d) Using standard descriptors, mathematically define: 1) adjusted retention time; (6) 2) separation factor, also known as, relative retention; 3) retention factor; 4) relative retention.

▪ In a blood alcohol analysis by GC-FID, methanol elutes at 1 min, ethanol at 2 min, IPA at 3 min, and IS at 4 min. In the patient sample, the analyte elutes t 2 min and the IS at 8 min. What is the relative retention time and the analyte in the patient? A) methanol B) Ethanol chu C) IPA

1)Explain the peak order based on the structure of the compounds in an hold: paracetamol, acetylsalicylic acid and caffeine. 2) What influence would a change in the PH value have on the retention time and peak shape of these compounds?

Describe how to obtain a Retention Factor. What does the retention factor tell you?

An unknown sample of nail polish remover contains a mixture of acetone and ethyl acetate. If the mixture is subjected to gas chromatography, which compound would have a longer retention time?     Acetone     Ethyl acetate     Acetone and ethyl acetate would have the same retention time     Cannot be determined

Methylcyclohexane and methylcyclohexene were separated by gas chromatography in a capillary column, which showed retention times of 10.0 and 10.9 minutes, respectively. The width at base were found to be 0.76 and 0.82 minutes for methylcyclohexane and methylcyclohexene, respectively. An un-retained air peak occurs at 1.9 minutes. Calculate the column resolution (Rs) and the average retention factor (k).

▪ In a blood alcohol analysis by GC-FID, methanol elutes at 1 min, ethanol at 2 min, IPA at 3 min, and IS at 4 min. In the patient sample, the analyte elutes t 2 min and the IS at 8 min. What is the relative retention time and the analyte in the patient? ▪ A) methanol B) Ethanol ▪ C) IPA

Answer sections C, D and E in the same answer book. Section D (Chromatography) Question 8 The following data were obtained for the analysis of a mixture of compounds (A-D) by HPLC: Peak Retention time (min) | Width of peak base (min) non-retained 2.1 A 6.4 10.51 B 11.3 1.03 C 13.1 1.25 D 21.6 1.62 a) Using peak C. calculate the number of plates (N) in this column. b) For peak D, calculate the capacity factor (k'). c) For peak B and C, calculate the resolution (R).

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