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Kaixin micro test

Test probe P100-M3

Internal Standard Method for Liquor Analysis

This method is commonly used in the analysis of alcoholic beverages, where an internal standard—typically n-butyl acetate—is added to ensure accurate quantification. The internal standard helps compensate for variations in sample preparation and instrument response.

Sample Preparation:

1. Prepare 60% ethanol solution: Take 150 mL of chromatographically pure anhydrous ethanol and dilute it with purified water to a final volume of 250 mL.

2. Prepare a 2% internal standard solution: Mix 5 mL of n-butyl acetate with 250 mL of the 60% ethanol solution prepared above.

3. Sample preparation for testing: Take 10 mL of the liquor sample and add 0.2 mL of the 2% internal standard solution. This results in an internal standard concentration of 35.28 mg/100 mL in the sample.

Instrument Operation:

Use a 10 µL microsampler to inject 1 µL of the prepared sample into the gas chromatograph.

Important Note: When preparing the sample, always mix 10 mL of the liquor sample with 0.2 mL of the 2% internal standard solution. At this point, the internal standard concentration in the sample becomes 0.56 mg/100 mL.

Calibration Using N2000 Chromatography Workstation:

1. Inject 1 µL of the liquor mixed standard into the workstation. Save the file with a name like "White Wine Standard A."

Note: It's best to skip the first injection and use the second one for more consistent results.

2. Process the standard offline: Open "Liquor Standard A," select OK, then choose Map → Integration Method → Area → Internal Mark. Adjust the baseline if needed, and manually label each peak according to retention time. Identify the internal standard peak (n-butyl acetate in white wine) and enter its concentration based on the standard label. Save the calibration curve as "Liquor Calibration Curve A."

3. During sample analysis, open the saved calibration curve "A" in the online workstation. Enter the internal standard concentration and proceed with the analysis.

4. Inject 1 µL of the sample, collect data, save, and preview the results.

5. If any peaks are not identified, adjust the retention times in the component table and reprocess the data.