The total percentage of monounsaturated fatty acids is calculated by summing the weights of all detected monounsaturated fatty acid methyl esters (FAMEs), multiplying by 100, and dividing by the total sample weight.
Understanding the Calculation
To accurately calculate the percentage of monounsaturated fatty acids in a sample, the following steps are involved:
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Identify Monounsaturated Fatty Acids: Determine which fatty acids in the sample are monounsaturated. These are fatty acids that contain one carbon-carbon double bond in their structure.
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Measure Individual Fatty Acids: The reference mentions using FAMEs (Fatty Acid Methyl Esters) for measurement, a common technique in laboratory settings. You need to measure the weight or concentration of each individual monounsaturated FAME present in the sample.
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Sum the Weights: Add the weights of all the monounsaturated FAMEs together. This provides a total weight of all the monounsaturated fatty acids detected in the sample.
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Multiply by 100: Multiply this total weight by 100. This prepares the number to be expressed as a percentage.
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Divide by Sample Weight: Divide the number obtained in the previous step by the total weight of the sample you analyzed. This expresses the total monounsaturated fatty acid weight as a percentage of the total sample.
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Formula: The calculation can be summarized using this formula:
Total % Monounsaturated Fat = [(Sum of Monounsaturated FAME Weights) * 100] / (Sample Weight)Example
Let's say you're analyzing a sample, and after performing the FAME analysis, you obtain the following results:
| Monounsaturated FAME | Weight (mg) |
|---|---|
| Oleic Acid FAME | 5.0 |
| Palmitoleic Acid FAME | 2.5 |
| Total sample weight | 100 mg |
- Sum the Weights: 5.0 mg + 2.5 mg = 7.5 mg
- Multiply by 100: 7.5 mg * 100 = 750
- Divide by Sample Weight: 750 / 100 mg = 7.5 %
Therefore, the total percentage of monounsaturated fatty acids in this sample would be 7.5%.
Practical Insights
- FAME Analysis: Gas chromatography, commonly combined with flame ionization detection (GC-FID) or mass spectrometry (GC-MS), is a method to quantify individual FAMEs in a sample.
- Sample Preparation: Sample preparation may be needed to extract and derivatize fatty acids into FAMEs which is crucial for accurate quantification.
- Units: Ensure that all weight measurements are in the same units (e.g., mg, g) before performing the calculation.
- Accuracy: The accuracy of this calculation depends on accurate FAME identification and quantification as well as accurate weight measurements.
