All posts by Pickering Laboratories

Attending NACRW and Enjoying Florida

By Sareeta Nerkar

The North American Chemical Residue Workshop (NACRW), formerly known as the Florida Pesticide Residue Workshop, was held in Naples, Florida. For the 56th consecutive year, laboratory professionals met to discuss the latest trends in the analysis of pesticides, veterinary drugs and other chemical residues. The big topics at this meeting were cannabis analysis, novel and emerging contaminants in drinking water and food matrices, and finally trends in veterinary drug residue control. Sareeta Nerkar and Maria Ofitserova both attended this year, representing Pickering Laboratories at our booth and in several key technical and vendor presentations.

Broader acceptance of cannabis for medical use has increased the need for analytical methods capable of determining the active compounds as well as methods to detect contaminants such as pesticide residues, mycotoxins and traces of organic solvents. Cannabinoids are a class of terpenophenolic compounds that are associated with the pharmacological activity of cannabis. Cannabinoids exist in the plant mainly as carboxylic acids that are not physiologically active. The compounds are converted to neutral analogs by light and heat while in storage or during the preparation of edible products. Acids are also converted to their neutral analogs during GC analysis, which often causes differences in testing results when compared with HPLC analytical methods.

Pickering Laboratories has developed a new post-column derivatization method to analyze cannabinoids in cannabis plants and cannabis-containing edible products. This post-column method is based on reaction with Fast Blue Salt reagent under basic conditions, a well-known color-forming reaction that is used in drug tests to detect cannabinoids via test-tube methods and thin-layer chromatography. After derivatization, detection at 475 nm is performed using a UV/Vis detector. The same post-column method was used for analyzing cannabinoids in hemp but with a modified sample preparation procedure that was easier and faster.

At the NACRW conference, there was considerable interest in the Pickering Laboratories methods for testing cannabinoids and mycotoxins in hemp because they are simple, robust and economical.

Sareeta Nerkar enjoyed giving her oral presentation on Improved Extraction and Cleanup Prior to HPLC Determination of Glyphosate in Food Samples!  Her talk presented a simple and robust post-column method for the analysis of Glyphosate at sub-ppm levels in many different types of foods. The method’s accelerated sample preparation improves throughput of the samples and reduces testing costs for busy laboratories.  Many laboratories are looking for accelerated sample preparation and analysis of glyphosate at low levels with no matrix interferences, and Pickering Laboratories has the answer!

Sareeta also shared her poster on Analysis of Mycotoxins in Cannabis Plant and Cannabis-containing Products, which was well received.  Please always feel free to contact us for more information or check out our webpage.

Pickering Laboratories sponsored a lunch vendor seminar during tne conference, where Maria Ofitserova introduced the Onyx PCX, the newest addition to our integrated family of post-column derivatization instruments, chemistry and support.  The seminar included all the Onyx PCX instrument features as presented by Maria, then Sareeta followed up by presenting our latest research and method development on hemp!

All of the Pickering Laboratories presentations are available on the NACRW website.  Overall, Maria and Sareeta had a great conference and really appreciated all of your interest in our latest Onyx PCX and new post-column methods and applications!

Hemp in the News, Cannabinoids in the Hemp

By Maria Ofitserova

The United States 2018 Farm Bill changed the legal status of both domestic hemp cultivation and manufacturing of products that include parts or derivatives of hemp plants, including cannabidiol (CBD) derived from hemp. Moving forward, after obtaining the approval from the USDA, the individual States will assume primary regulatory authority over the hemp industry. The States need to present their plans for regulating hemp industry and otherwise be subject to USDA regulations. Unfortunately, there are several issues causing delays with release of standardized rules, the main problem being the absence of Federal delta-9 tetrahydrocannabinol (THC) testing standards. Testing for the presence of THC is necessary to distinguish hemp from marijuana.

