An enzymatic flow analysis method for the determination of phosphatidylcholine in sediment pore waters and extracts

A sensitive and selective flow injection method for the determination of phosphatidylcholine (PC) in sediment pore waters and extracts is described. It involves the use of phospholipase C, alkaline phosphatase and choline oxidase co-immobilized on controlled pore glass in a packed column reactor. The final product of the enzymatic reaction of phosphatidylcholine is hydrogen peroxide, and this is detected by measuring the chemiluminescence emission resulting from cobalt(II) catalysed reaction with luminol. The flow injection method is rapid (30 injections/h), reproducible (1.4% R.S.D. at 3 microM PC, n=10) with a detection limit of 0.14 microM (estimated from 3sigma(n-1) of the measured blank). A linear calibration response was obtained over a concentration range of 0.5-9 microM (r=0.999). The method has been applied to the determination of phosphatidylcholine in sediment extracts and sediment pore waters.