Chromatography Quiz No. 2

Congratulations to the winners of our last newsletter’s Chromatography Quiz: Matthew Hartz, Jamie Palmer, and Keena Njoroge from Underwriters Laboratories, Sudheer Reddy from Chemtex, and Becky Canela from Environmental Laboratory Services!

two dozen irresistible cookiesThey’ve each won, and will shortly be receiving from, two dozen irresistible cookies in five flavors: White Chocolate Hazelnut, Snickerdoodle, Peanut Butter, Oatmeal Raisin, and Chocolate Chip.

The correct answer for the modified Carbamates chromatogram: we reversed the two reagents. The OPA reagent was pumped in the Reagent One position, and the Hydrolysis reagent was pumped in the Reagent Two position. Thus 1-Naphthol, which is naturally fluorescent, appears full-sized. The other Carbamate peaks have different sizes due to their varying rate of hydrolysis – the high pH of the OPA reagent will allow for some but not complete hydrolysis prior to detection.

Chromatography Quiz: Amino Acid Analysis

Identify the error made when running the Amino Acids chromatogram below and win a prize! Simply email your answer and your full contact information to Rebecca at by March 1st in order to win. The troubleshooting answer and winner congratulations will be published in the next issue (to be anonymous, please notify Rebecca in submission).

Amino Acid Analysis of Physiological Fluids:

Pickering Standard: 011006P Native Sample Standard 0.25 µmole/mL, 10 µL injection

Pickering Column: 0354100T High Efficiency Lithium Cation-exchange Column, 4.0 x 100 mm

Normal Operating Conditions: (for reference only, condition changes may be reflected in chromatogram)

Column Temperature: 36 °C

Flow rate: 0.35 mL/min

Eluent Gradient:
Amino Acid Analysis of Physiological Fluids

Post-column conditions for amino acid analysis:
Reagent 1: Trione
Reactor 1: 130 °C, 0.5 mL
Reagent flow rate: 0.3 mL/min

Detection: UV-Vis Detector, 570nm for primary amino acids, 440nm for secondary amino acids UV-Vis Detector
Hint: Assume in this case that both Guard and Analytical column are good. For more information, search standard Amino Acid chromatogram.