Safety issues in nutraceutical exploitation of Chlorella vulgaris, Arthrospira Platensis and Scenedesmus sp. microalgae

Microalgae contain many bioactive compounds, which may be exploited in food and nutraceutical fields. Bisphenol A (BPA) is a contaminant in microalgae that may be released from polymeric plastics. Since it is responsible for toxic effects on humans, the European legislation set the legal BPA limit within foods at 50 & mu;g kg-1 of food weight. In this work, a fast ultrasounds solid-liquid extraction of BPA from commercial microalgal powders of Chlorella vulgaris, Arthrospira Platensis and Scenedesmus sp. was optimized. To increase selectivity, BPA was derivatized by using N,O-bis(trimethylsilyl)trifluoroacetamide/trimethylchlorosilane (BSTFA-TMCS) and it was analysed by GC-MS in selected ion monitoring mode. A design of experiment (DOE) optimization study of the reaction conditions was performed. The analytical method was validated by determining selectivity, linearity (R2= 0.99999 & PLUSMN; 3.3165E-07), precision, accuracy (99.92 & PLUSMN; 9.83E-02 %), recovery (99.65 & PLUSMN; 3.61E-02 %) and sensitivity (LoD= 0.547 & PLUSMN; 9.94E-02 & mu;g kg � 1; LoQ= 1.823 & PLUSMN; 3.31E-1 & mu;g kg � 1). The overall method proved to be fast, with high recovery and suitable to selectively and sensitively determine the content of BPA, eliminating the interferences from extraction and allowing to control the safety profile of microalgae. Dried microalgae cultivated in a polycarbonate reactor, were found to contain an amount of BPA 6 times exceeding the legal limit.