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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 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


Glyphosate Testing Updates

1-cornBack in May, we reported on new developments in food testing and the beginning of FDA (Food and Drug Administration) participation in testing for Glyphosate residues in food.  This new FDA directive was in line with growing international concern over the safety of Glyphosate, and increased domestic pressure from consumer groups, academics and testing laboratories.  Pickering Laboratories has been excited to assist our Glyphosate-testing environmental customers with learning the new food matrices, and our food testing customers with learning a new Glyphosate application.

During the September 2016 AOAC International meeting in Dallas, Pickering Laboratories presented an improved post-column method for Glyphosate analysis in foods with simplified sample preparation procedure. This method was successfully applied to Glyphosate analysis in oats, wheat flour, eggs, milk, soybeans, corn and beer. The method is capable of analyzing Glyphosate at levels well below legal limits with high precision and accuracy. Our poster generated a lot of interest among AOAC meeting attendees. We received inquiries from laboratories doing pesticides testing as well as other attendees who, despite not being involved in Glyphosate analysis, expressed concerns at the indications of presence of Glyphosate in common foods, especially cereals. A copy of our application note can be found on our webpage.

Legal tolerances for Glyphosate vary widely from country to country. For example, the limits for oatmeal range from 0.1 ppm in Australia to 15-20 ppm in Canada, Europe and United States. In May 2016, Taiwan recalled close to 62,000 kg of Quakers Oats products due to Glyphosate contamination with up to 1.8 ppm present. Other reports also indicate that Glyphosate contamination of oat-containing and wheat-containing cereals is commonly found at levels close to and above 1 ppm. These findings are not surprising considering prevalence of Glyphosate use as a pre-harvest desiccant for many crops (including oats and wheat). Though 1-2 ppm levels of Glyphosate are well below the legal tolerances within the United States, the amount of cereals commonly consumed by people, including young children, range from 50-100 grams per day. Those quantities easily bring a person’s daily exposure to Glyphosate to almost 0.2 mg, and that is just from breakfast.

In light of mounting evidence of the pervasive presence of low levels of Glyphosate in a wide variety of common foods, we find it unfortunate that the FDA reportedly has halted the testing of Glyphosate in food products, citing the need to develop consistent methods amongst the different FDA laboratories. On the other hand, the European Food Safety Authority (EFSA) reported proposing to extend their pesticide residue monitoring program, with special attention to Glyphosate monitoring, including mandatory analysis of Glyphosate in crops such as soy beans, rapeseeds (Canola) and barley. We certainly hope the FDA would follow suit and Glyphosate food testing will soon resume. We believe Pickering Laboratories’ method would be a perfect candidate for the Glyphosate monitoring program.

Random Tangent – African Safari Edition!

By Michael Pickering

My wife and I had the great pleasure of traveling to Kenya this year for a couple of weeks.  As Judy and her friend (our traveling companion) are both avid photographers, we’ve got some spectacular pictures to share.  Everyone at Pickering Labs has enjoyed the stories and photos, and I am hoping that you’ll find them entertaining as well.

Judy and I visited five conservancies in total while we were in Kenya, traveling around for the better part of three weeks.  As such, we have thousands of animal photos to share, which I am told is a bit too many for the Pickering Labs webpage.  So, Judy has helped me select several choices for public consumption and we have included links to the places we have traveled for more information than I will detail here.

In Nairobi, we first visited the Sheldrick Wildlife Trust.  This conservancy focuses on the protection and preservation of elephants and rhinos.  We were able to visit with orphaned elephants, and even saw that the baby elephants learn to bottle-feed themselves during their fostering!  In the second picture below, you can see me posing with Mbegu, the orphaned elephant we “adopted” during our visit.  She came to the conservancy at a very young age and injured, but we are happy to report she has made a full recovery and is thriving in her new community of orphaned elephants and their faithful and hardworking keepers.

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From Nairobi we continued north to Sambaru, where we were able to see a lot of African wildlife!  We watched elephants drinking from wells that the local people maintain for both themselves and the wildlife.  We also saw Grevy zebra (an endangered species) and cheetas when we visited the Lewa Wilderness Camp.  In addition to staying in the lodge, we also visited some of the 62,000 acres of conserved lands there.

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Lewa lands are home to over 70 different animal species and 350 different bird species.  Lewa is particularly famous as a leading rhino sanctuary, so I wanted to share a photo of the Black Rhino with you.  We also learned that of the 3,000 Grevy zebra remaining worldwide, a full 20% make their home on this conservancy.  The birds we spotted onsite were spectacular!  Here is a picture of the lilac-breasted roller and a pair of crowned cranes for your enjoyment.

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Inspired by the multitudes of birds surrounding us, I was also eager to take flight!  Lewa has an amazing biplane, and although Judy remained earthbound, I was able to take a ride in the skies and view the wildlife from a whole new vantage point!  The biplane experience came complete with the classy attire necessary to remain comfortable during the ride, much to my wife’s delight.

