Chromatography Quiz No.14

Chromatography Quiz #13 Results

We would like to congratulate our grand prize winners of our last newsletter’s Carbamate Analysis Chromatography Quiz: Irene Taylor from Orange County Utilities, Jim Balk from DHHS Public Health Environmental Laboratory, Narjes Ghafoori from LA County Environmental Toxicology Laboratory, Helene Lachance from Shur-Gain Nutreco, and Jamie Palmer and Matthew Hartz from Underwriters Laboratories!!!

laser chess 1They have each won and will be receiving: a Laser Board Game from laser chess 2Sharper Image!  (This strategy-based board game is similar to chess and features an 80-square Egyptian themed grid.  The goal is to protect your game pieces while eliminating your opponent’s by bouncing eye-safe lasers at them through the maze of mirrors you’ve constructed.)

We would like to thank all of you for your submissions!

The correct answer for the modified Carbamate chromatogram: Reagent #2 (CB910, OPA, and Thiofluor) was partially oxidized.  The peak heights of Carbaryl and 1-Naphthol have significant diagnostic importance in regard to the OPA reagent system. Since 1-Naphthol naturally fluoresces, we can eliminate the fluorescence detector as the problem.  Though smaller peak sizes can reflect problems with Reagent #1, since the Carbaryl peak is full-sized, we can deduce that hydrolysis has occurred (Carbaryl naturally fluoresces after hydrolysis).

Particularly astute observation yields additional details about our troubleshooting chromatogram – slightly shifting retention times towards the end of the run could indicate a problem with HPLC hardware, such as a proportioning valve.

Thank you!

Pickering Labs

 Chromatography Quiz #14:

Complete the cross word puzzle below and win a prize!  Simply email your answer (copy of completed puzzle or list answers with clues) as well as your full contact information to Rebecca at by December 15, 2013 in order to win.  You will receive email confirmation that your submission has been received.  The answer to the puzzle and winner congratulations will be published in the next issue (to be anonymous, please notify Rebecca in submission).

Carbamate/Glyphosate Analysis: Cross Word Puzzle