Low levels of chromatic substances cause severe interference with traditional phosphorus assays. Even clear sera may contain high levels of free fatty acids, phospholipids or abnormal proteins which form turbidity during the course of traditional assays.
Phosphorus assays have been used to monitor intravenous nutrition in geriatric poulations receiveing Intralipid®. The Intralipid causes severe interference in traditional phosphorus assays providing misleading information.
The Synermed® phosphorus assay avoids interference from abnormal proteins, chromatic substances and other turbidity related interferences by means of kinetic infrared detection.
Synermed provides liquid, stable reagents for the measurement of phosphorus. In the Synermed method, polyvinylpyrrolidone is used to catalyze the reaction of phosphorus with molybdate. The phospho-molybdate complex is reduced in the second step, producing an intense blue infrared-absorbing chromophore which can be quantitated between 600 nm and 850 nm. The infrared detection of the Synermed method eliminates chromatic interferences from hemolysis, bilirubin, and lipemia. The Synermed method is also free from interference from protein.
Polyvinylpyrrolidone [PVP] catalyzes the formation of the molybdate polymer which reacts with phosphorus to form a phosphomolybdate complex.
H3PO4 + MoVI -> 12-molybdophosphoric acid + H+
The phosphomolybdate complex is reduced to form an intense infrared absorbing blue chromophore which is quantitated spectrophotometrically between 600 and 850 nm.
12-molybdophosphoric acid + e- -> phosphomolybdenum blue