Silicate Correction in the Colorimetric Determination of Phosphate in Seawater

Abstract

An improved Strickland and Parsons' method, in which silicate correction is made, is described for the colorimetric determination of phosphate in seawater. Silicate correction is made by subtracting the value of 0.025 (C/100) ², whereCis silicate concentration (μg atoms 1-1), from the observed phosphate concentration. The relative standard deviations are 2% at the 1 μg atom PO₄^3--Pl^-1level and less than 1 % at the 3 μg atoms PO₄^3--P1^-1 level in seawater.