Capillary electrophoresis tandem mass spectrometry to determine multiclass cyanotoxins in reservoir water and spinach samples.

Cyanotoxins constitute a group of toxic secondary metabolites, the presence of which in any water body poses a major health risk. Moreover, advanced organisms such as edible plants exposed to these toxins, are a possible pathway for human exposure. Green analytical chemistry is demanding environmentally friendly analytical techniques. In this sense, we propose the use of capillary electrophoresis coupled to tandem mass spectrometry (CE-MS/MS) to determine a mixture of eight cyanotoxins belonging to three different classes: cyclic peptides (microcystin-LR, microcystin-RR and nodularin), alkaloids (cylindrospermopsin and anatoxin-a) and three isomeric non-protein amino acids (ß-methylamino-l-alanine, 2,4-diaminobutyric acid and N-(2-aminoethyl)glycine). Separation was achieved by using an acidic background electrolyte consisting of 2 M formic acid and 20% acetonitrile in water. Parameters affecting MS/MS detection and the sheath-liquid interface were also studied. Finally, a combination of pH-junction, field-amplified sample stacking (FASS) and acid barrage as online preconcentration strategies, was employed to improve sensitivity and efficiency. The online preconcentration applied, in combination with a dual cartridge solid-phase extraction (SPE) system, allows to obtain limits of detection in the very low range of µg·L-1 for these multiclass cyanotoxins in reservoir water samples (from 0.005 to 0.10 µg·L-1). Furthermore, for the first time cyanotoxins are analysed in spinach samples through CE-MS/MS using the same SPE procedure, following lyophilisation and solid-liquid extraction with 6 mL 80 % aqueous MeOH.

Determination of Multiclass Cyanotoxins in Blue-Green Algae (BGA) Dietary Supplements Using Hydrophilic Interaction Liquid Chromatography-Tandem Mass Spectrometry.

In recent years, the consumption of blue-green algae (BGA) dietary supplements is increasing because of their health benefits. However, cyanobacteria can produce cyanotoxins, which present serious health risks. In this work we propose hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry (HILIC-MS/MS) to determine cyanotoxins in BGA dietary supplements. Target toxins, including microcystin-leucine-arginine (MC-LR) and microcystin-arginine-arginine (MC-RR), nodularin, anatoxin-a and three non-protein amino acids, ß-N-methylamino-L-alanine (BMAA), 2,4-diaminobutyric acid (DAB) and N-(2-aminoethyl)glycine (AEG), were separated using a SeQuant ZIC-HILIC column. Cyanotoxin extraction was based on solid-liquid extraction (SLE) followed by a tandem-solid phase extraction (SPE) procedure using Strata-X and mixed-mode cation-exchange (MCX) cartridges. The method was validated for BGA dietary supplements obtaining quantification limits from 60 to 300 µg·kg-1. Nine different commercial supplements were analyzed, and DAB, AEG, and MCs were found in some samples, highlighting the relevance of monitoring these substances as precaution measures for the safe consumption of these products.

Collision cross section (CCS) as a complementary parameter to characterize human and veterinary drugs.

In the context of human and veterinary drugs identification, ion mobility spectrometry (IMS) in combination with mass spectrometry (MS) may provide a relevant complementary piece of information to mass-to-charge ratio (m/z), the so-called collision-cross-section (CCS). Up to now, however, the application of CCS as identification parameter has not been fully investigated due to the reduced number of these drugs that have being characterized in terms of CCS. This work proposes a CCS database for 92 human and veterinary drugs, including eighteen benzimidazoles, eleven 5-nitroimidazoles, eleven aminoglycosides, nineteen quinolones, eighteen ß-lactams, ten sulfonamides and five tetracyclines. Among them, 37 drugs have been characterized in terms of CCS for the first time. The CCS values of the other 55 compounds have been compared with those from a recently published database in order to evaluate inter-laboratory reproducibility, which is crucial for the implementation of the CCS as identification parameter. CCS values were measured by traveling wave ion mobility spectrometry (TWIMS) under positive ionization conditions. Nitrogen was used as drift gas in the ion mobility cell. The proposed database covers 173 ions including [M+H]+ and [M+Na]+ species. High correlation between m/z and CCS has been observed for [M+H]+ (R2 = 0.9518, n = 91) and [M+Na]+ (R2 = 0.9135, n = 82) ions. As expected, CCS values for sodium adducts are generally greater than for protonated molecules because they exhibit higher molecular weight. However, sodium adducts of aminoglycosides, ß-lactams, and of several quinolones and benzimidazoles, were characterized as more compact ions than their related protonated molecule. In addition, this work describes the fragmentation pattern observed for the studied molecules. For the first time, the main fragment ions for most of the compounds have also been characterized in terms of CCS, involving a total of 238 ions. As proof of concept, for the application of this database to biological matrices, eleven veterinary drugs in bovine urine samples were characterized in terms of CCS, showing that this parameter was not influenced by the matrix.