All posts by Pickering Laboratories

Quiz – Winter 2024

Quiz #44 – Amino Acids Noisy Baseline

In this amino acids chromatogram per European Pharmacopeia (method abstract here), you will see a noisy baseline with repetitive sinusoidal noise pattern (green and blue). What is contributing to this baseline noise?

Submit your answers to by March 15, 2024.


Announcing the winners of our previous quiz, Chromatography Quiz #43 – Polyether Antibiotics

Pickering Laboratories would like to congratulate the winners for our previous newsletter’s Chromatography Quiz #42: Josiah Hakala from Minnesota Department of Health, Narjes Ghafoori from Los Angeles County Public Health Laboratory, and Thomas Schneider from SCWA. 

In celebration of our polyether antibiotics method and decades-long relationship supporting the animal feed industry, our quiz winners will each soon be receiving: a beautiful custom cutting board, designed and made by family-owned Trujillo Ranch and sold via Etsy! 

This personalized cherry wood cutting board with a highland cow is 11 x 17 and approximately an inch thick.

Congratulations to our quiz winners!  Thank you all for your submissions!


Chromatography Quiz #43 Solution:

Polyether Antibiotics are commonly used for preventing coccidiosis and other infections in poultry and for improving feed efficiency for beef cattle and swine. The use of Polyether Antibiotics is strictly regulated, with only specific ionophores approved for use in feeds intended for different animals.

Analysis of Polyether Antibiotics by HPLC with post-column derivatization and UV/Vis detection has been proven to successfully identify and quantify Monensin, Narasin and Salinomycin in medicated feeds, supplements and premixes as well as to determine trace contamination levels in non-medicated feeds.

Post-column derivatization of Polyether Antibiotics is done using highly acidic Vanillin or DMAB reagents. The Onyx PCX derivatization system (Pickering Laboratories, Inc.) has an inert flow path and automated system wash capabilities that make it uniquely suitable for handling corrosive reagents. The two-pump system is recommended to extend reagent stability, but the single-pump system for this application is also available.

Adding a Fluorescence detector to the instrumentation allows for using the same extraction procedure and HPLC conditions to also determine Lasalocid, which doesn’t require post-column derivatization.

The method details can be found on our website here.


Question: What could be contributing to the loss of signal?

Correct answer:

In this case, the loss of signal was due to incorrect plumbing of the post-column system. Our Polyether Antibiotics systems are plumbed so that Reagents 1 and 2 will premix before reacting with the analytes of interest in the heated reaction coil. Both reagents and heat are required to have a sufficient post-column reaction. You can mix reagents 1 and 2 ahead of time and only use one reagent pump to deliver, however, the reagent is unstable. We can extend the stability of the reagent by mixing them “on the fly” in this manner.

Our incorrect plumbing had Reagent 1 mixing with the analytes of interest in the heated reaction coil before it had a chance to mix with Reagent 2, which contains our Vanillin reagent.


The typical flow diagram for the Polyether Antibiotics post-column system is shown here:

Good Chromatogram:

Bad Chromatogram:

Young In/Chromass Youtube Videos

Excellent Videos from International Partner: Young In Chromass

By: David Mazawa

Are you in the mood for a quick, visual primer on your favorite post-column instruments and applications from Pickering Laboratories?  Look no further than the links below!

Our dealer in Korea, Young In Chromass, made very helpful and informative YouTube videos that give a great representation on the Post-Column technique and instrumentation, as well as more specifically on the methods for Amino Acid Analysis.  The first video highlights our top-selling Onyx PCX as well as several of our most popular applications.

In the Amino Acids video, you will see a comparison between the Ninhydrin and OPA methods, while also learning the advantages of the Post-Column technique over other methods of Amino Acids Analysis. Perhaps you will come to the same conclusion we have: Post-Column is the easiest, most reproducible technique available!

Young In Chromass has been a trusted international distributor for Pickering Laboratories’ instrumentation and consumables for over 20 years.  We are very thankful for this partnership!  You can visit their website here:


Pittcon – San Diego

Almost Here: Pittcon 2024!

