Category Archives: Amino Acid Analysis

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

1 Comment

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 Acid Analysis, Chromatography Quiz

Chromatography Quiz No. 7

Chromatography Quiz #6 Results
We would like to congratulate the grand prize winners of our last newsletter’s Aflatoxins Analysis Chromatography Quiz: Matthew Hartz and Keena Njoroge from Underwriters Laboratories, Steven Moser from the Oklahoma Dept of Agriculture, Food & Forestry, and Holger Franz from Dionex Germany! 
They have won, and will shortly be receiving: a gift basket stuffed with Starbucks coffee, tea, and treats!  Additionally, for this quiz all of our participants will each be receiving a $20 gift card from Starbucks! Again, we would like to thank you all for your submissions.  
The correct answer for the modified Aflatoxins chromatogram: The Aflatoxins G1 and B1 must be derivatized in order to achieve maximum sensitivity.  The derivatization is achieved either by reaction with Iodine, or with a photochemical reactor.  In this case, we achieved the modified chromatogram by turning off the UVE prior to injection.  The same chromatogram would be noticed if the Iodine reagent was not pumping.  
Thank you! 
Pickering Labs
Chromatography Quiz #7:
Identify the error made when running the Amino Acids chromatogram below and win a prize!  Simply email your answer as well as your full contact information to Rebecca at rlsmith@pickeringlabs.com by August 31st in order to win.  You will receive email confirmation that your submission has been received.  The troubleshooting answer and winner congratulations will be published in the next issue (to be anonymous, please notify Rebecca in submission).  
Amino Acid Analysis of Protein Hydrolysate  
Pickering Standard: 012506H, 10 μL injected of 0.25 μmole/mL standard in both chromatograms
Pickering Analytical Column: 1154150 High-Efficiency Sodium Cation-Exchange Column (4.0 x 150 mm)
Pickering GARDTM Column Protection System: 1700-3102
Normal Operating Conditions: (for reference only, condition changes may be reflected in chromatogram)
Column Temperature: 48 °C
Flow rate: 0.40 mL/min
Eluent Gradient:
TIME
1700-0112 %
Na740 %
RG011 %
0
100
0
0
12
100
0
0
34
0
100
0
53
0
100
0
53.1
0
0
100
55
0
0
100
55.1
100
0
0
67
100
0
0
Post-column conditions for amino acid analysis:
Reagent 1: Trione
Reactor 1: 130 °C, 0.5 mL
Reagent flow rate: 0.3 mL/min
Detection: UV-Vis Detector, 570 nm for primary amino acids, 440 nm for secondary amino acids
Amino Acids Chromatogram to Troubleshoot:
Amino Acids Reference Chromatogram:


Amino Acid Analysis, Chromatography Quiz

Chromatography Quiz No. 4

Chromatography Quiz #3 Results
Congratulations to the grand prize winners of our last newsletter’s Glyphosate Chromatography Quiz: Jim Balk from Nebraska DHHS Public Health Environmental Laboratory, Matthew Hartz and Keena Njoroge from Underwriters Laboratories, and Narjes Ghafoori from the County of Los Angeles Environmental Toxicology Laboratory! They have won, and will shortly be receiving from Apple.com, a new iPod Shuffle! Additionally, for this third quiz all of our participants will be receiving a $10 gift card from iTunes. Thank you all for your submissions!

The correct answer for the modified Glyphosate chromatogram: the Glyphosate ‘doublet’ is caused by injecting a sample at basic pH. An improperly buffered sample extract at a large injection volume will not mix with the mobile phase sufficiently to create the acidic pH necessary for Glyphosate to be at the proper single charge state, impacting the interaction between Glyphosate and the active sites on the column resin. Adding a couple drops of Restore TM(pH 1.3) to the sample before injection will eliminate the ‘doublet’ and return proper peak shape.
Thank you!
Pickering Labs

Chromatography Quiz #4:
Identify the error made when running the Amino Acids chromatogram below and win a prize! Simply email your answer as well as your full contact information to email Rebecca Smith by September 30th 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).

