Category Archives: Ninhydrin

Amino Acid Analysis, Chromatography Quiz, Michael Pickering, Ninhydrin, Trione, Uncategorized

Chromatography Quiz #16

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Chromatography Quiz #15 Results

We would like to congratulate our grand prize winners of our last newsletter’s Amino Acids Analysis Chromatography Quiz: Tom Schneider from Suffolk County Water Authority, Jim Balk from DHHS Public Health Environmental Laboratory, and Narjes Ghafoori from LA County Environmental Toxicology Laboratory!

They have each won and will shortly be receiving: a $100 gift card for Best Buy, which can be used online or in the store!!!

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

The correct answer for the Amino Acids troubleshooting chromatogram: the baseline noise was caused by a dirty flow cell. As we have seen through several Chromatography Quizzes, baseline noise can have a variety of causes, both mechanical and chemical. In this chromatogram, the noise we are seeing is not regular or repeatable, steering us away from the HPLC pump, a trapped bubble, or the back-pressure regulator.

To learn more about baseline noise, please review Maria’s article entitled “The Art of Noise” (http://pickeringlabs-retentiontimes.com/?p=58) from a previous newsletter.

Thank you!

Pickering Labs

Chromatography Quiz #16:

We are doing something a little bit different with this quiz! Identify what’s wrong with the picture below and win a prize! Simply email your answer as well as your full contact information to Rebecca at rlsmith@pickeringlabs.com by July 1st, 2014 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 your submission).

A blast from the past: What is wrong with this picture?!

As you can probably tell from the photo, we’ve dug into Michael’s past for our quiz this quarter! Look carefully and see if you can figure out what’s wrong with this picture! If you have any questions, please feel free to email Rebecca at rlsmith@pickeringlabs.com for further guidance.

Michael_Trione Ad

Amino Acid Analysis, AOAC, china, Ninhydrin, pickering laboratories, pinnacle pcx, post-column derivatization, Trione, Whey proteing

Calculation of Whey Protein Fraction in Milk-Based Infant Formula

A method for the calculation of whey protein fraction in milk-based formula products was developed and validated by a group of researchers from Abbott Nutrition, Covance Laboratories and AOAC International. The method is based on calculating the ratio of (Asx + Ala)/(Pro+Phe) determined from the amino acid profile of the hydrolyzed sample.

The method was approved as AOAC Official First Action Method 2012.07 and is appropriate for accessing compliance with whey content requirements of GB 10765-2010 (National Food Safety Standard Infant Formula)*. It is applicable to finished products containing both intact and partially hydrolyzed whey proteins.

According to this method, the Amino Acid Profile of hydrolyzed samples is determined using cation-exchange chromatography with post-column derivatization and UV/Vis detection. The researchers used Pickering Laboratories post-column derivatization system, our patented Trione Ninhydrin reagent and Pickering Sodium analytical column and buffers.

The method performance was evaluated using non-fat dry milk and products with whey levels from 32% to 63%, including NIST Infant Formula Standard Reference Material. The repeatability ranged between 0.3 and 2.5 %, while intermediate precision were between 2.6 and 3.4%. Average recoveries ranged from 97 to 100%.

The unmatched accuracy and precision of amino acid analysis by HPLC with post-column derivatization allowed the researches to develop a robust mathematical model for calculating whey protein fraction that can be successfully applied to a wide range of products. This proved once again that post-column derivatization analysis of amino acids is still a method of choice for laboratories that require highly accurate results.

Pickering Laboratories offers a total solution for amino acids analysis, including post-column derivatization systems, reagents, columns, buffers and standards.

The reference to the published study is below. The First Action Official Method 2012.07 can also be found online at http://www.eoma.aoac.org/.

Calculation of Whey Protein Fraction in Milk-Based Infant Formula: First Action 2012.07

Authors: Wesley Jacobs, Paul Johns, Phillip Haselberger, Joseph J. Thompson, Darryl Sullivan, Steve Baugh.

Source: Journal of AOAC International, Volume 96, No. 3, 2013, pp. 502-507

 

(*) this is a Chinese Standard

AcceCLEAN, aflatoxin, amino acid, Amino Acid Analysis, amino acids, antioxidants, AOAC, AOAC's Laboratory of the Year Award, artificial perspiration, carbamate, Chromatography, clean-up, column, deoxynivalenol, detector, dietary supplements, DON, Dr. Pickering, elisa, eluvac, ergot alkaloid, freestyle, GARD, glyphosate, GPC, Guard, HPLC, immunoaffinity cleanup, Multi-residue Mycotoxin Analysis, mycotoxin, natural toxins, New Products, Ninhydrin, ochratoxin, paralytic shellfish toxin, Physiological Fluids, pickering laboratories, pinnacle, pinnacle pcx, Post-column, post-column derivatization, psp, sweat, syringe pump, Trione, UVE, vector

