Chromatography Quiz #22

Chromatography Quiz #21 Results

Pickering Labs would like to congratulate our winners of our last newsletter’s AAA quiz: Helene Lachance from Shur-Gain Nutreco, Joy Gottlieb from New Mexico Department of Health Scientific Lab Division, Tom Schneider from Suffolk County Water Authority, and Narjes Ghafoori from LA County Environmental Toxicology Lab!   

cq_21They have each won and will shortly be receiving: A fabulous Godiva gift basket from!   “It’s easy to celebrate with this chocolate collection…!

We hope our quiz winners enjoy this infusion of February cheer.

Thank you all for your submissions!  


The correct answer to the Amino Acid Analysis quiz: 

Although we gave credit for answers indicating Trione oxidation, the correct answer was actually a reduced reactor temperature!  When the reaction was performed inside the heated reactor at a temperature of 120°C rather than 130°C, the peak areas are approximately 2/3 of their original size.  Similar results could also be expected with reduced dwell times or reactor volumes.

Chromatography Quiz #22: Carbamates Analysis

Identify the error made when running the Carbamates chromatogram below and win a prize!  Simply email your answer as well as your full contact information to Rebecca at by March 15th, 2016 in order to win.  You will receive email confirmation that your submission has been received.  The answer to the quiz and winner congratulations will be published in the next issue (to be anonymous, please notify Rebecca in submission).   

Carbamate Analysis for US EPA Method 531.1
Pinnacle PCX post-column instrument (two-pump) is being used in a traditional HPLC setup as recommended by Pickering Laboratories.  The reference chromatogram and troubleshooting chromatogram are both shown.  Can you identify the error made when running the chromatogram?

Pickering Standard: 1700-0063 Carbamate Test Mixture, 2.5 µg/mL, 10 µL injection

Pickering Column: 0846250 Carbamate Column, C8, 4.6 x 250 mm

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

Column Temperature: 42 °C

Flow rate: 1 mL/min

Eluent Gradient:








85 15


25 75


0 100


0 100
49.1 85 15
57 85 15


Post-column conditions:

Reagent 1: Hydrolysis reagent CB130

Reagent 2: 100 mg of OPA, 2 g Thiofluor in 950 mL of CB910

Reactor 1: 100 °C, 0.5 mL

Reactor 2: ambient. 0.1 mL

Reagent flow rates: 0.3 mL/min

Detection: Fluorometer λex 330 nm, λem 465 nm

Troubleshooting Chromatogram:


Reference Chromatogram: