Analysis of Ethanol in Moonshine
Analysis of Ethanol in Moonshine| Using the GC-MS| Jennifer Greene| ————————————————- 4 May 2012 ————————————————- 4 May 2012 Introduction: In this experiment gas chromatography is applied to separate the water-ethanol mixture. This method is often used in the determination of alcohol in blood or urine. One obvious application is when law enforcement agencies need to determine whether or not someone is inebriated. In these cases, high sensitivity is required since 0. 1% blood alcohol content is considered to be legally intoxicated in most states.
Our own determination will deal with higher concentrations (up to 25% by volume) which are more typical of alcohol levels found in many alcoholic beverages.
Chromatography is a physical method of separation in which the components to be separated are distributed between two phases, one of the phases constituting a stationary bed of large surface area, the other being a fluid that percolates through or along the stationary bed Gas chromatography (GC) is a powerful and widely used tool for the separation, identification and quantitation of components in a mixture.
In this technique, a sample is converted to the vapor state and a flowing stream of carrier gas (often helium or nitrogen) sweeps the sample into a thermally-controlled column. In the case of gas-liquid chromatography, the column is usually packed with solid particles that are coated with a non-volatile liquid, referred to as the stationary phase. As the sample mixture moves through the column, sample components that interact strongly with the stationary phase spend more time in the stationary phase vs. the moving gas phase and thus require more time to move through the column.
The goal of GC is to separate and detect components of a mixture as efficiently as possible and it is thus desirable to have a measure of the efficiency of a given chromatographic column.
One common way to express column efficiency is by calculating the height equivalent to a theoretical plate (HETP) which is the length of the column divided by the number of theoretical plates. HETP = l/n The number of theoretical plates (n) of a column with respect to a particular compound can be found using the following equation: N = 16(tr/w)2 = 5. 55(tr/w1/2)2
Where w is the peak width measured in the same units as tr and w1/2 is the peak width measured at half of the peak height. Materials: GC-MS with database| Vials with lids| Cherry moonshine| Disposable pipettes| Ethanol 100%| | Procedure: 1. Set up procedure to: Set “Detector A” On (Thermal Conductivity Detector) Packed Column Head Pressure: 30 psi Column: Carbowax 20M, 1/8″ OD, length = 6 feet Oven Temperature: 110°C Detector Temperature: 150°C Injection Temperature: 150°C 2. With the disposable pipette fill separate vials with the cherry moonshine and pure ethanol.
. Run the procedure then define the ethanol peak with three additional peaks. This is the chromatograph for Cherry Moonshine. This is the chromatograph for Cherry Moonshine. Data: The blue arrows are pointing to the ethanol peak.
The blue arrows are pointing to the ethanol peak. Conclusion: Chromatography is a physical method of separation in which the components to be separated are distributed between two phases, one of the phases constituting a stationary bed of large surface area, the other being a fluid that percolates through or along the stationary bed.
Gas chromatography (GC) is a powerful and widely used tool for the separation, identification and quantitation of components in a mixture. In this technique, a sample is converted to the vapor state and a flowing stream of carrier gas (often helium or nitrogen) sweeps the sample into a thermally-controlled column. In the case of gas-liquid chromatography, the column is usually packed with solid particles that are coated with a non-volatile liquid, referred to as the stationary phase.
As the sample mixture moves through the column, sample components that interact strongly with the stationary phase spend more time in the stationary phase vs. the moving gas phase and thus require more time to move through the column. This experiment demonstrated how the analysis of an unknown substance can be determined from the separate peaks. If you select an individual peak on the chromatograph, the database will bring up possible matches of the compound.
You would need to look at the mass spectrograph of that peak to see if it matches the compound of interest.
If it does, then you have confirmed one compound that is present in the substance. If it is not a match, continue to search the database until you confirm the peak’s identity. From this experiment, the peak for ethanol was not determined using the mass spectrograph of the gas chromatography; however, we ran pure ethanol on the GC-MS and compared the two chromatographs to determine the ethanol peak.