Pickering Laboratories in 2013

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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/

aflatoxin, Amino Acid Analysis, carbamate, chromatographic specialties, Chromatography, clean-up, eluvac, freestyle, glyphosate, GPC, herbal products, HPLC, immunoaffinity cleanup, lctech, Multi-residue Mycotoxin Analysis, mycotoxin, natural products, natural toxins, New Products, Ninhydrin, ochratoxin, pickering laboratories, pinnacle pcx, Pittcon, post-column derivatization, spe

Pickering Exhibits at Pittcon 2013

This year’s Pittcon was held in Philadelphia, Pennsylvania from March 17-21, 2013.

view of philly from the museum On display were Pinnacle PCX, EluVAC, and a video of the FREESTYLE Automated Sample Preparation Instrument.  The video was a new technique for us, and it was well received.

The video in our booth was a combination of the separate videos for each module of the FREESTYLE Automated Sample Preparation Instrument. You can view the originals here (they are very informative, and we highly recommend them): FREESTYLE VIDEOS

Wendy, Mike and David enjoyed visiting with existing and future customers, as well as our distributors from around the world, including our Canadian distributor, Chromatographic Specialties.

Before the show opened, we had the opportunity to explore the city.  Philadelphia is one of our oldest cities and is full of history and landmarks. Some of this editor’s favorites include Independence Hall and the surrounding neighborhoods, and the Art Museum (see more below).  On this trip, we explored Reading Terminal Market, and sampled that famous cuisine, the Philly Cheese steak Sandwich. I’m told it is not truly a Philly Steak sandwich unless you have it with Cheez Whiz. Any type of real cheese doesn’t count. I made that mistake on my first trip to Philadelphia, and the man behind the counter let me know it!  I wasn’t about to make that mistake again:

philly cheesesteak

The Philadelphia Museum of Art is known for its amazing collection of artwork (viewed on a previous visit), but is also made famous by the scene of Sylvester Stallone running up the stairs in the movie Rocky.  Since the author of this entry happened to be training for a race, she decided that a little cold wasn’t going to stop her. So she put on her iPod (Rocky Theme playing, of course), and ran from the hotel to the top of the steps and back (total distance: about 2.8miles).

view from the bottom

wendy philly top of steps

wendy rockyOn the return to the hotel, I came across a version of the LOVE sculpture, by American Artist Robert Indiana. I always thought it was was much bigger…

love sculpture

 

For those of you interested in learning more about the sculpture, click HERE

If you’re ever in Philadelphia, the Philadelphia Museum of Art is definitely worth a visit.

But if you can’t make the trip to Philadelphia, you could also stay home and watch Rocky…

Amino Acid Analysis, AOAC, Ninhydrin

Midwest AOAC Meeting

This year’s Midwest AOAC meeting was held in St. Louis, Missouri from June 4-6. 
It was well-attended with a good technical program.

Gateway Arch in St. Louis, MO*

At this year’s meeting we hosted an Amino Acid workshop, in which attendees learned tips and troubleshooting techniques for amino acid analysis. All analytical methods were covered, including some discussions on sample preparation for amino acids.

The post-column analysis of amino acids is a tried and true technique. By derivatizing the amino acids post-column, any matrix components which might otherwise interfere with the derivatization steps are eliminated, leaving only the amino acids to react with the reagents. This leads to exceptional reproducibility, sensitivity and ruggedness.

Our Pinnacle PCX instrument is especially suited to amino acid analysis with its heated column oven (to perform temperature gradients), and pulse-free syringe pumps. More information can be found on our website: www.pickeringlabs.com, or by downloading one of the following:
MA380:  30-Minute Amino Acid Analysis of Hydrolyzed Samples
or our Amino Acid Brochure
View of St. Louis from the top of the Arch

* Interesting Fact: Gateway Arch is part of the Jefferson National Expansion Memorial. It was designed in 1947, but construction did not begin until 1965.  It opened to the public in 1967. http://en.wikipedia.org/wiki/Gateway_Arch

AcceCLEAN, aflatoxin, Amino Acid Analysis, amino acids, antioxidants, artificial perspiration, carbamate, clean-up, deoxynivalenol, dietary supplements, elisa, eluvac, ergot alkaloid, freestyle, glyphosate, GPC, immunoaffinity cleanup, Multi-residue Mycotoxin Analysis, mycotoxin, natural toxins, Ninhydrin, ochratoxin, paralytic shellfish toxin, pinnacle pcx, post-column derivatization, psp, syringe pump, Trione, UVE, vomitoxin