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We travelled to a Maasai village and the local warriors performed traditional dancing to welcome me to their village.  You can see in the photo below how incredibly high they jump!  Judy has video of this dancing, and my attempts to join in on the fun, but there are some visuals best left to the imagination.  Let’s just say that when Judy tells this story at the lab, everyone is cracking up by the time she’s done.

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From there, we crossed the equator and visited Ol Pejeta Conversancy and saw lions and warthogs pictured above.  Ol Pejeta is the largest Black Rhino conservancy in East Africa, with 108 Black Rhinos on site.  We also visited their Endangered Species Enclosure and below you will see a picture of me meeting the last male Northern White Rhino on the planet. 

Cmp17soloonsidered extinct in the wild, the last three Northern White Rhinos are protected at Ol Pejeta, where they are kept under 24-hour armed guard and enjoy a 700-arce enclosure.  Unfortunately, breeding efforts have proven unsuccessful – it has been determined that the females, Fatu and Najin, are unable to naturally reproduce.  Sudan, the 43-year old male in the picture, is an older fellow and his sperm count is pretty low…  But there is hope that artificially-assisted reproduction is a possibility and the Northern White Rhino subspecies can be saved from complete extinction.  This is an international effort, and you can learn more about the efforts taking place right here in California on the San Diego Zoo’s webpage

From Ol Pejeta, we flew to the Masai Mara Reserve, which is where the prey animals cross the Mara River.  Although the Wildebeest migration occurs between July-October, we missed the massive herds moving through.  Instead, we saw a whole lot of hippos!  You can see them below, and notice the baby sunbathing with mom!  We also took photos of more cheetahs and lions.  I won’t share those particular pictures, but these lions were definitely an actively mating pair!

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After Ol Pejeta, we traveled to our final stop at the Amboseli National Park.  We found the highlight of our time there to be the herds of Maasai giraffe.  Particularly fun was watching them drinking from a pond, as you can see in these pictures.

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mp23On our very last day in Kenya, we were treated to a rare treat.  I was sitting outside the lodge, soaking in the sights and sun, when I spotted movement at the edge of the lawn.  There was some distance of grass forming a manmade lawn, and from there a clear edge to more natural foliage, fallen leaf debris and assorted bush.  Running parallel to the lawn, I watched as something moved just exactly along the edge.  Of course I needed to evaluate from a closer distance, so I called to Judy to bring the camera and set out across the grass.  A snake!  How excellent!  By the time Judy arrived with the camera it had moved off some ways into the brush, but we were able to take enough pictures that, combined with my detailed descriptions, the lodge safari guide was able to find the snake in his book: a black-necked spitting cobra!  Truly a delightful find. 


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 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








2016 Environmental Measurement Symposium

NEMC-PhotoRebecca Smith and David Mazawa hopped on a quick flight down to John Wayne Airport earlier this month, but they weren’t heading to Disneyland!  Pickering Laboratories, Inc. was proud to sponsor and exhibit at the 2016 Environmental Measurement Symposium, which is the combined meeting of the Forum on Environmental Accreditation and the National Environmental Monitoring Conference (NEMC).  This year’s meeting was held at the Hyatt Regency in Orange County, CA, a short five minute drive from the happiest place on earth.  Not that we took the time to ride the Matterhorn… We were hard at work, of course!

When not enjoying conversations with customers and attendees at our booth, we attended many enlightening talks which covered all ranges of topics from medical marijuana to metals speciation…  Additionally, the focus this year on Citizen Science was particularly engaging.  Rebecca learned that 15% of people living in the U.S. are drinking unregulated water – private wells are much more prevalent than she previously thought!  And one speaker in particular was even able to directly tie in Pokemon Go!

Rebecca and David presented a poster on Glyphosate Analysis in Soy Beans, Corn and Sunflower Seeds which had been a big hit at the North American Chemical Residue Workshop in Florida.  They found, however, that the booth raffle for a Kindle Oasis was a much bigger draw than the poster presentation!  Attendees had three days to enter their business cards for the raffle, and during lunch on Wednesday we had our fabulous booth neighbor Bridget Wallace at XOS draw the big winner…

The winner of our Kindle Oasis raffle was Houri Mandjikian from LA Department of Water and Power. Congratulations Houri!  She was able to pick up her new Kindle Oasis at the booth during our sponsored afternoon break on Wednesday.  Thank you to Houri and all of our participants in the raffle.

So, with NEMC 2016 wrapped up, you’re probably wondering what we’re up to next?!

Rebecca will be heading to St. Louis next month to participate in the ACIL Annual Meeting.  She’s looking forward to seeing some of you there… and getting a chance to watch the St. Louis Cardinals on their home field!  (Her grandfather is a huge Cardinals fan from his childhood.)

David is looking ahead to AOAC International 2016 and taking a trip to Dallas.  He and Mike Gottschalk will be there, along with our AOAC-involved chemist Maria Ofitserova who always has a busy schedule during the meeting.  Maria recently had her Theanine method accepted as an official AOAC method, so I am sure she will be excited to answer any questions about it!

We hope to see you at one of our next shows!


