Chromatography Quiz #17

Chromatography Quiz #16 Results:

We would like to congratulate our grand prize winners of our last newsletter’s Blast from the Past Picture Quiz: Richard Dickerson from Eurofins Nutritional Analysis Center, della terra gourmet gift setNarjes Ghafoori from LA County Environmental Toxicology Laboratory, Tom Schneider from Suffolk County Water Authority, Dr. Pravish Tiwari from Cipla, Matthew Hartz from Eurofins Eaton Analytical, and Dr. Paul Levy from the Children’s Hospital at Montefiore!

They have each won and will shortly be receiving: a Della Terra Gourmet Gift Set!!  The 25-year-aged balsamic vinegar and signature extra virgin olive oil are presented elegantly in this delightful collection by the Della Terra family, and delivered courtesy of

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

The correct answer for the flashback picture:

Despite Michael’s adamant protests, the photographer insisted on prominently displaying the Trione bottles during the photo shoot for the fluorometer detector.  Seeing as how Trione is not a fluorescent reagent, this choice was almost as embarrassing as the quote “Gilson’s 121 is the best fluorometer I’ve used” boldly stated in the original advertisement.  The year this Gilson ad was published, Michael was approached (good-naturedly) by every other fluorometer manufacturer at Pittcon.

Thank you!

Pickering Labs

Chromatography Quiz #17:

Oct 1, 2014, Editor’s Note: We discovered a typo. Originally, we listed the Reactor 1 temperature at 100°C. It should be 36°C 

Identify the error made when running the Glyphosate chromatogram below and win a prize!  Simply email your answer as well as your full contact information to Rebecca at by November 1st, 2014 in order to win.  You will receive email confirmation that your submission has been received.  The troubleshooting answer and winner congratulations will be published in the next issue (to be anonymous, please notify Rebecca in submission).

Glyphosate Analysis for US EPA Method 547

Pickering Standard: 1700-0080 Glyphosate Test Mixture, 2.5 µg/mL, 10 µL injection

Pickering Column: 1954150 Cation-exchange Column for Glyphosate, 4x150mm

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

Column Temperature: 55°C

Flow rate: 0.4 mL/min

Eluant Gradient:

eluant gradient for quiz 17

Post-column conditions:

Reagent 1: Oxidizing reagent – 100 uL of 5% Sodium Hypochlorite in 950 mL of GA116

Reagent 2: 100 mg of OPA, 2 g Thiofluor™ in 950 mL of GA104

Reactor 1: 36 °C, 0.5 mL

Reactor 2: ambient. 0.1 mL

Reagent flow rates: 0.3 mL/min

Detection: Fluorometer ex 330 nm, em 465 nm

Troubleshooting Chromatogram:glyphosate troubleshooting chromatogram quiz 17

Reference Chromatogram:glyphosate reference chromatogram quiz 17

One thought on “Chromatography Quiz #17”

  1. The reactor 1 temperature is incorrect. It should be 38°C. At 100 °C the glyphosate is being broken down before detection. Only the AMPA peak is seen.

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