Amines may be produced through the degradation of biological material, most notably proteins. As a class of compounds, they generally exhibit unpleasant odors and relatively low odor thresholds. Unfortunately, the measurement of low level amines is complicated by their strongly basic
properties, which can cause high adsorption losses upon contact with active surfaces in air sampling containers and analytical equipment. A method has been developed for the detection and quantitation of trace level, low molecular weight amines in air and gas samples using solid phase microextraction
(SPME) techniques. The sampling procedure involves drawing a known volume of ambient air or gas through an impinger system containing a dilute sulfuric acid absorbent solution. After sample collection, a small aliquot of the impinger solution is placed in a small septum-capped vial. Sodium
hydroxide is added to the vial until the solution becomes moderately basic, allowing free amines to be released into the headspace region above the solution. A SPME fiber is inserted into the solution headspace region and kept there for a set amount of time in order to extract the volatile
amines. The fiber is then withdrawn from the vial and inserted into a hot gas chromatograph (GC) injection port. There, the amines are thermally desorbed from the fiber and separated on specially deactivated analytical columns. A nitrogen phosphorous detector (NPD) is used for measurement
of the amine concentrations. Methods involving the direct GC injection of basic impinger solutions were also evaluated, but generally gave lower sensitivity, poor chromatographic separations, and increased column contamination. Utilizing a CP-PoraPlot Amine® column, the amines analyzed
by this method include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, N-ethylmethylamine, N-propylamine, iso-propylamine, tert-butylamine, sec-butylamine, iso-butylamine, N-butylamine, and pyrrole. For typical
impinger sampling conditions, detection limits were in the high pptr v/v to low ppb v/v range, roughly corresponding to the odor detection threshold range for many of the amines.
Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed. WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access.