Document Type

Article

Rights

This item is available under a Creative Commons License for non-commercial use only

Disciplines

1.6 BIOLOGICAL SCIENCES, Marine biology

Publication Details

Journal of Chromatography A. Access the journal here http://www.sciencedirect.com/science?_ob=ArticleListURL&_method=list&_ArticleListID=1585572717&_sort=r&_st=13&view=c&_acct=C000056897&_version=1&_urlVersion=0&_userid=2322584&md5=b084ef5bc00d5ffc6dc3def54f039632&searchtype=a

Abstract

Considerable efforts are being made worldwide to replace in vivo assays with instrumental methods of analysis for the monitoring of marine biotoxins in shellfish. Analysis of these compounds by the preferred technique of LC-MS/MS is challenged by matrix effects associated with shellfish tissue components. In methods validation, assessment of matrix interferences is imperative to ensure the accuracy of analytical results. We evaluated matrix interferences in the analysis of okadaic acid (OA) and azaspiracid 1 (AZA1) in mollucscan shellfish by using a conventional acidic method on electrospray triple stage quadrapole (TSQ) and hybrid quadrupole time of flight (QToF) instruments, with matrix matched standards for several species. Using the acidic method, we found no matrix interferences for OA, and matrix suppression for AZA1, with the TSQ instrument; in contrast, we found matrix enhancement for OA, and no matrix interference for AZA1, with QToF. The suppression of AZA1 signal on the TSQ instrument was due to interfering compounds carried over from previous injections. The degree of suppression was dependent on the tissue type, ranging from 20 to 70%. Several strategies were evaluated to eliminate these interferences, including the partitioning of the extract with hexane, optimization of the chromatographic method, and the use of on-line SPE. The use of an alkaline method and a modified acidic method eliminated matrix suppression for AZA1 on the TSQ instrument, while an on-line SPE method proved effective in eliminating matrix enhancement of OA on the QToF.