The applicability and utility of the microwave sustained helium emission detector (MED) as a gas chromatographic detector can be greatly increased by utilizing elemental tagging derivatization of various functional groups such as alcohols, acids, amines, phenols or thiols. Dual element acetylation tagging can, for example, be accomplished with chlorodifluoroacetic anhydride, and acetylated amines are readily detected via their chlorine and fluorine responses. The helium MED provides an absolute response to a given element which is not generally affected by its molecular environment. A “dual homolog derivatization” concept is described utilizing this absolute response characteristic. Dual derivatization tagging enhances both the qualitative and quantitative aspects of the analysis by providing elemental tags for the derivatizable components of interest and by multiplying the number of data points used for quantitation.