Cyanobacteria are a small group of photosynthetic planktonic bacteria, which produce a large group of potent hepatotoxins called microcystins (MCs). Waterborne toxins can be found in the aerosol phase due to bubble-bursting processes. It has been demonstrated that some respiratory symptoms can be associated with exposure to high levels of cyanobacteria during recreational activities. While biological assay or physicochemical approaches can reveal the presence of MCs, but not identify which specific toxins are present, chromatographic methods can separate them allowing individual identification. The aim of this study was to obtain a sensitive method for the determination of trace concentrations of individual cyanotoxins in aerosol samples, using an Agilent 1100 series HPLC system (Agilent, Waldbronn, Germany) coupled to an API 4000 triple quadrupole mass spectrometer (Applied Biosystems/MDS SCIEX, Toronto, Ontario, Canada). During method development improved electrospray ionization was found in negative ion mode for the MCs. For this reason, in contrast with others authors, we have developed a chromatographic separation using alkaline conditions, thus achieving good resolution, improved electrospray ionization and therefore better sensitivity. A sensitive analytical method has been obtained for measuring trace concentrations of MC family of cyanotoxins and nodularin in aerosol samples, allowing a simultaneous detection of six MCs (MC-LA, -LY, -YR, -LR, -LW, -LF, and NOD) in a single 27 min chromatographic analysis. The limit of detection for all the toxins were determined to be between 2 fg/?L (-LA and -LF) and 178 fg/?L (NOD), values that are similar or lower than those reported in the literature. In this work the internal standard method has been used for calibration and the analytical procedure was validated by evaluating the accuracy, precision and recovery . The method was applied to seven aerosol samples from the Venice Lagoon. In these samples, trace concentrations of MC-LA ranged between 90 fg m-3 and 706 fg m-3, MC-LF between n.d. - 369 fg m-3 and MC-LW between n.d. - 262 fg m-3.More research needs to be conducted in order to investigate the origin of these compounds in the Venetian atmosphere.
An Alternative Method for Microcystins Analysis in Aerosol Samples.
Roberta Zangrando;Elena Barbaro;ElisaScalabrin;Carlo Barbante
2011
Abstract
Cyanobacteria are a small group of photosynthetic planktonic bacteria, which produce a large group of potent hepatotoxins called microcystins (MCs). Waterborne toxins can be found in the aerosol phase due to bubble-bursting processes. It has been demonstrated that some respiratory symptoms can be associated with exposure to high levels of cyanobacteria during recreational activities. While biological assay or physicochemical approaches can reveal the presence of MCs, but not identify which specific toxins are present, chromatographic methods can separate them allowing individual identification. The aim of this study was to obtain a sensitive method for the determination of trace concentrations of individual cyanotoxins in aerosol samples, using an Agilent 1100 series HPLC system (Agilent, Waldbronn, Germany) coupled to an API 4000 triple quadrupole mass spectrometer (Applied Biosystems/MDS SCIEX, Toronto, Ontario, Canada). During method development improved electrospray ionization was found in negative ion mode for the MCs. For this reason, in contrast with others authors, we have developed a chromatographic separation using alkaline conditions, thus achieving good resolution, improved electrospray ionization and therefore better sensitivity. A sensitive analytical method has been obtained for measuring trace concentrations of MC family of cyanotoxins and nodularin in aerosol samples, allowing a simultaneous detection of six MCs (MC-LA, -LY, -YR, -LR, -LW, -LF, and NOD) in a single 27 min chromatographic analysis. The limit of detection for all the toxins were determined to be between 2 fg/?L (-LA and -LF) and 178 fg/?L (NOD), values that are similar or lower than those reported in the literature. In this work the internal standard method has been used for calibration and the analytical procedure was validated by evaluating the accuracy, precision and recovery . The method was applied to seven aerosol samples from the Venice Lagoon. In these samples, trace concentrations of MC-LA ranged between 90 fg m-3 and 706 fg m-3, MC-LF between n.d. - 369 fg m-3 and MC-LW between n.d. - 262 fg m-3.More research needs to be conducted in order to investigate the origin of these compounds in the Venetian atmosphere.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
