Novel approaches to the oxidation of paralytic shellfish poisoning toxins for analysis by high-performance liquid chromatography.

摘要

Two new high-performance liquid chromatographic (HPLC) methods were developed for the determination of paralytic shellfish poisoning (PSP) toxins, a group of structurally similar neurotoxins. The methods were based on two different post-column reactions, using either an anode or manganese dioxide to oxidize these toxins to fluorescent purine derivatives which were quantitated using a fluorescence detector. Both oxidative processes involved heterogeneous reactions at a solution-surface interface, which offered the advantage of pumpless reagent delivery.;In studying the post-column electrochemical reactor, the effect of certain reaction conditions on fluorescent produce yield was examined. These experimental parameters included voltage, pH, temperature, and mobile phase flow rate. Other experiments were conducted to improve the chromatography of two of the more highly-retained compounds. The products of the electrochemical reaction were identified using a second HPLC method. After the conditions of oxidation and chromatography were optimized, the post-column electrochemical reaction method was applied to analyze shellfish and plankton samples, yielding results which were in agreement with accepted analytical methods.;The manganese dioxide oxidation of PSP toxins was studied in two parts. The first set of experiments involved batch reactions and the analysis of oxidation products. Detailed studies were conducted on reaction conditions, such as temperature, pH, time, amount of oxidant, and concentration of PSP toxin. Rate constants and activation energies were calculated for the manganese dioxide oxidation or two PSP analogues, saxitoxin and neosaxitoxin. A preliminary HPLC study, employing a UV detector to monitor the oxidation products, was conducted.;The information gathered in the batch experiments was used to develop a solid-phase post-column reactor based on oxidation by manganese dioxide. Experiments were conducted to optimize conditions, such as pH, flow rate, reactor dimensions, and manganese dioxide particle size. The contribution of the reactor to peak-broadening was studied, and the stability of the solid-phase reactor was examined. Under the chosen conditions, the post-column manganese dioxide reactor was successfully used to analyze shellfish and plankton samples.