Category Archives: Chromatography

carbamate, Chromatography, Chromatography Quiz

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.)

 

 

 

AMPA, Chromatography, Chromatography Quiz, Uncategorized

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

 

Chromatography, Chromatography Quiz, Uncategorized

Chromatography Quiz #25

Chromatography Quiz #24 Results

1-fit-bitPickering Labs would like to congratulate the winners of our last newsletter’s Glyphosate Quiz: David Green from Pepperdine University Natural Science Division, Jim Balk from the DHHS Public Health Environmental Laboratory, Narjes Ghafoori from LA County Environmental Toxicology Lab, Karissa Scroggins from North Coast Laboratories, Helene Lachance from Shur-Gain Nutreco, Tom Schneider from Suffolk County Water Authority, and Irene Taylor from Orange County Utilities Water Division Laboratory! 

They have each won and will shortly be receiving a: Fitbit Flex 2 wristband tracker! An ultra-slim, light-weight wristband for daily activity and sleep tracking! This wearable tech goody is also water and swim-proof! Happy tracking to our Quiz Winners!

Thank you all for your submissions!    

 

  

The correct answer to the Polyether Antibiotics Analysis quiz:

The correct answer to the Glyphosate Analysis Quiz was: we injected a sample at the wrong pH. The samples should be at pH 2 for Glyphosate analysis, especially at high injection volumes. A neutral pH sample can cause peak broadening and sometimes the Glyphosate peak elutes as a doublet. The later eluting AMPA peak is less affected by sample pH problems.

We received really great submissions on this quiz from our contestants that included other reasons for misshapen Glyphosate peaks, so we are included for a couple here for additional troubleshooting background/advice!  Nice work everyone!

From one submission, we learn that metal contamination can also affect peak shape: Glyphosate is a pretty good chelating agent through the phosphate end so contamination with transition metals, especially iron, will affect the peak shape of Glyphosate and AMPA with Glyphosate being the first peak impacted.  In the case of metal contamination Pickering recommends flushing the column with Restore, the solution formulated to remove transition metals and to bring the column back to “peak” performance.

Another scientist has pointed out a different common reason for Glyphosate peak shape problems and retention time shift: Extra-column band broadening. Extra-column band broadening will affect more dramatically the early eluting glyphosate peak. If all the peaks are affected in the chromatogram, it would suggest that a problem is related to either the system or the column. As this is not the case here and only the early eluting peaks are affected, it suggests that the problem could lay with the fluid path – fittings, void in guards or sample/mobile phase solvent, etc.  It is always a good idea to make sure all the tubing connections are made correctly; there are no bubbles in the lines or guard column and the injector stator/rotor seal are not worn or defective.

Chromatography Quiz #25: B@$eL!nE Noise!

What is causing the baseline noise in the chromatogram below?  Simply email your answer as well as your full contact information to Rebecca at rlsmith@pickeringlabs.com by January 1st, 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). 

Amino Acid Analysis – Baseline Noise

Pinnacle PCX post-column instrument is being used, in a traditional HPLC setup as recommended by Pickering Laboratories. The quiz question: what is causing the baseline noise? 

Post-column conditions for Lithium Amino Acid analysis:
Reagent 1: Trione
Reactor: 130 °C, 0.5 mL
Reagent flow rate: 0.3 mL/min
Injection volume: 10uL

DAD Settings:
Signal = 570nm
Reference = Off

HPLC Flowrate: 0.35mL/min
Column Temperature: 37 °C

   

1-quiz-25

 

 

 

 

 

Chromatography, Chromatography Quiz

Chromatography Quiz #23

1 Comment

Chromatography Quiz #22 Results

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

contest-prizeThey have each won and will shortly be receiving: a Picnic Basket Gift Tin from Harry & David!  From their webpage: Celebrate the season with this gourmet gift basket, featuring a wonderful assortment of snacks, including fruit, meat, cheese, and crackers perfect for picnics and lunches in the park. In addition to our remarkably juicy Royal Verano Pears, we're offering a range of picnic delights, like white cheddar cheese, hickory smoked summer sausage, peanut butter pretzels, sweet raspberry galettes, and more. Packaged in an exclusively designed picnic-ready tin, this gift is ready to help you make any occasion a special one

We hope our quiz winners enjoy their prizes and the springtime weather!

 

Thank you all for your submissions!  

 


The correct answer to the Carbamates Analysis quiz: 

The answer for last quarter’s quiz was: incorrectly prepared reagent.  We prepared our “hydrolysis reagent” with CB910 instead of CB130.  The hydrolysis reagent CB130 is at a pH of 12.5, which is much more basic than our OPA diluent CB910 at a pH of 9.1.  From our Carbamates Manual: The separated carbamates are first saponified by NaOH at 100°C to release an alcohol, carbonate, and methylamine.  In the second post-column reaction, methylamine reacts with OPA and Thiofluor to form the highly fluorescent derivative.  So, if there is insufficient NaOH present for the first reaction, some of the carbamates do not fully hydrolyze.  

Chromatography Quiz #23: Polyether Antibiotics Analysis

What caused the noise for the blue signal in the troubleshooting chromatogram below?  Simply email your multiple choice answer as well as your full contact information to Rebecca at rlsmith@pickeringlabs.com by July 1st, 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). 

Polyether Antibiotics Analysis

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.

