Short Chain Fatty Acid Headspace Analysis Optimization for GC Using Alcohol Esterification
Short chain fatty acids can be difficult to analyze by GC due to their highly acidic and polar nature affecting activity within the GC system, as well as affinity for polar solvents such as water when performing headspace analysis. Esterification is a common solution to reducing the activity of these compounds and improving detection. However, these derivatizations typically involve multiple steps in the sample preparation. In-vial derivatization using headspace analysis is investigated as a easy single step analysis method to address these issues.
In addition to the issues caused by polarity and activity, if FID detection is used, short chain acids like formic acid give exhibit low sensitivity due to the low number of C-H bonds. Esterification with alcohols is a technique used to reduce polarity and activity, and increase sensitivity. Typically, these derivatizations involve several sample preparation steps including: reaction, neutralization, extraction, and drying prior to GC analysis. Performing this in-vial derivatization by headspace analysis eliminates the need for these multiple sample preparation steps by allowing the reaction to occur in the headspace vial, then injecting directly from the headspace. In addition to the reduced sample preparation, the derivatization by headspace aids in improving the partition ratio of the analyte from the liquid phase to the headspace by decreasing the polarity of the analytes.
Within this technique there are several options in selecting the appropriate alcohol and ester to optimize analysis of the compounds of interest for different applications. Several alcohol / fatty acid combinations will be used with a USP-467 based GC method on a Shimadzu GCMS-QP2010 Ultra with an AOC-5000 Plus Autosampler to show suitability of headspace analyses of formic and acetic acid using different esterification reagents.
- Content Type:
- Paper
- Document Number:
- PO-CON1502E
- Product Type:
- Mass Spectrometry, Gas Chromatograph-Mass Spectrometry
- Keywords:
- Short Chain Fatty Acid Headspace formic acetic acid, 1-Butanol, 1-Propanol Ethanol Methano, Food and Beverages, Hydrocarbon Processing Industry (Petrochemical, Chemical), GCMS-QP2010 Ultra, AOC-5000 Plus
- Language:
- English
- File Name:
- sio215019.pdf
- File Size:
- 362kb