Rapid UPLC-MS/MS method for routine analysis of plasma pristanic, phytanic, and very long chain fatty acid markers of peroxisomal disorders

Abstract

Quantification of pristanic acid, phytanic acid, and very long chain fatty acids (i.e., hexacosanoic, tetracosanoic, and docosanoic acids) in plasma is the primary method for investigateing a multitude of peroxisomal disorders (PDs). Typically based on GC-MS, existing methods are time-consuming and laborious. In this paper, we present a rapid and specific liquid chromatography tandem mass spectrometric method based on derivatization with 4-[2-(N,N-dimethylamino)ethylaminosulfonyl]-7-(2-aminoethylamino)-2,1,3-benzoxadiazole (DAABD-AE). Derivatization was undertaken to improve the poor mass spectrometric properties of these fatty acids. Analytes in plasma (20 ml) were hydrolyzed, extracted, and derivatized with DAABD-AE in ?2 h. Derivatives were separated on a reverse-phase column and detected by positive-ion electrospray ionization tandem mass spectrometry with a 5 min injection-to-injection time. Calibration plots were linear over ranges that cover physiological and pathological concentrations. Intraday (n 5 12) and interday (n 5 10) variations at low and high concentrations were less than 9.2%. Reference intervals in normal plasma (n 5 250) were established for each compound and were in agreement with the literature. Using specimens from patients with established diagnosis (n 5 20), various PDs were reliably detected. In conclusion, this method allows for the detection of at least nine PDs in a 5 min analytical run. Furthermore, this derivatization approach is potentially applicable to other disease markers carrying the carboxylic

Isothiocyanates as derivatization reagents for amines in liquid chromatography/electrospray ionization–tandem mass spectrometry

“…It was successfully applied to the determination of oxosteroids such as testosterone. DAABD-AE (Santa et al, 2007b;Al-Dirbashi et al, 2008) was a reagent for carboxylic acids. The C-S bond of the aromatic sulfonyl structure was effi ciently cleaved and gave a product ion at m/z 151.…”

A liquid chromatography–tandem mass spectrometry method to measure fatty acids in biological samples

“…The use of DAABD-AE as a derivatisation agent was first developed by Tsukamoto et al [29], specifically for reactions with carboxylic acids and specifically for sensitive detection using ESI-MS. Use of DAABD-AE has been previously optimized [30], resulting in a convenient derivatisation process producing a highly sensitive analytical method when used in combination with LC/MS/MS. Fatty acids are known to produce a complex fragmentation when subject to ESI.…”

“…However, DAABD-AE derivatisation stabilised all the FAs analysed, producing a characteristic product ion spectrum with a consistent major fragment ion at m/z 150.5. This characteristic fragment can be explained by the dimethylaminoethylaminosulfonyl fragment within DAABD-AE [30]. Indeed a precursor ion scan for m/z 150.5 would be a good opportunity to find more potential FAs in the chromatographic run, if needed.…”

Derivatization in liquid chromatography for mass spectrometric detection

“…The detection responses of PA-derivatives were increased by 9-158 folds over the intact carboxylic acids (54). Similarly (60,61) were used for the derivatization of carboxylic acids. These reagents have an amino group as ionization moiety and a hydrophobic moiety.…”