By: Kevin McKeown

Pittcon 2024 kicks off another year of our conference circuit, and brings with it another opportunity to meet with our customers, partners and international dealers in person!

This year, Pittcon will be held in the beautiful and typically very pleasant San Diego!  It’s the first time in my 15+ years of attending the conference that it has been west of New Orleans, which is a really nice change of pace and will hopefully let some brand-new attendees have the opportunity to see all the latest and greatest from our industry.

Pickering Laboratories will be at Booth # 2321 and we encourage everyone to stop by!  Our all-star booth lineup will include: Rebecca Smith, Maria Ofitserova and Kevin McKeown.  We will have one of our flagship instruments, the Onyx PCX, available to check out.  In addition, we’re debuting beautiful printed copies of the new Product Testing Solutions brochure, which was also written up in this newsletter.

We are taking advantage of hourly flights between the Bay Area and San Diego to additionally invite our Purchasing Agent and Production Manager down for a day to walk the expo and meet with some of our suppliers and vendor partners!  Both Kristina Wilkinson and Christopher Nguyen will be in San Diego on Tuesday 2/27, so reach out via email or call us if you’d like to arrange a meeting!  Another good chance to put a face to the name of some longtime collaborators.

Stop by and pick up some of our fun Pickering Labs branded giveaways, including sunscreen(!) that will undoubtedly drive away the atmospheric river that has parked itself over Southern California this week.

Safe travels and see you in San Diego!

New Employee Spotlight – Kim

New Employee Spotlight – Kimberly Genet

By: Kevin McKeown

I bet you thought that we were done with new employees, but you were mistaken!  Pickering Laboratories is happy to introduce ANOTHER new member to our team: Kimberly Genet!

Kim joined us in early September 2023, stepping into her role as a Customer Service Representative.  I have no doubt that some of you reading this newsletter may have already had a chance to communicate and work with Kim in the past months.  As an experienced CSR, she was able to get up to speed quickly and start impacting our customers’ experiences almost immediately! 

Outside of work, Kim enjoys listening to audiobooks, particularly memoirs and books on personal development.  Kim has three children and loves going to live concerts with them.  She also practices yoga and paints in her spare time.

Kim is originally from O’ahu in Hawaii and is very proud her heritage.  Maybe next time our Technical Manager, David Mazawa, is on the island for one of his yearly service calls, he can get some local food recommendations?!

Kim always has a smile on her face (which is noticeable even through the phone or keyboard!) and we are very lucky to have her joining us. 

Happy to have you on the team, Kim!!

New Employee Spotlight – Jose

New Employee Spotlight – Jose Guardado

By: Christopher Nguyen


Our employee family is still growing: Pickering Laboratories is happy to introduce the newest member of our team: Jose Guardado!

Jose joined us in December 2023, jumping into his new role as a Production Chemist right before our holiday week.  As a new member in our Production department, Jose has a lot of experienced teammates to learn from – and he’s taken full advantage!  With the volume increases in our buffers, reagents and artificial body fluid product lines, this has been a very busy time and Jose is killing it!

When he’s not in the laboratory, Jose enjoys music.  He spends time playing his bass guitar and attending Rock, Punk and Metal shows around the Bay Area.  He also stays active; Jose can frequently be found jogging and playing his favorite sports, soccer and hockey.  I’d be doing a great disservice to our Winter Newsletter if I didn’t also mention that Jose likes to travel, especially checking out new places to go snowboarding.

Jose comes to Pickering with a strong background for our exact type of manufacturing; among other skills, he’s packed analytical columns in his recent work past.  Additionally, he has experience with sublimination and has work closely with the bottling/capping machines that we so dearly depend on!

It is always great to expand our workforce and we couldn’t be happier to have Jose as a new employee at Pickering Labs.

Welcome, Jose!!