Amino Acid Analysis of Physiological Fluids
Pickering Standard: 011006P Native Sample Standard 0.25 µmole/mL, 10 µL injection
Pickering Column: 0354100T High Efficiency Lithium Cation-exchange Column, 4.0 x 100 mm
Pickering Guard Column: 0352020, 2.0 X 20 mm

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

Column Temperature: 37 °C
Flow rate: 0.35 mL/min

Eluent Gradient:

 

TIME….Li275%…….Li750%…….RG003%
0…………100……………0………………0
12……….100……………0………………0
 48………..65…………….35…………….0
90………..0………………100…………..0
95………..0………………100…………..0
120………0……………….94……………6
122………0……………….94……………6
122.1…..100……………0………………0
140……..100……………0………………0

 


Post-column conditions for amino acid analysis:
Reagent 1: Trione

 

Reactor 1: 130 °C, 0.5 mL
Reagent flow rate: 0.3 mL/min
Detection: UV-Vis Detector: 570 nm for primary amino acids, 440 nm for secondary amino acids

Post-column conditions for amino acid analysis
You can find an example of a good chromatogram page on our website.  

amino acid, Amino Acid Analysis, column, GARD, Guard, HPLC, pickering

New! GARD: Column Protection System

A new Column protection system for Cation-exchange HPLC applications will be unveiled exclusively at Pittcon this year.

The new GARD™ manufactured by Pickering Laboratories is a substantial improvement over the standard packed guards. The new GARD™ adds little pressure, is invisible to the chromatography, and has substantially more capacity for strongly retained compounds that can foul the analytical column.

The new GARD Column Protection System significantly prolongs column life without band spreading or added pressure. We will have a poster at Pittcon demonstrating, by means of a performance comparison for Amino Acid Analysis, that the use of a GARD will protect the analytical column more effectively than traditional guard cartridges, is more cost-effective for the laboratory, is easy to change, and most importantly has zero band spreading.

Amino Acid Analysis, Chromatography, Chromatography Quiz, Physiological Fluids, Post-column

Chromatography Quiz No. 2

Congratulations to the winners of our last newsletter’s Chromatography Quiz: Matthew Hartz, Jamie Palmer, and Keena Njoroge from Underwriters Laboratories, Sudheer Reddy from Chemtex, and Becky Canela from Environmental Laboratory Services!

two dozen irresistible cookiesThey’ve each won, and will shortly be receiving from Gifttree.com, two dozen irresistible cookies in five flavors: White Chocolate Hazelnut, Snickerdoodle, Peanut Butter, Oatmeal Raisin, and Chocolate Chip.

The correct answer for the modified Carbamates chromatogram: we reversed the two reagents. The OPA reagent was pumped in the Reagent One position, and the Hydrolysis reagent was pumped in the Reagent Two position. Thus 1-Naphthol, which is naturally fluorescent, appears full-sized. The other Carbamate peaks have different sizes due to their varying rate of hydrolysis – the high pH of the OPA reagent will allow for some but not complete hydrolysis prior to detection.

Chromatography Quiz: Amino Acid Analysis

Identify the error made when running the Amino Acids chromatogram below and win a prize! Simply email your answer and your full contact information to Rebecca at rlsmith@pickeringlabs.com by March 1st in order to win. The troubleshooting answer and winner congratulations will be published in the next issue (to be anonymous, please notify Rebecca in submission).

