The analysis of biogenic amines in the thoracic nervous system of the locust, Schistocerca gregaria, by gas-chromatography negative ion chemical ionization mass spectrometry (GC-NICIMS)

Abstract

Biogenic amines in single ventral thoracic nerve cords of the locust, Schistocerca gregaria, have been identified and quantified by an extraction-derivatization procedure involving their reaction with ditrifluoromethylbenzoyl chloride (DTFMB) in the aqueous phase followed by extraction into an organic solvent, hydrolysis of phenolic esters and conversion of free hydroxyl groups to trimethylsilyl ethers. Subsequent analysis of these DTFMB-TMS derivatives by GC-NICIMS revealed that the molecular ion carried most (> 60%) of the ion current which made the method highly specific and gave a limit of detection below the picogram level. This publication establishes unequivocally that the principal amines in locust ventral thoracic nerve cord are p-tyramine, p-octopamine, dopamine and noradrenaline. 5-Hydroxytryptamine was determined using a previously published GC-NICIMS technique (Markey et al., Biomed. Mass Spectromet. 7, 301–304, 1981).