Chromatography Quiz #24

Chromatography Quiz #23 Results

bosePickering Labs would like to congratulate our winners of our last newsletter’s AAA quiz: Wanda Ingersoll from Mississippi Public Health Lab, David Green from Pepperdine University Natural Science Division, Narjes Ghafoori from LA County Environmental Toxicology Lab, and Helene Lachance from Shur-Gain Nutreco!  

They have each won and will shortly be receiving: a Bose SoundLink Color Bluetooth Speaker! A lightweight-compact wireless speaker in a stylish-vibrant color! Connect to any bluetooth device and take your tunes to go! We hope our quiz winners enjoy their prizes for the remainder of the summer and beyond!

Thank you all for your submissions! 



The correct answer to the Polyether Antibiotics Analysis quiz:

It was beautifully answered by one of our winners. Here is their response:

Multiple Choices:

A) Bad lamp

B) Reference Wavelength

C) Sampling rate

D) All of the above

“This appears to be a really bad choice of reference wavelength. The vanillin absorbs like crazy from 200-350 nm. At almost 60g/L the reference absorption will be topped out at >4AU. No DAD detector I know of can handle this. The noise is simply the remaining electronic noise from the 360 nm (plus bandwidth) diodes on the array. The solution is to move the ref wavelength out to, say, 600 nm since the antibiotics probably don't absorb there or, better, turn off the ref wavelength, acquire and store whole spectra, and do post-processing after the analysis when a clear region of the spectrum can be found.”

Chromatography Quiz #24: Glyphosate Peak Shape

What caused the bad Glyphosate peak shape in the troubleshooting (red) chromatogram below?  Simply email your answer as well as your full contact information to Rebecca at by October 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). 

Glyphosate Analysis – Bad Peak Shape

Pinnacle PCX post-column instrument is being used, in a traditional HPLC setup as recommended by Pickering Laboratories.  The reference (blue) signal and troubleshooting (red) signal are overlaid in the chromatogram below.  The quiz question: what is causing the bad peak shape?  

Hint: Please assume the same reagent, column, and method are being used for both chromatograms.

Normal/reference post-column conditions for glyphosate analysis:
Reagent 1: GA116 – hydrolysis reagent
Reagent 2: GA104 with OPA and Thiofluor
Reactor: 36 °C, 0.5 mL
Reagent flow rate: 0.3 mL/min
Injection volume: 100uL







FDA Announces New Glyphosate Testing in Food

Maria Ofitserova Ph D. – Pickering Laboratories

Glyphosate, the active ingredient in Roundup, is the most widely used herbicide in the world. In the US, the Environmental Protection Agency (EPA) regulates Glyphosate and sets residue limits for different crops as well as drinking water.  Recent research, however, has raised concerns about Glyphosate safety and its prevalence in the environment.  The International Agency for Research on Cancer (IARC) rated Glyphosate as “probably carcinogenic to humans” and several studies, including one conducted by Germany’s Federal Environment Agency (UBA), have indicated a massive increase in the number of human urine samples contaminated with Glyphosate over the last 15 years.

The increased use of Glyphosate has been studied as well. According to Bill Freese, a science policy analyst with the Center for Food Safety, 50 times more Glyphosate is allowed on corn grain now than was allowed in 1996.  The US-EPA has also increased what it considers to be a safe amount of Glyphosate exposure by a factor of 17.  The EPA's high-end estimate of infant exposure to Glyphosate exceeds the level considered safe for them in 1983, Freese adds.

GlyphosateAs the scrutiny of Glyphosate grows in the United States, a U.S. Government Accountability Office report has criticized the Food and Drug Administration (FDA) for not sufficiently monitoring residues of the chemical on foods. This February, the FDA announced testing of Glyphosate in foods including soybeans, corn, milk, and eggs. Meanwhile, consumer groups, academics and testing laboratories have claimed to have detected Glyphosate in breast milk, honey, cereal, wheat flour, soy sauce, and infant formula as well.

The herbicide registration renewal of Glyphosate in the European Union was questioned due to mounting evidence of chronic human exposure and insufficient safety data, especially in children, and a suspected link to cancer.  As of now, the decision on relicensing has been postponed.  Several EU members, such as France, Sweden, Netherlands and Italy, have indicated opposition to renewal of the 15-year license.

With this growing international concern about Glyphosate, additional regulations from the US-FDA and international regulatory agencies are possible in the upcoming months and years.

Pickering Laboratories has over 30 years’ experience manufacturing and selling instruments and reagents for Glyphosate analysis in accordance to the US-EPA Method 547 for Glyphosate Analysis in Drinking Water as well as the AOAC Method 991.08 for Glyphosate Analysis in Environmental Waters. These HPLC methods are based on post-column derivatization technology with florescence detection.  The AOAC Official Method 2002.52 for Analysis of Glyphosate in Crops describes easy clean-up procedures that are successfully combined with Pickering Laboratories’ post-column derivatization for analysis of Glyphosate in crops such as soy, corn, alfalfa, and sunflower seeds as well as vegetables such as tomatoes and broccoli. The analytical method is sensitive and selective, and it can be easily implemented in any laboratory. For further details visit our webpage at:   

Please enjoy these excellent additional resources/sources: