title: High resolution/accurate mass (HRMS) detection of anatoxin-a in lake water using LDTD-APCI coupled to a Q-Exactive mass spectrometer.
abstract: A new innovative analytical method combining ultra-fast analysis time with high resolution/accurate mass detection was developed to eliminate the misidentification of anatoxin-a (ANA-a), a cyanobacterial toxin, from the natural amino acid phenylalanine (PHE). This was achieved by using the laser diode thermal desorption-atmospheric pressure chemical ionization (LDTD-APCI) coupled to the Q-Exactive, a high resolution/accurate mass spectrometer (HRMS). This novel combination, the LDTD-APCI-HRMS, allowed for an ultra-fast analysis time (<15 s/sample). A comparison of two different acquisition modes (full scan and targeted ion fragmentation) was made to determine the most rigorous analytical method using the LDTD-APCI interface. Method development focused toward selectivity and sensitivity improvement to reduce the possibility of false positives and to lower detection limits. The Q-Exactive mass spectrometer operates with resolving powers between 17500 and 140000 FWHM (m/z 200). Nevertheless, a resolution of 17500FWHM is enough to dissociate ANA-a and PHE signals. Mass accuracy was satisfactory with values below 1 ppm reaching precision to the fourth decimal. Internal calibration with standard addition was achieved with the isotopically-labeled (D5) phenylalanine with good linearity (R(2)>0.999). Enhancement of signal to noise ratios relative to a standard triple-quadrupole method was demonstrated with lower detection and quantification limit values of 0.2 and 0.6 μg/L using the Q-Exactive. Accuracy and interday/intraday relative standard deviations were below 15%. The new method was applied to 8 different lake water samples with signs of cyanobacterial blooms. This work demonstrates the possibility of using an ultra-fast LDTD-APCI sample introduction system with an HRMS hybrid instrument for quantitative purposes with high selectivity in complex environmental matrices.
authors.affiliation: Department of Chemistry, Université de Montréal, Montréal, QC, Canada.
authors.forename: Audrey
authors.initials: A
authors.lastname: Roy-Lachapelle
authors.affiliation: Department of Chemistry, Université de Montréal, Montréal, QC, Canada.
authors.forename: Morgan
authors.initials: M
authors.lastname: Solliec
authors.affiliation: Direction du Suivi de l'État de l'Environnement (DSEE), Ministère du développement durable, de l'environnement et de lutte aux changements climatiques (MDDELCC), Québec, QC, Canada.
authors.forename: Marc
authors.initials: M
authors.lastname: Sinotte
authors.affiliation: Centre d'expertise en analyse environnementale (CEAEQ), Ministère du développement durable, de l'environnement et de lutte aux changements climatiques (MDDELCC), Québec, QC, Canada.
authors.forename: Christian
authors.initials: C
authors.lastname: Deblois
authors.affiliation: Department of Chemistry, Université de Montréal, Montréal, QC, Canada. Electronic address: sebastien.sauve@umontreal.ca.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Sauvé
mesh_terms: D017033:Anabaena / Q000737:chemistry; D002138:Calibration; D000087522:Cyanobacteria Toxins; D057097:Harmful Algal Bloom; D060106:Lakes; D057230:Limit of Detection; D013058:Mass Spectrometry / Q000295:instrumentation / Q000379:methods*; D015588:Observer Variation; D010649:Phenylalanine / Q000032:analysis; D012015:Reference Standards; D013997:Time Factors; D014326:Tropanes / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D000087522:Cyanobacteria Toxins; D014326:Tropanes; D014874:Water Pollutants, Chemical; D010649:Phenylalanine; C509783:anatoxin a
keywords: Anatoxin-a; Cyanobacteria; High resolution mass spectrometry; LDTD–APCI; Phenylalanine