Abstract
We describe a terbium-ligand complex (TbL) for a microtiterplate assay for phosphate (P) in the 0.3-100 mu mol L-1 range based on luminescence quenching. As the pH optimum is at neutral pH (7.4) the probe is quenched by both, primary (H2PO4-) and secondary phosphate (HPO42-). The LOD is 110 nmol L-1. A Stern-Volmer study revealed that quenching is mostly static. Due to the ms-decay time of TbL, ...
Abstract
We describe a terbium-ligand complex (TbL) for a microtiterplate assay for phosphate (P) in the 0.3-100 mu mol L-1 range based on luminescence quenching. As the pH optimum is at neutral pH (7.4) the probe is quenched by both, primary (H2PO4-) and secondary phosphate (HPO42-). The LOD is 110 nmol L-1. A Stern-Volmer study revealed that quenching is mostly static. Due to the ms-decay time of TbL, the first luminescence lifetime assay for phosphate could also be developed. The lifetime-based calibration plot is linear between 0.5 and 5 mu mol L-1 of P. The effect of various surfactants on assay performance and a study on interferents are presented. The probe was successfully applied to determination of Pin commercial plant fertilizers and validated against the molybdenum blue test. The probe is the most sensitive lanthanide-based probe for phosphate. (C) 2010 Elsevier BM. All rights reserved.
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