Quantification of free Amino Acids

Amino acid analysis service without hydrolysis

Are you looking for quantification of free amino acids in your sample?

Accurate determination of free amino acids is needed for raw materials in food and consumer products. Optimization of fermentation processes and analysis of traces of amino acids are other areas that benefit from accurate determination of amino acids.

Our scientists can help you analyze for free amino acids already present in your sample. Thus the sample is not hydrolyzed prior to amino acid analysis.

If your sample also contains proteins, we include a purification step to remove proteins prior to the analysis.

This is what our service includes:

  • First step is removal of proteins by precipitation prior to analysis.
  • (No hydrolysis of sample).
  • Next, we perform ion exchange chromatography on an amino acid analyzer.
  • Quantification of 20 amino acids with an accuracy of +/- 10%.
  • We deliver a report within 4-8 days.

Do you need to quantify the total protein or purified protein? Then you should have a look at our other services for quantification of protein.

Do you need a high accuracy?

If you need a higher accuracy than +/- 10%, we can perform triplicate analysis for very accurate protein/peptide concentration determination.


We present results in easy-to-understand reports in  just 4-8 days

Our reports present your data in nice tables and graphs. Take a look at the pictures below for examples on how we present your analysis results.

Fast and easy quantification of protein

PICK ‘n POST™ quantification of free amino acids

  • Removal of proteins prior to analysis
  • No hydrolysis of sample
  • Quantification of 20 standard amino acids
  • Accuracy within +/- 10%


Fast and Easy
Will be delivered in 4-8 days
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Technical details

This Amino acid analysis refers to the method used to quantify free amino acids.
The normal 20 amino acids are detected and other unusual amino acids are also detected including hydroxyproline and hydroxylysine.

  • Sample preparation including removal of protein material
  • HPLC analysis
  • Data calculation

The analysis is performed on a BioChrom +30 amino acid analyser by ion-exchange chromatography with post-column derivatization using ninhydrin. All amino acids except Proline (440 nm) are monitored at 570 nm.

Sample preparation
Solid material:
A specific amount of sample is placed in an Eppendorf tube and dissolved in aquas solution. Protein and other high molecular weight molecules are removed by acetone precipitation. The supernatant is concentrated by speed vac and redissolved in loading buffer, before being loaded in fixed amount onto the amino acid analyser.

Liquid material:
After precipitation the test sample is dried in vacuum and the sample is dissolved in loading buffer (sodium Citrate pH 2.20) including a fixed amount of sarcosine (Sar). This is used as an internal standard to correct for changes in reagent stability and flow rates, and the variation for each sample should not exceed 5%.

Calibration of Instrument
A standard mixture of amino acids is analyzed at 3 different concentrations levels (double determination) to show linearity within the measurement range (700 to 2800 pmol). A plot is made showing peak area versus known concentration of each standard solution. The r-value of the calibration has to be better than 0.999 (proline is accepted at 0.995 due to lower signal/noise). The instrument is linear to 5600 pmol and usually up to ~20 nmol. Depending on the amino acid residue, the signal goes into saturation around 25-35 nmol.

Accuracy & Precision
For each batch run we include a duplicate analysis of a standard Amino acid quality control standard. The results are used to determine the precision and the accuracy of the test. The precision should be below 5% and the accuracy within 15%.

Data calculations
A standard amino acid solution is analyzed for each 5 samples, and based on at least two runs, a compensation factor is calculated to correct for ninhydrin activity. Each amino acid in the sample is corrected by this compensation factor.

Sample requirements

Sample Purity
Most samples that contain free amino acids can be analyzed.
Avoid high salt concentrations.
Buffer that contain high amounts of primary amines, e.g. TRIS or glycine, may interfere with the nihydrin reaction and quantification of specific amino acids

Sample type and amount
Samples can be provided as solid lyophilized powder or as liquid.

Provide 50-100 micro-liters (or more) of liquid material at a minimum concentration of 0.1 micro-gram per micro-liter or higher.
Solid material should be provided in sufficient amount for accurate weighing of samples at Alphalyse (mg material).

Unstable samples should be shipped refrigerate to +4°C as cold shipment.

Sample shipment

shipping option
Ship your protein samples by a courier company of your own choice

Place your samples into micro tubes and pack in a suitable transport box.

  • Contact a courier company of your choice (FedEx, UPS, DHL, TNT, World Courier etc.). Use the following sentence to describe the content: “Protein material – Non-toxic, non-hazardous, for research purpose only“.
  • Use cool packs or cooling units if your samples should be stored below 5°C/40°F
  • Ship the samples to the office closest to you (Canadian customers, please ship to Europe):
Customers in the USA
Alphalyse, Inc.
200 Page Mill Road, Suite 100
Palo Alto, CA, 94306
Att: Jette Williams
Tel: (650) 543-3193
Customers outside of USA
Alphalyse A/S
Unsbjergvej 4 D
DK-5220, Odense
Att: Anette Rasmussen
Tel: +45 6310 6500
shipping option
Order a prepaid FedEx Air Waybill < 1 lb./ 500g

A prepaid FedEx Air Waybill can be used for fast and easy shipment of samples in packages up to 1 lb./ 500g.
We will generate a prepaid Air Waybill, prefilled with the correct information, and send it to you by e-mail (PDF-format) within 24 hours.
Then follow these simple instructions:

  • Place your samples into micro tubes. Pack in suitable transport box.
  • Print the PDF document and stick it on the transport box or just hand it to your FedEx officer upon pickup.
  • Call to request a pickup from your local FedEx office.

If you plan to send your samples stored at room temperature, this option is usually the right choice. If you fill your box with cooling packs, the weight will most often exceed 1 lb./500g.

shipping option
Order a prepaid FedEx Air Waybill < 10 lb./5kg (e.g. for packages with cooling packs)

This prepaid FedEx Air Waybill can be used for shipment of samples in packages up to 10 lb./ 5kg, with or without cooling packs.
We will generate a prepaid Air Waybill, prefilled with the correct information, and send it to you by e-mail (PDF-format) within 24 hours.
Then follow these simple instructions:

  • Place your samples into micro tubes. Pack them in a suitable transport box. Fill with cooling units/cold packs.
  • Print the PDF and stick it on the transport box or just hand it to your FedEx officer upon pickup.
  • Call to request a pickup from your local FedEx office.

If you plan to fill your transportation box with cooling packs, select this shipping option.

shipping option
Get a quote for shipment by World Courier

The World Courier service can be used for shipment of samples of all types. If you select this option, we will contact you to provide a quotation based on location and shipping conditions. You will receive a prepaid Air Waybill which will be invoiced together with your analysis results. This is usually a good option if FedEx does not service your location.
With the prepaid World Courier service you get:

  • GxP compliant processes to ensure maximal security and traceability
  • Door-to-door solution on a dedicated vehicle
  • Possibility of providing qualified packaging, temperature monitoring and dry ice
  • Shortest possible transit-time through “next flight out”-procedure
  • Customs clearance and help with paperwork

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