You analyzed the C18 content of a sample of ground beef. You took 8 g of beef, a
ID: 501371 • Letter: Y
Question
You analyzed the C18 content of a sample of ground beef. You took 8 g of beef, and extracted the fatty acids into a total volume of 10 ml of solvent You took 2 ml of the fatty acid extract, and made the fatty acid methyl ester (FAME) derivatives. The final volume of the FAME sample was 50 mu l. 2 of this were injected onto the GC. The area of the C18 peak was 14753. 2 mu l of a 0.02 mg/ml C18 standard were injected in a second run. The area of the C18 peak was 18334. What was the concentration of C18 in the original tissue (in mu g/g of beef)Explanation / Answer
Peak area for standard FAME sample = 18334
Peak area for the unknown FAME sample = 14753
So,
concentration of C18 in 2 ul aliquot of unknown sample = 0.02 mg/ml x 14753/18334
= 0.0161 mg/ml
So concentration in 2 ml sample = 0.0161 mg/ml x 5o ul/2 ul
= 0.4025 mg
Concentration of C18 in 10 ml original solution = 0.4025 mg x 10/2
= 2.0125 mg
Thus, the concentration of C18 in original tissue = 2.0125 mg = 2012.5 ug/8 g
= 251.5625 ug/g
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.