title: Simple and rapid determination of anatoxin-a in lake water and fish muscle tissue by liquid-chromatography-tandem mass spectrometry.
abstract: Anatoxin-a (AN) is a powerful neurotoxin that can be produced by cyanobacteria in eutrophic freshwaters. Consequently, AN can contaminate lakes, rivers and basins destined for drinking water and aquaculture. Two simple, specific and sensitive procedures for determining AN in lake water and fish muscle tissue are presented. Both analytical protocols are based on liquid-chromatography (LC)-tandem mass spectrometry (MS) with electrospray ionization. MS data were acquired in the multi reaction monitoring mode by selecting four precursor to product ion transitions. After filtration, AN in lake water was analyzed by directly injecting 0.5 ml of the aqueous sample in the LC column. Analysis of AN in fish muscle tissue involved the matrix solid-phase dispersion technique. The analyte was extracted from tissue by 4 ml of water acidified to pH 2 and heated at 80 degrees C. After acidification and filtration, 0.2 ml of the aqueous extract was injected in the LC column. Analyte recovery ranged between 71 and 79% and was not substantially affected by both the analyte concentration and the type of fish. Phenylalanine is an essential amino acid invariably present in any animal tissue. Like AN, this amino acid produces a pseudo molecular ion at m/z 166, it has a very similar fragmentation pattern and LC retention time. This method is able to prevent identifying phenylalanine for AN as the latter compound is eluted more than 1 min before the former one and the two compounds have remarkably different relative ion signal intensities. On the basis of a signal-to-noise ratio of 10, limits of quantification of AN in water and fish fillet were estimated to be 13 ng/l and 0.5 ng/g, respectively.
authors.affiliation: Dipartimento di Chimica, Università La Sapienza, Piazza Aldo Moro 5, 00185 Roma, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Bogialli
authors.forename: Milena
authors.initials: M
authors.lastname: Bruno
authors.forename: Roberta
authors.initials: R
authors.lastname: Curini
authors.forename: Antonio
authors.initials: A
authors.lastname: Di Corcia
authors.forename: Aldo
authors.initials: A
authors.lastname: Laganà
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000032:analysis*; D002853:Chromatography, Liquid / Q000379:methods*; D000087522:Cyanobacteria Toxins; D005399:Fishes / Q000378:metabolism*; D005618:Fresh Water / Q000737:chemistry*; D008387:Marine Toxins / Q000032:analysis*; D013058:Mass Spectrometry / Q000379:methods*; D052998:Microcystins; D009132:Muscles / Q000737:chemistry*; D015203:Reproducibility of Results; D014326:Tropanes
chemical_list: D001427:Bacterial Toxins; D000087522:Cyanobacteria Toxins; D008387:Marine Toxins; D052998:Microcystins; D014326:Tropanes; C509783:anatoxin a