Dimethylaminoethyl esters for trace, rapid analysis of fatty acids by electrospray tandem mass spectrometry

Abstract

The development of a new derivative, the dimethylaminoethyl ester, for the analysis of fatty acids by electrospray tandem mass spectrometry is described. Qualitative and quantitative analyses of long to very long chain fatty acids in plasma, blood, urine and wax were performed. Branched chain, unsaturated, dicarboxylic, hydroxy, amino and keto acids were studied. The quantitative analysis method using the new derivative is simple, rapid and precise with small sample size. It has good potential as a screening method for biologically important fatty acids. Copyright 1999 John Wiley & Sons, Ltd.

Liquid chromatography-tandem mass spectrometry applications in endocrinology

“…Derivatization was shown to be useful to increase the molecular weight of a precursor ion and to improve ionization efficiency (Chace et al, 1993;Johnson, 1999Johnson, , 2001Gao, Zhang, & Karnes, 2005;Kushnir et al, 2006a,b), to eliminate the interferences (Kushnir et al, 2001) and to change the polarity of the detection (Johnson 1999;Kushnir et al, 2001), to improve the fragmentation patterns and to reduce the matrix effects (Johnson, 1999;Kushnir et al, 2001). Derivatization proved to be useful in the high-throughput screening of acylcarnitines (Millington et al, 1989), amino acids (Chace et al, 1993), and organic acids (Johnson, 1999); high-throughput quantitative analysis of methylmalonic acid (MMA) (Kushnir et al, 2001;Kushnir, Rockwood, & Nelson, 2004); to reduce the sample volume required for the analysis of endogenous steroids (Kushnir et al, 2006a(Kushnir et al, ,b, 2008; and in cases when very limited samples are available for analysis (Kushnir et al, 2009).…”

“…Derivatization proved to be useful in the high-throughput screening of acylcarnitines (Millington et al, 1989), amino acids (Chace et al, 1993), and organic acids (Johnson, 1999); high-throughput quantitative analysis of methylmalonic acid (MMA) (Kushnir et al, 2001;Kushnir, Rockwood, & Nelson, 2004); to reduce the sample volume required for the analysis of endogenous steroids (Kushnir et al, 2006a(Kushnir et al, ,b, 2008; and in cases when very limited samples are available for analysis (Kushnir et al, 2009). …”

Matrix effects: the Achilles heel of quantitative high-performance liquid chromatography–electrospray–tandem mass spectrometry

“…It is now accepted that HPLC-ESI-MS/MS is the method of choice for screening for inherited metabolic disorders [10], but it can be expected that many more applications will follow. While many biochemical markers such as steroids, fatty acids, amino acids, catecholamines, and thyroxine have been measured by this analytical technique [11][12][13][14][15]. Specific examples of clinical laboratories applying HPLC-ESI-MS/MS to drug quantification are for the therapeutic drug monitoring of immunosuppressant drugs [16] and protease inhibitors [17], and toxicological investigations [18,19].…”

Reconstituted high-density lipoprotein infusion modulates fatty acid metabolism in patients with type 2 diabetes mellitus

“…Total measured lipids of each class were calculated by summing the individual lipid species. NEFA was extracted using a scaled-down Dole extraction ( 39 ), followed by derivatization to its corresponding N,N,Ntrimethylethylenediamine (TMEN) iodide salt by a method similar to that described by Johnson for the trimethylaminoethylester iodide salt ( 40,41 ). Briefl y, extracted fatty acids (10 µl plasma) containing 250 pmol of FA 17:0-d3 (CDN Isotopes) were treated successively with thionylchloride (20 µl, 0.2 M in dichloromethane, 10 min RT) N,N-dimethylethyenediamine (60 µl, 10 min RT), and methyliodide (60 µl, 50% v/v in methanol, 2 min RT) with each reagent/solvent removed under a stream of nitrogen prior to the addition of the next.…”