For GC analysis, the substance to be analyzed must be in the gaseous form. Because of this, the analysis of many organic compounds requires that injections, columns, and detectors are kept at relatively high temperatures. However, many organic compounds are thermally unstable. In such cases, it is necessary to convert the substance to be analyzed to a more volatile derivative appropriate for GC analysis. GC derivatizing reagents such as silylating, acylating, and alkylating reagents are used for this conversion.
Meanwhile, GC has been used for the analysis of biogenic substances. This generally requires the use of various derivatizing reagents. As an example, trimethylsulfonium hydroxide 1 can easily convert fatty acids, fatty acid esters, and glycerides into their methyl esters in a single step through the pyrolysis of the corresponding sulfonium salts 2.¹⁾ The low-boiling by-product, dimethyl sulfide, does not disturb the chromatographic separation of the samples. Therefore, the method using 1 is suitable for detection not only of longer chain fatty acids but also of relatively short chain fatty acids. 1 has been successfully applied for sample preparation in the analysis of fatty acids in microorganisms and human blood serum.²⁾

■Typical Procedure
A mixture of 1mg of fatty acids is dissolved in 0.1mL toluene, and then 0.5mL trimethylsulfonium hydroxide 1 (0.2mol/L methanol solution) is added. After 30 min at room temperature, the solution is used for gas chromatography.

Five species of A5601, A5602, A5603, A5604, and A5605 are trimethylsilylating reagents prepared under strict quality control for highly sensitive analysis. They are purified and controlled so that impure substances having high boiling points, which are detrimental to the analysis, are below 20ppm per one component.