Domoic acid (DA) is a neurotoxic tricarboxylic amino acid responsible for amnesic shellfish poisoning and is secreted by the diatom genus Pseudo-nitzschia. We have developed two very sensitive instrumental methods using hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry using respectively positive and negative polarity (HILIC-ESI(+/-)-MS/MS). Instrumental detection limits were 9 fg µL-1 with positive ionization and 19 fg µL-1 for negative one, values much lower than those reported in literature. A procedural method based on a solid phase extraction for the determination of dissolved DA present in seawater has been developed, while an extraction procedure was employed for toxin determination in the particulate fraction. DA quantification was performed using internal standard method obtaining many advantages such as the consideration of signals fluctuations, of matrix effect, of casual errors during the sample treatments and the reduction of process schedule. To our knowledge, this is the first study to use this quantification method for DA determination. Trueness, extraction yield, matrix effect, repeatability and procedural detection limits were evaluated to method validation. Procedural detection limits of 0.3 fg µL-1 and 0.6 fg µL-1 for dissolved fraction with positive ionization and 0.4 pg absolute and 6 pg absolute for particulate samples with negative one were obtained, better values than those reported in literature. The developed method was applied to seawater samples from the Venice Lagoon, where DA concentrations were ranged between 1.47 and 16.15 fg µL-1. This is the first study to investigate the domoic acid concentration in the Venice Lagoon. Due to innovative and sensitive methods developed in this research, other further studies will be performed in order to assess the origin and the possible factors which may contribute to the toxin production in this environment.
Hydrophilic Interaction Liquid Chromatography in Very Sensitive HPLC-MS/MS Methods for the Determination of Neurotoxic Domoic Acid in Lagoon Samples
Elena Barbaro;Roberta Zangrando;Carlo Barbante;Andrea Gambaro
2013
Abstract
Domoic acid (DA) is a neurotoxic tricarboxylic amino acid responsible for amnesic shellfish poisoning and is secreted by the diatom genus Pseudo-nitzschia. We have developed two very sensitive instrumental methods using hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry using respectively positive and negative polarity (HILIC-ESI(+/-)-MS/MS). Instrumental detection limits were 9 fg µL-1 with positive ionization and 19 fg µL-1 for negative one, values much lower than those reported in literature. A procedural method based on a solid phase extraction for the determination of dissolved DA present in seawater has been developed, while an extraction procedure was employed for toxin determination in the particulate fraction. DA quantification was performed using internal standard method obtaining many advantages such as the consideration of signals fluctuations, of matrix effect, of casual errors during the sample treatments and the reduction of process schedule. To our knowledge, this is the first study to use this quantification method for DA determination. Trueness, extraction yield, matrix effect, repeatability and procedural detection limits were evaluated to method validation. Procedural detection limits of 0.3 fg µL-1 and 0.6 fg µL-1 for dissolved fraction with positive ionization and 0.4 pg absolute and 6 pg absolute for particulate samples with negative one were obtained, better values than those reported in literature. The developed method was applied to seawater samples from the Venice Lagoon, where DA concentrations were ranged between 1.47 and 16.15 fg µL-1. This is the first study to investigate the domoic acid concentration in the Venice Lagoon. Due to innovative and sensitive methods developed in this research, other further studies will be performed in order to assess the origin and the possible factors which may contribute to the toxin production in this environment.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.