UVM Theses and Dissertations
Format:
Print
Author:
Gakpe, Edward A.
Dept./Program:
Chemistry
Year:
2013
Degree:
MS
Abstract:
Methanol is toxic and lethal when ingested in large amounts. Methanol is also present in a variety of foods and beverages in low amounts, but can be of higher concentration in distilled spirits. Hence, there is a need for a method for its measurement with good sensitivity. We describe the development of a positive chemical ionization (PCI) gas chromatography-mass spectrometry (GC-MS) method for measuring methanol and ethanol levels in fermented and distilled alcoholic beverage products. We used ²H₃-ethanol as the internal standard for methanol quantification and ²H₃-ethanol as the internal standard for ethanol measurement. The internal standards mimic accurately the analytes (methanol and ethanol).
The GC-MS method is also highly specific to the ions being measured for methanol and ethanol. We used a high polarity ZB-WAXplus capillary column to separate methanol from ethanol and water on the GC-MS. Our method has also been applied to soft drinks containing aspartame for methanol quantification. Our GC-MS method requires less than 0.5 ml of sample for methanol measurements and 10 [mu]1 of sample for ethanol measurements. The method also allows for direct sample injection without sample pretreatment.
Our method is specific for monitoring selected molecular ions that elute at a specific time. Our assay is sensitive and has a limit of quantification of 0.2 [mu]g/ml for methanol and 0.1%, v/v (0.8 mg/ml) for ethanol. The precision (coefficient of variation, CV) of our assay for quantifying high methanol content samples is 1.5%, for low methanol content samples is 3.3%, and for ethanol in the samples is 5.3%.
The GC-MS method is also highly specific to the ions being measured for methanol and ethanol. We used a high polarity ZB-WAXplus capillary column to separate methanol from ethanol and water on the GC-MS. Our method has also been applied to soft drinks containing aspartame for methanol quantification. Our GC-MS method requires less than 0.5 ml of sample for methanol measurements and 10 [mu]1 of sample for ethanol measurements. The method also allows for direct sample injection without sample pretreatment.
Our method is specific for monitoring selected molecular ions that elute at a specific time. Our assay is sensitive and has a limit of quantification of 0.2 [mu]g/ml for methanol and 0.1%, v/v (0.8 mg/ml) for ethanol. The precision (coefficient of variation, CV) of our assay for quantifying high methanol content samples is 1.5%, for low methanol content samples is 3.3%, and for ethanol in the samples is 5.3%.