Pickering Products

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Mycotoxins: Clean-up Columns, ELISA Kits, Post-Column Derivatization Instruments & Methods, SPE manifolds (manual & automated) for the analysis of:

Aflatoxins
Ochratoxin A
DON
Nivalenol
Fumonisin FB1, FB2
Zearalenone
Ergot Alkaloids

Post-Column Derivatization: Pinnacle PCX, Vector PCX, UVE Photochemical Reactor, Columns, Reagents, Eluants for the analysis of:

Antioxidants
Mycotoxins (individual and multi-residue)
Amino Acids
Biogenic Amines
Paralytic Shellfish Toxin
Polyether Antibiotics
Hexavalent Chromium
Vitamins
Sugars
Nitrate/Nitrite
Bromate
Carbamate Pesticides
Glyphosate Herbicide
NDELA
Formaldehyde

Sample Preparation (clean-up) Instruments:

FREESTYLE for SPE, GPC, online-concentration
FREESTYLE ThermELUTE for Aflatoxin analysis (direct inject onto HPLC)
AcceCLEAN for SPE (incl. Immunoaffinity columns)
EluVAC vacuum manifold for SPE (incl. Immunoaffinity columns)
GPC QUATTRO for manual GPC Cleanup
DECS System for the cleanup of samples for Dioxin analysis

Chemistry Products:

Artificial Perspiration
Artificial Saliva
High Purity Water

Stand-Alone OEM Syringe Pump:

For any applications requiring an inert flow path, volumes up to 70mL, and pressures up to 500psi

For More Information visit:

www.pickeringlabs.com

or email: sales@pickeringlabs.com

amino acids, baseline noise, detector, glyphosate, Ninhydrin, outgassing, post-column derivatization, sine wave

The Art of Noise, by Maria Ofitserova, Senior Research Chemist

Baseline noise is a common and often frustrating problem in HPLC analysis. It makes integration difficult and adversely affects reproducibility and sensitivity of analysis. The most common sources of baseline noise are from pumps and bubbles in the lines or detectors. Not all noisy baselines can be easily explained but understanding common noise patterns will help you to determine what part of your system has a problem.

The Sine Wave
To observe the noise pattern you need to find a portion of the chromatogram that does not have any peaks and zoom in to look at about 5-10 min of the baseline. Baseline noise caused by reciprocating HPLC or post-column pump looks like a fairly regular sine wave. This kind of noise is usually due to old/poorly installed seals or bad piston. Ups and downs in the baseline follow flow/pressure variations as the piston moves. The period of the sine wave is different for different pumps. Measure the interval (in seconds) between the maximums of two waves to determine which pump is causing the noise. Most HPLC pumps have an interval of 6 -13 seconds. Pickering PCX5200 and Vector PCX reagent pumps have 2 sec and 4 sec intervals respectively. Pinnacle PCX contains a syringe pump which moves the piston in a single stroke hence it does not produce sine wave noise.

Most HPLC software programs record the column pressure during the analysis. It is very helpful to look at the trace to check if pressure variations have a similar pattern to your baseline noise. Pinnacle PCX users can also take advantage of log files collected by the Pickering software. Reagent pump pressure recorded in the log file helps Pickering technical support to evaluate the performance of the post-column system and determine if the syringe pump needs maintenance.

Bubbles
Baseline noise caused by bubbles consists of random spikes of varying amplitudes. Bubbles can occur in solvent lines or in the detector flow cell and are often caused by solutions outgassing. To prevent this from happening use a properly working degasser and install a backpressure regulator on the detector waste line to prevent boiling and outgassing in the heated reactor.

Detector Noise
Detector noise is always present and can be visible even on a “good” baseline if you zoom in deep enough. It is random and looks about the same throughout the chromatogram. An old detector lamp, dirt in a flow cell or problems with electronics can greatly increase noise level. If detector noise is suspected make sure the flow cell is clean and check the lamp hours. Built-in detector tests are also useful in assessing detector performance.

Shooting in the Dark
A common mistake people make when troubleshooting baseline noise in post-column applications is turning off the post-column reagent pump. Noise in the baseline is essentially variations in signal so it is proportional to background signal. Common eluants don’t fluoresce or absorb light in the visible range so when eluants alone go through the detector there is no signal and hence no noise. Post-column reagents, on the other hand, are often either colored or have background fluorescence so elevated noise caused by any part of HPLC system becomes visible. Turning off the reagent pump is akin to turning off the detector lamp and taking a shot in the dark – the noise is still there but we just can’t see it.

Let Us Help
When contacting Pickering support about elevated baseline noise please be ready to fax or e-mail your chromatogram and zoomed in portion of the baseline. For Pinnacle PCX users sending the log files will also help us to find the problem. You can email support@pickeringlabs.com or send a fax to 650-968-0749.