Category Archives: Chromatography Quiz

Chromatography Quiz #35

Chromatography Quiz #34: “What the Brij?”- RESULTS

Pickering Labs would like to congratulate all of our winners for our previous newsletter’s Chromatography Word Puzzle:

Ben Covert from New Mexico State Laboratory Division, Jim Balk from Nebraska Public Health Environmental Lab, Naomi Herrera from New Mexico Department of Health, Joy Gottlieb from New Mexico Department of Health, Josiah Hakala from Minnesota Department of Health, Jiufeng Fan from GSK, Tom Schneider from Suffolk County Water Authority, Narjes Ghafoori from Los Angeles County Public Health Laboratory.

Winners will soon receive: Amazon eGift Card! ($40.00 Value) Happy online shopping!

Congratulations to our quiz winners!

Thank you all for your submissions!

Chromatography Quiz #35 – Bad Carbamate Chromatography

Correctly answer the question below and win a prize! Simply email your answer and your full contact information to Rebecca at rlsmith@pickeringlabs.com by June 15, 2020 in order to win. You will receive email confirmation when your submission is received, and the troubleshooting answer and winner congratulations will be published in the next issue (to be anonymous, please notify Rebecca in submission).

Below you will find the method details for the Carbamate Method. What could be causing the poor peak shape and low response?

Analytical Conditions
Column:

          Carbamate Column P/N 0846250
          (250 x 4.6 mm), C8, 5 um
Flow Rate: 
          1 mL/min
Column Temperature: 
          42 ºC
Mobile Phase: 
          see Table 1

Post-column Conditions
Post-column System:
 
          Pinnacle PCX or Vector PCX
Reactor 1: 
          100 ºC, 0.5 mL
Reactor 2: 
          Ambient, 0.1 mL
Reagent 1: 
          Hydrolysis Reagent CB130 or CB130.2
Reagent 2: 
          100 mg of OPA, 2 g of Thiofluor in
          950 mL of CB910
Detection: 
          FLD, Excitation 330 nm, Emission 465 nm
Injection Volume: 
          10-20 uL

Full method details from our website here.

 

 

 

Chromatography Quiz #34

Chromatography Quiz #33: “What the Brij?”- RESULTS

Pickering Labs would like to congratulate all of our winners for our previous newsletter’s I’m not seeing any peaks! Carbamates edition Quiz: Tom Schneider from Suffolk County Water Authority, Narjes Ghafoori from LA County Environmental Toxicology Lab, and Jiufeng Fan from Glaxo Smith Kline, and Dr. David Green from Pepperdine University.

Winners will soon receive: An HP Sprocket Portable Photo Printer! A fun-size, Bluetooth enabled, cherry-tomato, portable photo printer! Just in time for those holiday selfies with family and friends! Or even better, those festive ugly sweater parties with your colleagues! We’re looking forward to sharing plenty of selfies with Onyx, our 2020 influencer!

Congratulations to our quiz winners!

Thank you all for your submissions!

 

The correct answer for the “What the Brij” Quiz:

The Brij-35 prevents quenching of large molecules. When large molecules, like the Fumonisins derivatives, quench they fold in on themselves and can lead to a reduction in fluorescent signal.

Here is a lovely answer we received from one of our quiz entries, if you want to get more in depth:
The Brij-35 is a non-ionic surfactant that, as far as I’m concerned, is a nearly miracle additive to HPLC eluent buffers to improving retention characteristics of strongly adsorbed proteins from the column surface. In my experience, it has the added […] benefit of enhancing the fluorescence intensity of the fluorescent derivative produced in the post-column reactor. The fluorescence enhancement is due to the derivative being trapped in the non-polar core of the Brij micelle. This enhancement can be extremely significant: 100s x improvement in sensitivity. It is well-established that a non-polar chemical environment improves fluorescent quantum efficiency by stabilizing the HOMO-LUMO molecular orbitals.

Chromatography Word Puzzle #34

Correctly complete the word puzzle below and win a prize! Simply email your answer and your full contact information to Rebecca at rlsmith@pickeringlabs.com by January 31st, 2020 in order to win. You will receive email confirmation when your submission is received, and the troubleshooting answer and winner congratulations will be published in the next issue (to be anonymous, please notify Rebecca in submission).

Onyx
PCX
Pinnacle
New
Sign
Paint
Derivatization
Retirement
Pickering
Laboratories
Pittcon
Cheers
Product
Testing
Solutions
Reagents
Trione
Thiofluor
OPA
Press
Release

 

 

 

 

Chromatography Quiz #33

Chromatography Quiz #32: I’m not seeing any peaks! Carbamates edition – RESULTS

Pickering Labs would like to congratulate all of our winners for our previous newsletter’s I’m not seeing any peaks! Carbamates edition Quiz: Jim Balk from Nebraska Public Health Environmental Lab, Josiah Hakala from Minnesota Department of Health, Narjes Ghafoori from LA County Environmental Toxicology Lab, Tom Schneider from Suffolk County Water Authority, and Jiufeng Fan from Glaxo Smith Kline.

