Determination of Cr ( III) in tap water with sodium poly (aspartic acid) as a binding phase in diffusive gradients in thin-films

Cr ( III) in tap water was measured by the diffusive gradients in thin-films ( DGT) technique using 0.05mol /L sodium poly ( aspartic acid) ( PASP) as binding phase ( PASP DGT) .The recoveries of Cr ( III) in prepared solutions measured by PASP DGT were 94.4% ~ 105.6% with relative standard deviation ( RSD) 2.78% ~ 5.03%.The concentration of Cr ( III) in tap water measured by PASP DGT was 2.99³.47μg /L with recoveries of 93.2% ¹07.7%.The method detect limit for PASP DGT was 0.081μg /L ( deployment time 48h) .Therefore, PASP DGT can be used to measure trace Cr ( III) and give an early alarm in tap water.