According to the Farm Bill, hemp should have no more than 0.3 % of THC present. In Cannabis sativa plants, THC is present in the neutral form as delta-9 tetrahydrocannabinol, as well as in carboxylated form as delta-9-tetrahydrocannabinolic acid (THCA). Heat causes decarboxylation of delta-9 tetrahydrocannabinolic acid, converting it to tetrahydrocannabinol. The Farm Bill doesn’t specify what forms of THC should not exceed 0.3 % but it does mention that testing procedure should utilize “post-decarboxylation or other similarly reliable methods.” The phrase “other similarly reliable methods” creates confusion as to the principle of the methods that could be used.

Using Gas Chromatography would be considered a “post-carboxylation method,” but this technique doesn’t allow the analyst to obtain the actual cannabinoids profile for hemp and/or marijuana, since elevated temperature causes chemical changes to the compounds in the sample… And having information about different forms of cannabinoids present in the plant is important to growers and product manufacturers alike, since this may affect the price of the crop.

The HPLC technique is much more useful for testing cannabinoids in hemp since it is able to differentiate between the forms of cannabinoids. The HPLC method allows the analyst to determine neutral and carboxylated forms of cannabinoids separately and gives flexibility in the ways of reporting composition.  Comments from the USDA do suggest that total THC concentration, meaning THC naturally present in neutral form as well as formed from delta-9 Tetrahydrocannabinolic acid, should be taken into account when classifying Cannabis sativa as hemp. Note to analysts: when doing calculations for total THC, one should keep in mind that due to differences in molecular weight a coefficient of 0.877 should be used to convert THCA percent to THC percent. 

Pickering Laboratories, Inc. has developed a simple HPLC method with post-column derivatization for the analysis of cannabinoids, including THC, THCA, CBD and CBDA. The method can be used for analysis of both hemp and marijuana. Post-column derivatization decreases matrix interferences and increases sensitivity of detection since the reagent is specific for cannabinoids. This technique eliminates the need for sample clean-up, so a simple extraction is sufficient to successfully analyze not only plant materials but also finished products containing hemp, for example edibles and supplements.

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! 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 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.)




WEAR Conference 2019

By Saji George

Appropriate product testing should be set in place by any manufacturer of consumer goods to ensure quality, reliability and high-quality products. It is important to test the functionality of the product but it is also wise to test the product in the type of system in which it will be functioning. To determine the endurance without waiting out the life of the product, stress testing should be an integral part of product testing protocols. Pickering Laboratories’ artificial body fluids play an important role in these stress tests.

The WEAR Conference brings together leading smart fabric and wearable device experts. Attendees at this conference will include business development managers, chief innovation officers, creative directors, material scientists and developers of wearable consumer products and their components. Pickering Laboratories Inc. is proud to be sponsoring WEAR 2019 in Seattle, Washington; Saji George and Rebecca Smith will both be in attendance. We are looking forward to meeting with our existing customers and making lots of new connections with industry leaders in this exciting field!

Looking Ahead to NACRW 2019!

By Sareeta Nerkar

The North American Chemical Residue Workshop (NACRW) conducts an annual meeting catered to scientists who are particularly interested in trace level analysis of pesticides, veterinary drug residues and other chemicals in food, animal feed and environmental samples. Formerly named the Florida Pesticide Residue Workshop (FPRW), this year marks the 56th Annual Conference!

Two of our research chemists will be traveling to Naples, Florida from July 21-24, and they hope to get a chance to meet customers face-to-face and compare notes on the latest research and upcoming industry needs! Sareeta Nerkar will be joined by Maria Ofitserova in representing Pickering Laboratories at the meeting. In addition to sponsoring a luncheon, Sareeta and Maria will be hosting a vendor seminar on Wednesday, July 24 that will include the latest post-column applications, including Mycotoxins Analysis in Hemp and additional exciting news.