Amino Acid Analysis of Physiological Fluids:

Pickering Standard: 011006P Native Sample Standard 0.25 µmole/mL, 10 µL injection

Pickering Column: 0354100T High Efficiency Lithium Cation-exchange Column, 4.0 x 100 mm

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

Column Temperature: 36 °C

Flow rate: 0.35 mL/min

Eluent Gradient:
Amino Acid Analysis of Physiological Fluids

Post-column conditions for amino acid analysis:
Reagent 1: Trione
Reactor 1: 130 °C, 0.5 mL
Reagent flow rate: 0.3 mL/min

Detection: UV-Vis Detector, 570nm for primary amino acids, 440nm for secondary amino acids UV-Vis Detector
Hint: Assume in this case that both Guard and Analytical column are good. For more information, search standard Amino Acid chromatogram.

aflatoxin, Amino Acid Analysis, clean-up, GPC, histamine, mycotoxin, ochratoxin, pickering

New Product Lines from Pickering, October 2009

New Product Lines from Pickering

Mycotoxin product lineMycotoxin product line (PDF)
We are now distributing Mycotoxin Immunoaffinity products for Ochratoxin and Aflatoxin. The performance and batch-to-batch reproducibility of the columns is exceptional and far exceeds that of other manufacturers. The columns can be used for any matrix, from wine and juice, to nuts and grains, to herbs and spices. Contact Sales for more information.
GPC Sample Clean up line
GPC Sample Clean Up Line Products Page
We have a new GPC Sample Clean-up product line! We have both automated and manual GPC cleanup systems and we also have systems that include concentration & solvent exchange, or just GPC. Sample cleanup using GPC is especially useful for fatty matrices, but also perfect for vegetable matter and spices, as well as soil & waste water.

New faster AAA columns Products Page
We now have a Lithium amino acid run which will separate 45 amino acids in 70 minutes for Physiologic fluids, an a new 30-min Sodium amino acid run which will separate the 20 amino acids commonly found in protein hydrolysate samples. These columns are for use with our Pinnacle PCX.
New faster AAA columns

 
Histamine Product Line
Our newly launched Histamine product line consists of Dip-sticks and Elisa kits as well as Post-column derivatization for fast and in-situ testing as well as quick, reproducible, and sensitive methods for follow-up confirmation. Contact Pickering Laboratories at 1-800-654-3330 or sales@pickeringlabs.com for more information!
Amino Acid Analysis, carbamate, glyphosate, HPLC, Ninhydrin, post-column derivatization, Refractive Index Sensitivity, Trione

About Post-Column derivatization analysis for HPLC – Part Three

Detector Considerations

Refractive Index Sensitivity

RI sensitivity applies only to UV-vis detectors. There are two sources of RI noise in post-column applications:

  •  RI discontinuities due to imperfect mixing.
  • RI discontinuities due to temperature gradients in the eluant/reagent stream as it leaves a heated reactor.

In either case, when such inhomogeneities enter the flowcell, they bend light into the wall or off the photomultiplier tube, causing detector noise. The noise usually correlates with the piston cycles of the pumps, thus limiting the detector to low-sensitivity applications.
Most flowcells in modern UV-vis detectors are designed to minimize the effects of RI.

In order to minimize the temperature-related RI effects mentioned above, some manufacturers have a capillary heat exchanger at the flowcell entrance. In some instances this heat exchanger has an internal diameter of 0.12 mm (0.005 inches), which can result in post-column pressures in excess of 42 bar (600 psi). Since this can exceed the pressure rating of a heated reactor made with fluorocarbon tubing, this small-diameter heat-exchanger tube may need to be replaced with a 0.25 mm (0.010 inch) i.d. tube.

Detector Pressure Ratings

When the eluant-reagent stream from the heated reactor reaches the detector, it can release dissolved gas as it cools. The Pickering Laboratories derivatization instruments place a back-pressure of 7 bar (100 psi) on the detector flowcell in order to prevent the formation of bubbles.

  • suppress boiling in the reactor
  • prevent outgassing in the detector flowcell.

The back-pressure regulator can be factory-adjusted to accommodate flowcells with a lower back-pressure rating, depending upon the reactor temperature. but a setting lower than 3.2 5 bar (70 psi) is not recommended for reactor temperatures over 100° C.

Operating an HPLC system with a post-column derivatization system can be as routine as regular LC. The benefits from this LC/post-column combination include minimal sample pre-treatment, greatly improved sensitivity, and enhanced selectivity for compounds that would normally be much more difficult to detect.