Direct Determination of Volatile Analytes from Solid Samples by UV-ion Mobility Spectrometry

A simple, reliable, inexpensive sample introduction system (SIS) coupled to an ion mobility spectrometry (IMS) equipment was used for the determination of volatile analytes present in solid samples. Following minimal pretreatment, the solid sample (e.g. fish) is directly placed in a membrane unit and released analytes (trimethylamine, dimethylamine and ammonia) pass through the membrane into a nitrogen acceptor stream; finally, passing the gaseous stream trough the UV-IMS system allows the analytes to be readily determined. Volatiles are released by heating the sample at 75 degrees C for 5 min following addition of a few drops of NaOH solution. This method is quite expeditious and uses small amounts of sample. The calibration graph is linear over the concentration range 5-225 microg mL(-1). The proposed SIS-IMS method is quite repeatable (RSD<4%) and reproducible (RSD<9%). Also, it provides acceptable analyte recoveries (111+/-17%) from spiked fish samples. The results of this study testify to the potential of IMS for qualitative and quantitative analytical determinations.