Sareeta is also looking forward to her oral presentation Tuesday, July 23 on Improved Extraction and Cleanup Prior to HPLC Determination of Glyphosate in Food Samples. She will be discussing a simple and robust method for the analysis of Glyphosate at sub-ppm levels in different kinds of food. The accelerated sample preparation improves sample throughput and reduces the cost of analysis for busy testing laboratories using the post-column Glyphosate method!

The Pickering Laboratories poster for the conference this year is on the Analysis of Mycotoxins in Cannabis Plants and Cannabis-containing Products, so please look for Sareeta during the poster session!


Come One, Come All to NEMC 2019!

By Rebecca Smith and David Mazawa

This year the annual National Environmental Monitoring Conference (NEMC) heads south to Jacksonville, Florida, where chemists and environmental regulators from around the country will gather from August 5-9, 2019.  The August weather and the technical program will both be heating up as David and Rebecca check out the latest research in environmental monitoring and methodology. 

Please stop by our booth to chat with us about the latest post-column developments and newest product testing solutions.  Or, even better, come find us at the New Technology Showcase on Tuesday, August 6th from 3:00 – 5:00 pm!  David will be joining other instrument manufacturers to discuss the latest innovations in analytical instrumentation. 

Finally, we’re excited to be included in this year’s selection of drinking water poster presentations!  David and Rebecca will gladly discuss our poster with you when we see you at the show.  For reference, it is titled: HIGHLY SENSITIVE ANALYSIS OF CHROMIUM (VI) IN DRINKING WATER BY ION CHROMATOGRAPHY (IC) WITH POST-COLUMN DERIVATIZATION AND UV/VIS DETECTION.

Pittcon 2019: Recap from Philadelphia

By Mike Gottschalk and Maria Ofitserova

Philadelphia, Pennsylvania was the site of Pittcon 2019 and Pickering Laboratories was one of over 1,000 exhibitors at the convention center.  As Philadelphia is centered between the New York and Washington D.C., the location brought us close to many of our customers and soon-to-be customers particularly in the pharmaceutical industry. 

Maria, Rebecca and I spent three days exhibiting and providing information on the latest post-column derivatization applications, not to mention showing off all the new products in our Pickering Test Solutions product line.  Our promotional giveaways were a big hit and we greatly underestimated how popular the Pickering yoga mats and exercise balls would be!  Hopefully you stopped by our booth early if you enjoy a good workout while you travel.

We are always pleased by the amount of interested people who stop by to discuss our Product Testing Solutions. We often hear “I didn’t know you made artificial perspiration?”  They will ask us to explain the many types of consumer products that need to be tested with perspiration as well as saliva, urine and other simulated body fluids. You might have noticed that for the last three years, we’ve tried a “sweaty” theme for our show giveaways!  It’s been a great way to promote discussions about product testing and how important it is for almost every industry to evaluate materials with artificial bodily fluids.

One of the new focuses for our post-column research and development has been the growing market for Cannabis related products and the testing of Cannabis.  This field (pun intended?) has shown increasing and sustained interest in cannabinoids and contaminants testing.  There’s good interest in the post-column applications we’ve developed for these matrices, and it reflects the industry demand for verified testing applications.  Highlighted at the show were our applications for the Analysis of Mycotoxins in Cannabis and the Analysis of Cannabinoids in Cannabis and Cannabis-containing Edible Products.

While at Pittcon, we hosted a daily raffle at our booth.  Each expo day, we chose a winner for a pair of Bose “Sleepbuds” – noise cancelling earbuds specifically designed to help the wearer get awesome sleep!  Congratulations to our winners William Collin from General Motors, Brent Hanlin from ALS, and Keith Saroka from the Interboro School District.  This picture really captures how pleased these lucky winners were!

Thank you to everyone who came by the booth to visit with us in Philly this year – we had so much fun chatting with you all!  And of course, if you ever want more information between shows, we’re always adding fun new things to our website and introducing new products in our quarterly newsletter.  Please email to discuss any new applications with Maria or another of our amazing chemists!