Winners will soon receive: A Tile Pro Combo from Amazon.com! Tile is a tiny Bluetooth tracker and easy-to-use app that helps you find everyday items in seconds. Sleek, durable and water-resistance, the Tile Pro seamlessly pairs with your smartphone. The easiest way to find your things!

Congratulations to our quiz winners!

Thank you all for your submissions! 

 

The correct answers for the “I’m not seeing any peaks!” Carbamates edition quiz:

The reactor temperature was set too low. In normal operation, the reactor temperature should be set to 100 °C for proper post-column reaction completion. The incomplete reaction will give you low response for all analytes except Carbaryl and 1-Naphthol. Carbaryl becomes 1-Naphthol after the first step in the post-column reaction and 1-Naphthol is naturally fluorescent and does not require the OPA reaction.

Chromatography Quiz 33 – What the Brij?!?

Correctly answer the question below and win a prize!  Simply email your answer and your full contact information to Rebecca at rlsmith@pickeringlabs.com by November 1, 2019 in order to win.  You will receive email confirmation when your submission is received, and the troubleshooting answer and winner congratulations will be published in the next issue (to be anonymous, please notify Rebecca in submission). 

Below you will find the method details for the Fumonisins method. What is the purpose of adding 30% Brij to the post-column derivatizing reagent?

(Full method abstract(s) available on our website.)

 

 

 

Chromatography Quiz #32

Chromatography Quiz #31: Glyphosate Doublet Peak – RESULTS

Pickering Labs would like to congratulate all of our winners for our previous newsletter’s Glyphosate Doublet Quiz: Jim Balk from Nebraska Public Health Environmental Laboratory, Tom Schneider from Suffolk County Water Authority, Narjes Ghafoori from LA County Public Health Laboratories, and Jiufeng Fan from Glaxo Smith Kline.

Winners will soon receive: An All-New Amazon Kindle Whitepaper!!!  The thinnest, lightest Kindle Whitepaper yet, this waterproof e-reader is sure to help our winners unwind with some beachside or poolside relaxation this summer!  Happy reading!

Congratulations to our quiz winners!

Thank you all for your submissions! 

 

 

    .

The correct answers for the Glyphosate Doublet Peak quiz:

The Glyphosate ‘doublet’ is caused by injecting a sample at basic pH.  An improperly buffered sample extract at a large injection volume will not mix with the mobile phase sufficiently to create the acidic pH necessary for Glyphosate to be at the proper single charge state, impacting the interaction between Glyphosate and the active sites on the column resin.  Adding a couple drops of RestoreTM (pH 1.3) to the sample before injection will eliminate the ‘doublet’ and return proper peak shape. 

Chromatography Quiz #32 – I’m not seeing any peaks, Carbamates edition!

Identify the error made when running the Carbamates chromatogram below and win a prize! Simply email your answer and your full contact information to Rebecca at rlsmith@pickeringlabs.com by August 30, 2019 in order to win.  You will receive email confirmation when your submission is received, and the troubleshooting answer and winner congratulations will be published in the next issue (to be anonymous, please notify Rebecca in submission). 

Good Chromatogram
HPLC Flow Rate: 1.0ml/min
Reagent Flow Rate: 0.3ml/min
Column Temp: 42C
Reactor Temp: 100C

Elution order:

Bad Chromatogram
HPLC Flow Rate: 1.0ml/min
Reagent Flow Rate: 0.3ml/min
Column Temp: 42C
Reactor Temp: 36C

 

 

 

 

Chromatography Quiz #30

Chromatography Quiz #29: Amino Acids Elevated Baseline – RESULTS

Pickering Labs would like to congratulate all of our winners for our previous newsletter’s Elevated Baseline Amino Acids Chromatogram: Tom Schneider from Suffolk County Water Authority, Narjes Ghafoori from LA County Environmental Toxicology Lab, and Dr. David Green from Pepperdine University!

Winners will soon receive: A Harvest Bundle of Gifts from www.HarryandDavid.com!

This bountiful harvest bundle includes: creamy Pumpkin Cheesecake, a beautiful Autumn Garden Party plant gift, and a Pumpkin-Shaped Gift Basket which features juicy pears, pumpkin bars, cranberry relish, and much more. It’s the perfect way to celebrate the changing of the seasons. Best of all, bundle gift items are sent individually to make the celebration last a little longer!

Congratulations to our quiz winners and we hope they look forward to receiving their gifts next week!

Thank you all for your submissions!
  
  
    
   

The correct answers for the Elevated Baseline Amino Acids Chromatogram are as follows:

The shift on the baseline is called an ammonia plateau and it is due to the presence of low-level amines and ammonia in the buffers. These compounds accumulate on the column during equilibration time and come out during the gradient in a form of a plateau. Since the buffers have low pH, these compounds are unavoidable but care should be taken to avoid excessive contamination that can cause the plateau to be too high. Amines are present even in the air and get dissolved in buffers as time goes by.

The issue usually comes from buffer A. Try and replace with a new lot if possible.

