DETERMINATION OF MICROCYSTIN-LR IN CYANOBACTERIAL BLOOMS FROM THE MOGI GUAÇU RIVER (BRAZIL) BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY

Abstract

This article focuses on the determination of cyanotoxin microcystin-LR using techniques such as solid-phase extraction (SPE) and HPLC-DAD for the detection and quantification of microcystin-LR in cyanobacterial blooms, which are frequently present in fee-fishing ponds and fish farms. Tests performed with SPE showed that this procedure was not necessary for all samples because there were cases in which no changes were obtained at the interfering peaks near the retention time of the studied analyte. However, because composition of such samples is very complex and varies greatly, the SPE must be promoted, although this process requires a lengthier analysis time frame and an increase in cost. The method was validated in accordance with the Brazilian National Health Surveillance Agency (ANVISA) and FDA. The limit of detection was set at 0.1 igmL ∼2 and the limit of quantification at 0.5 figmL-1. The analytical curve obtained, y = 21.849 x + 1.5888, with r = 0.9950, showed good linearity. Microcystin-LR was detected in more than half of the cyanobacterial blooms samples analyzed, being also quantified in two of them. This procedure showed the importance of analyzing microcystin-LR in cyanobacterial blooms in order to evaluate water quality and safety offish consumption.

Keywords:

• cyanobacteria
• cyanotoxin
• HPLC
• microcystin-LR
• microcystis aeruginosa
• mogi guaçu river

ACKNOWLEDGMENT

The authors would like to thank the Sao Paulo Research Foundation (FAPESP) and National Council for Scientific and Technological Development (CNPq).

Notes

*Percentages in v/v.

^*Initial proportion in the gradient program.