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A large number of volatile and semi-volatile organic compounds are present in black pepper, which are responsible for its unique odor and flavor. These compounds include aromatics, hydrocarbons, terpenes and sesquiterpenes. In order to analyze and identify these compounds, a variety of extraction and sample introduction techniques are utilized for preparation of the sample for gas chromatographic separation of the analytes and for identification via a mass spectrometer.
The purpose of this paper is to study four different GC introduction techniques and a direct mass spec technique, including (1) solvent extraction, (2) direct probe mass spectrometry, (3) direct thermal extraction (DTE), (4) dynamic headspace and (5) solid phase micro extraction (SPME). Each technique has its own advantages and disadvantages. In this study, each technique was used to analyze a sample of black pepper to compare the ease and speed of each technique, the relative sensitivity of each method and the range of volatile and semi-volatile organic compounds extracted by each method. The purpose is to develop an understanding of each technique in order to aid the selection of an appropriate method for the analysis of other samples of volatile and semi-volatile organics.
Collectively, the five techniques identified more than 100 analytes in black pepper. However, the sample size required for each technique varied, as well as the range of light volatiles and semi-volatile organic compounds detected. The direct probe mass spec technique proved to be the least specific of the methods, identifying only piperine, the major alkaloid in black pepper. The greatest sensitivity with black pepper was achieved with the solvent extraction. Purge & Trap proved the least sensitive. The DTE had the shortest preparation time—over five minutes.
Yttria coated filament at start
Yttria coated filament after 16,000 cycles