 0.38 M were calculated as 10.4 +/- 0.13 x 10(4) and 7.2 +/- 0.17 x 10(4) 1 mol(-1) cm(-1) respectively, indicating that arsenate could interfere in phosphate measurement. Arsenate concentrations as low as 23 mug 1(-1) caused increase in colour development in phosphate solutions. However, the extent of colour development for both anions depended on the final acid concentration of the solution. An acidified sodium sulphite solution (0.83 M NaSO3, 0.83 M H2SO4) quantitatively prevented arsenate colour development up to 300 mug 1(-1) As(V). It was also demonstrated that the method removed As(V) interferences in mixed As/P solutions and therefore can be used to treat natural water samples with elevated arsenate concentrations before phosphate measurement. (C) 2001 Elsevier Science B.V. All rights reserved.",
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Interference from arsenate when determining phosphate by the malachite green spectrophotometric method. / Linge, K.L.; Oldham, Carolyn.

In: Analytica Chimica Acta, Vol. 450, No. 1-2, 2001, p. 247-252.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Interference from arsenate when determining phosphate by the malachite green spectrophotometric method

AU - Linge, K.L.

AU - Oldham, Carolyn

PY - 2001

Y1 - 2001

N2 - The effect of arsenate on phosphate determination by the malachite green spectrophotometric method was investigated. The molar absorptivities of the molybdophosphate and malachite green-molybdoarsenate species at 625 nm and a final acidity of 0.38 M were calculated as 10.4 +/- 0.13 x 10(4) and 7.2 +/- 0.17 x 10(4) 1 mol(-1) cm(-1) respectively, indicating that arsenate could interfere in phosphate measurement. Arsenate concentrations as low as 23 mug 1(-1) caused increase in colour development in phosphate solutions. However, the extent of colour development for both anions depended on the final acid concentration of the solution. An acidified sodium sulphite solution (0.83 M NaSO3, 0.83 M H2SO4) quantitatively prevented arsenate colour development up to 300 mug 1(-1) As(V). It was also demonstrated that the method removed As(V) interferences in mixed As/P solutions and therefore can be used to treat natural water samples with elevated arsenate concentrations before phosphate measurement. (C) 2001 Elsevier Science B.V. All rights reserved.

AB - The effect of arsenate on phosphate determination by the malachite green spectrophotometric method was investigated. The molar absorptivities of the molybdophosphate and malachite green-molybdoarsenate species at 625 nm and a final acidity of 0.38 M were calculated as 10.4 +/- 0.13 x 10(4) and 7.2 +/- 0.17 x 10(4) 1 mol(-1) cm(-1) respectively, indicating that arsenate could interfere in phosphate measurement. Arsenate concentrations as low as 23 mug 1(-1) caused increase in colour development in phosphate solutions. However, the extent of colour development for both anions depended on the final acid concentration of the solution. An acidified sodium sulphite solution (0.83 M NaSO3, 0.83 M H2SO4) quantitatively prevented arsenate colour development up to 300 mug 1(-1) As(V). It was also demonstrated that the method removed As(V) interferences in mixed As/P solutions and therefore can be used to treat natural water samples with elevated arsenate concentrations before phosphate measurement. (C) 2001 Elsevier Science B.V. All rights reserved.

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DO - 10.1016/S0003-2670(01)01388-5

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JO - Analytica Chimica Acta

JF - Analytica Chimica Acta

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