| 1. |
- Rosén, Johan, et al.
(författare)
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A new method for analysis of underivatized free beta-methylamino-alanine : Validation and method comparison
- 2016
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Ingår i: Toxicon. - : Elsevier BV. - 0041-0101 .- 1879-3150. ; 121, s. 105-108
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Tidskriftsartikel (refereegranskat)abstract
- A new method was developed for analysis of free beta-Methylamino-alanine (BMAA) in biological matrices. The method is based on direct analysis of the underivatized molecule, using an amide column for separation by Hydrophilic Interaction Liquid Chromatography (HILIC) and detection by tandem mass spectrometry (MS/MS) using a deuterium labeled internal standard. The use of Ultra-High Performance Liquid Chromatography (UHPLC) combined with MS/MS detection allowed for high chromatographic resolution and a low limit of detection (0.025 mu g/g wet weight (ww) in mussels). The method was validated by analyzing spiked blank mussels from the Baltic Sea (0.15-4.4 mu g/g (ww), trueness 99%-105%, RSD 2%-8%). An inter-laboratory comparative analysis of extracts of mussel was performed. The mussels were extracted according to an established protocol for analysis of free BMAA, and the extracts were then analyzed in parallel by the new method and a validated procedure based on detection of BMAA derivatized with dansyl chloride. Both methods detected BMAA in similar concentrations. Thus, derivatization with dansyl chloride did not influence the results compared to direct detection. The new method presents an alternative to the commonly applied derivatization step, and is proved through validation and method comparison to reliably identify and quantify free BMAA at low concentration levels.
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| 2. |
- Salomonsson, Matilda L., et al.
(författare)
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Quantification of dimethylsulfoxide (DMSO) in equine plasma and urine using HILIC-MS/MS
- 2017
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Ingår i: Drug Testing and Analysis. - : WILEY. - 1942-7603 .- 1942-7611. ; 9:6, s. 935-941
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes quantitative methods for the determination of dimethylsulfoxide (DMSO) in equine plasma and urine based on simple precipitation and dilution followed by hydrophilic interaction liquid chromatography coupled to tandem mass spectrometry (HILIC-MS/MS). DMSO is a polar solvent with analgesic and anti-inflammatory properties. Its pharmacological features make it prohibited in horse racing. However, since DMSO is naturally present in the horses' environment, international threshold values have been implemented for plasma and urine (1 and 15 mu g/mL, respectively). Previously presented quantitative methods for the determination of DMSO are based on gas chromatography, thus demanding a tedious extraction step to transfer the analyte from the aqueous bodily fluid to an injectable organic solvent. The column used in the presented method was an Acquity BEH HILIC and the mobile phase was a mixture of ammonium acetate buffer and acetonitrile delivered as a gradient. Hexadeuterated DMSO (H-2(6)-DMSO) was used as the internal standard. Validation was performed in the range of the international thresholds concerning selectivity, carry-over, linearity, precision, accuracy, stability and inter-individual matrix variation. The results fulfilled the predefined criteria and the methods were considered fit for purpose. Successful applications on real equine doping control samples were carried out with determined DMSO concentrations exceeding the international thresholds.
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