Narasin Standard: 2.5 µg/mL, 100uL injection

Pickering Column: 2381750, Polyether Column, C18, 4.6x250mm

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

Column Temperature: 40 °C
Flow rate: 0.7 mL/min
Isocratic: 90% Methanol, 10% of 5% Acetic Acid solution in water

Post-column conditions:

Reagent 1: Concentrated Sulfuric Acid / Methanol (4:96 v/v)
Reagent 2: 60g of Vanillin in 950mL of Methanol
Reactor 1: Ambient, 0.1mL
Reactor 2: 90 °C, 1.4mL
Reagent flow rates: 0.3 mL/min

Black (Reference) Signal:

DAD detector 520nm with bandwidth of 4nm
No reference wavelength
Sampling rate >0.10min (2.0 S response time) (2.5Hz)

Blue (Troubleshooting) Signal:

DAD detector 520nm with bandwidth of 4nm
Reference wavelength of 360nm
Sampling rate >0.05 min (1.0 S response time) (5HZ)
Can you identify the error made when running the chromatogram?

Multiple Choices:

A) Bad lamp
B) Reference Wavelength
C) Sampling rate
D) All of the above

Troubleshooting:

quiz-chart

 

 

 

 

Chromatography, Chromatography Quiz

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 www.winecountrygiftbaskets.com!   “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 rlsmith@pickeringlabs.com 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:

TIME (MIN)

WATER

MEOH, %

0

85

15

1

85 15

44

25 75

44.1

0 100

49

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:

cq-22-1

Reference Chromatogram:

cq-22-2

 

 

 

 

Chromatography, Chromatography Quiz

Chromatography Quiz #19

Chromatography Quiz #18 Results

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

q19-1They have each won and will shortly be receiving:
a Polaroid Cube Action Flash Memory Digital Camcorder
(POLC3X) with HD-1080p from Target.com!!

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

The correct answer (click to enlarge):

q19-2

Thank you!
Pickering Labs

Chromatography Quiz #19: Glyphosate Analysis High Pressure Troubleshooting!

Answer the three high pressure questions correctly and win a prize! Simply email your answer as well as your full contact information to Rebecca at rlsmith@pickeringlabs.com by May 15th, 2015 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).

Glyphosate Analysis for US EPA Method 547

HPLC running with Pinnacle PCX dual-pump system. Assume normal operating conditions (with respect to flow rates, temperatures, etc.).

Glyphosate Analysis normal pressures

Column Pressure Reagent 1 Pressure Reagent 2 Pressure
90 bar 230 psi 130 psi

After a month of analysis your pressures have changed. What is the most likely cause of the problem in each of the three scenarios below?

Scenario One:

Column Pressure Reagent 1 Pressure Reagent 2 Pressure
100 bar 430 psi 330 psi
  1. Pre-column GARD blocked
  2. Heated Reactor obstructed
  3. Ambient Reactor obstructed

Scenario Two:

Column Pressure Reagent 1 Pressure Reagent 2 Pressure
100 bar 430 psi 430 psi
  1.  Pre-column GARD blocked
  2. Heated Reactor obstructed
  3. Ambient Reactor obstructed

Scenario Three:

Column Pressure Reagent 1 Pressure Reagent 2 Pressure
180 bar 230 psi 130 psi
  1. Pre-column GARD blocked
  2. Heated Reactor obstructed
  3. Ambient Reactor obstructed
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Pickering Laboratories in 2013

1 Comment

By Wendy Rasmussen

In recent years, we have released several new products and applications, and with still more on the horizon, it occurred to me that now would be a great time to summarize the Pickering of today – our mindset and our wide variety of products & applications.

Acai Berries
Acai Berries

No longer are we simply the “Post-Column Company”. We are the “Automated-Sample Antioxidants” company.  Think of us as the new “super fruit.” The Acai berry, or perhaps the new Chia Seeds (incidentally, we do have a post-column application for the identification & quantitation of  Antioxidants in a variety of matrices).

We are still very active, and we as a company plan to be here for many years to come. We are still the company founded on chemistry and a desire to to teach, to spread our technical expertise, to support our customers.

It’s been a few years now since Pickering began distributing and supporting our LCTech Product line.  The products have shown an ever increasing interest here in the US and in Canada (our official Sales Territory for this product line). We are very proud to offer these products and we hope we can develop it further in the future.

Historically, we have provided the back-end of an analysis (post-column derivatization). Nowadays, we can provide the front-end of analysis as well (the sample-cleanup).

In thinking about our product offerings, I realized that a simple list does not effectively show the scope of the products we have to offer in 2013 – primarily because we have a lot of overlap between products and product lines.  We’re not a vertical company in that regard.  I suppose one could say our product offerings are more circular in that many do not fall into a single distinct category.  I am a very visual person, and for me, a Venn diagram and our overall “product scale” really helped to understand and clarify our products:

Venn Diagram of Pickering Laboratories
Venn Diagram of Pickering Laboratories
General "Product Scale" for Pickering Offerings
General “Product Scale” for Pickering Offerings
For those of who like lists, you can find one Here, on Pickering’s website, and on LCTech’s Website

For any Questions, please feel free to contact us:

Pickering Laboratories, Inc.
Mountain View, California
Email: sales@pickeringlabs.com
Phone: (direct) 650-694-6700 or (toll-free) 800-654-3330

 

Image of Acai Berries:  http://acaiberryeducation.com/