The peroxisome is a cellular organelle that plays an important role in a number of functions, including the beta-oxidation of very long chain fatty acids (VLCFA). Peroxisomal disorders are characterized by impaired, reduced or total absence of peroxisomes in cells, which can result in the accumulation of VLCFAs, such as tetracosanoic and hexacosanoic acids, in plasma. Some variants of these disorders are characterized by the accumulation of phytanic acid.
Up to now, quantification of VLCFA has been done by gas chromatography (GC) or gas chromatography-mass spectrometry (GC-MS). These methods are often time-consuming and quite demanding in terms of sample preparation. Moreover, due to the lack of appropriate standards, quantification of VLCFAs is frequently based only on the calculation of significant ratios such as C 26:0/C 22:0 and C 24:0/C 22:0.
Recently, D.W.Johnson proposed a new procedure for the rapid analysis of VLCFAs based on tandem mass spectrometry(1). This approach targets all the VLCFA forms, i.e. free forms of VLCFA as well as forms that are incorporated into phospholipids and ester forms. The method does not, however, distinguish isobaric forms, because the measurements are done in flow-injection mode.
This application note describes a method for the quantitation of VLCFAs, using a simple and robust LC/MS/MS hardware configuration. The method includes a chromatographic step and a non-isotopicallylabelled internal standard. The resulting approach has the potential of greater specificity, lower detection limits, and a broader dynamic range than previously suggested strategies, for a wide variety of fatty acids.
Sensitive and selective Multiple Reaction Monitoring (MRM) scan function for linear quantitative analysis with wide dynamic range
Patented LINAC c