Reverse Phase Guard Update

Product Obsoletion Notice:

18ECG001 Guard Cartridge Holder with 3 guard cartridges (Obsolete)
18ECG002 Guard Cartridges, pack of 3 (Obsolete)
Effective: 16 Oct 2023

Dear valued customer,

Please take note that part numbers 18ECG001 and 18ECG002 are no longer available. We are, however, able to offer a different Reverse Phase Guard solution. Unfortunately, the new Reverse Phase Guard Cartridges are not the same size as the 18ECG002 and are not backwards compatible. A new set of holder and cartridge are required when moving to the new 4.3mm format. Both are comparable in performance and can be used for the same methodologies. Cartridges should be replaced every 3 months or 300 injections.

The new part numbers are listed below:

3106-0578 Reverse Phase Guard Holder with 3 cartridges 4.3mm
3106-0579 Reverse Phase Guard Cartridge, 4.3mm, pack of 2

The following Application kits will now include 3106-0578 instead of 18ECG001:

0352-0002 Carbamate Pesticides Analysis Kit, 23+ Compounds
0352-0003 Carbamate Pesticides Analysis Kit, for EPA Method 531.1
0352-0004 Carbamate Pesticides Analysis Kit, for AOAC Method 985.23
0352-0009 Carbamate Pesticides Analysis Kit, for EPA Method 531.2
0352-0053 Multi-Residue Mycotoxin Kit
0352-0050 Aflatoxin Analysis Kit
0352-0051 Polyether Antibiotics Kit

Please contact Pickering Laboratories Support at +1 (650) 694-6700, or if you have any questions.

Amino Acid Analysis

Post-Column Amino Acid Analysis: Onyx PCX Paired with any HPLC System

The Onyx PCX post-column derivatization instrument is designed for highly customizable Amino Acid Analysis, using our expertise in post-column technology to bring high performance when used alongside any manufacturer’s HPLC.   Pickering Laboratories provides a complete application solution, guaranteeing the chromatogram of any customer using our instrumentation and consumables, regardless of sample matrix.  We at Pickering Laboratories recommend the Onyx post-column system with one of our available Amino Acid Application Kits for any new user starting a new analysis in their laboratory. 

As a quick review, Pickering Laboratories, Inc. provides a complete solution to Amino Acid Analysis. We supply columns, eluants, reagents and post-column derivatization instruments that work seamlessly with virtually any modern HPLC, so we can guarantee the accuracy and reproducibility of the analysis. Our chemists will help you choose the method and instrumentation best suited to your requirements, answer your questions regarding sample matrices or target Amino Acids, and work with you on any custom method optimization and offer continuous support in day-to-day operation.

Post-Column Reagents for Amino Acids Analysis

Pickering Laboratories offers two post-column reagents for Amino Acid Analysis: our patented Ninhydrin reagent, called Trione®, and o-Phthalaldehyde (OPA) reagent. The choice of reagent is based on compounds of interest, sensitivity requirements and available instrumentation (Table 1). Both reagents can be used with any amino acid cation-exchange column and set of eluants.

Columns and Eluants (Mobile Phase Buffers)

We manufacture a wide range of cation-exchange columns and eluants to suit your analytical needs. Sodium cation-exchange chromatography is used for the fast analysis of amino acids commonly found in hydrolyzed protein samples or simple formulations. Lithium cation-exchange is a slower technique with higher resolution, used to separate up to 50 amino acids found in complex matrixes such as biological fluids, plant extracts, foods or beverages.

Tables 2 and 3 summarize Pickering Laboratories’ columns and eluants systems. Long columns (3.0 x 250 mm), despite having the longest run times, can be useful due to their unique selectivity, which allows separating of drug metabolites and other compounds not commonly found in native sam­ples. If you don’t find the compound of interest on the chromatograms shown on our website, please contact Pickering Laboratories for advice on which column is best suited for your analysis.

Pickering Laboratories, Inc. 1280 Space Park Way / Mountain View, CA 94043 / / / 800-654-3330 / 650-694-6700