Below are some tips on how to minimize any potential problems:

  • Remove all filters from the ends of HPLC lines that go into the buffer bottles. All our products are filtered before bottling and these in-line filters only drag contamination from one bottle to another.
  • Replace open buffers on the instrument at least every two weeks. If you don’t use the full bottle in 2 weeks, pour half of the bottle into a clean glass bottle to put on the instrument and tightly cap the remaining portion to keep until future use.
  • Don’t flush column with water, use only Column Regenerant for cleaning the column.
  • Don’t use the first injection of the sequence for calculations since it usually has a different profile due to differences in equilibration time.
  • Program the needle wash between the runs to avoid carry over.
  • If you see unexpected peaks on your blank or other chromatograms make a fresh vial of the solution and run again to confirm the problem. Also run “No Injection” to see if the peaks are coming from the injected sample of from the baseline.
  • Flush HPLC periodically with 100% water, then 100 % methanol, then 100 % water with no column attached (!!!) to keep the lines clean.

Chromatography Quiz #30 – Aflatoxins Analysis, Decreased Signal:

Simply email your answer as well as your full contact information to Rebecca at rlsmith@pickeringlabs.com by December 21, 2018 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).

Aflatoxin analysis by photochemical derivatization is achieved with the parameters listed below:

Analytical Column: Mycotox Column, C18 4.6x250mm
HPLC Eluent: Sodium Phosphate buffer PN 1700-1108/Methanol/Acetonitrile (57/28/15)
Flow Rate: 1 ml/min
FLD: Excitation 365nm, Emission 430nm
UVE Photochemical reactor with 254nm UV light: 1.0ml knitted reaction coil.

 

What could contribute to a decrease in signal?

 

 

 

 

 

 

Chromatography Quiz #29

Chromatography Quiz #28: 35th Anniversary Word Puzzle – Results

Pickering Labs would like to congratulate all of our winners for our previous newsletter’s 35th Anniversary Word Puzzle: Jim Balk from Nebraska DHHS Public Health Environmental Laboratory, Tom Schneider from Suffolk County Water Authority, Karissa Scroggins from North Coast Laboratories, Narjes Ghafoori from LA County Environmental Toxicology Lab, Joy Gottlieb from New Mexico Department of Health Scientific Lab Division, Hossein Hajipour from Texas Dept. of State Health Services Laboratories, and Widchuda Meeim from Thailand Bureau of Quality Control of Livestock Products.

Winners will soon receive a Packing Organizer Set from the Container Store! This colorful set of 6 packing cubes are durable and clearly labeled to help you organize your suitcase! Just in time as you plan for those summer getaways!

Congratulations to our quiz winners and happy packing!

Thank you all for your submissions! 


             

The correct answers for the Anniversary Word Puzzle are as follows:

Chromatography Quiz #29 – Amino Acids Elevated Baseline:

Simply email your answer as well as your full contact information to Rebecca at rlsmith@pickeringlabs.com by July 15, 2018 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). 

Maroon: Good chromatogram

Blue: Elevated baseline

What could be contributing to the elevated baseline?

   

   

   

Chromatography Quiz #27: Only AMPA

Chromatography Quiz #26: Shifting Retention Times – Carbamates — Results

Pickering Labs would like to congratulate the winners of our last newsletter’s Shifting Retention Times–Carbamates Quiz: David Green from Pepperdine University, Jeff Fan from Cumberland Valley Analytical Services, Karissa Scroggins from North Coast Laboratories, Jim Balk from Nebraska DHHS Public Health Environmental Laboratory, Narjes Ghafoori from LA County Agricultural Commissioner Weights & Measure Environmental Toxicology Lab, Tom Schneider from Suffolk County Water Authority, and Ms. Widchuda Meeim from Thailand Bureau of Quality Control of Livestock Products.

They have each won and will shortly receive a Williams Sonoma BBQ Tools Set! Included in a stainless-steel case for easy storage, these sleek grilling tools are perfect for those upcoming summer cookouts!

Congrats to our quiz winners and happy grilling!

Thank you all for your submissions! 

The correct answer to the Sifting Retention Times – Carbamate Quiz:

Leaking proportioning valve. The leaking proportioning valve improperly mixed the method gradient and didn’t have enough methanol which caused the analytes to elute late.

Chromatography Quiz #27: Only AMPA

What is causing the bad chromatography in the example below?  Simply email your answer as well as your full contact information to Rebecca at rlsmith@pickeringlabs.com by September 1, 2017 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). 

Glyphosate Analysis – Only AMPA

Pinnacle or Vector PCX post-column instrument is being used, in a traditional HPLC setup as recommended by Pickering Laboratories. The quiz question: what is causing Glyphosate to disappear?  

Post-column conditions for carbamates analysis:

Reagent 1: GA116
Reagent 2: o-Phthalaldehyde and Thiofluor in GA104
Reactor: 36 °C, 0.5 mL
Reagent flow rate: 0.3 mL/min
Injection volume: 10uL

FLD Settings:

λex 330 nm
λem 465 nm

HPLC Flowrate: 0.4 mL/min
Column Temperature: 55°C


 

Good Chromatogram

Glyphosate Test Mix, 2.5ppm, 10µl Injection

Bad Chromatogram only shows AMPA peak. No Glyphosate peak can be detected.

Glyphosate Test Mix, 2.5ppm, 10µl Injection