HPLC-MS will be better

You should read the review:

Standardised methods for amino acid analysis of food" British Journal of Nutrition , Volume 108 , Issue S2 , August 2012 , pp. S230 - S237

GC/MS needs derivatization. HPLC alone may not be suitable for all AAs because of the detection (no UV absorption for example).

I agree with Saif Saleh Mohsen Ali . GC is a viable option if your components are either a gas or have a boiling point lower than approx. 400°C. Aminoacids will decompose at tempratures between approx. 150-250°C.

Saif Saleh Mohsen Ali, AAs should be derivatized, as I said, they won't survive the GC injection otherwise. AAs are not volatile.

In general, HPLC is the preferred method for measuring amino acids in feed samples since it is more sensitive, versatile, and can measure a broader range of amino acids. HPLC can separate amino acids based on their chemical properties and detect them using UV or fluorescence detectors. On the other hand, GC-MS requires the derivatization of amino acids into volatile compounds, which can limit its accuracy, sensitivity, and selectivity.

Here is a general protocol for measuring amino acids in feed samples using HPLC:

Procedure:

1- Weigh 1 g of feed sample and add it to a 50 mL Falcon tube.

Add 5 mL of 6 M NaOH solution to the tube and mix thoroughly.

2- Incubate the mixture at 110°C for 24 hours.

3- Cool the sample to room temperature and adjust the pH to 9.0 with 2 M NaOH.

4- Add 5 mL of borate buffer solution and mix well.

5- Derivatize the amino acids by adding 1 mL of PITC in ACN (1 mg/mL) to the sample and vortex for 30 seconds.

6- Incubate the mixture at 40°C for 30 minutes.

7- Add 10 mL of water to the sample and vortex for 30 seconds.

Centrifuge the sample at 5000 rpm for 10 minutes.

Inject 20 μL of the supernatant into the HPLC system equipped with a C18 column.

8- Separate the amino acids using a gradient of ACN and water, and detect them using a UV or fluorescence detector.

9- Compare the peak areas of the amino acids in the sample with those in the standard solution and calculate the concentrations of each amino acid in the sample.

Please note that this protocol is a general guideline and may need to be adjusted based on the specific conditions and requirements of your experiment.

Thank you so much for your feedback Saif Saleh Mohsen Ali Jean-François Gal Falco Haarnagel Mohammed Almajidi , I really appreciated it

HPLC-DAD-FL is the most commonly used method for AA (esp in Feed samples).

HPLC-DAD-MS (or with DAD-MS/MS) may also be used and has many benefits due to the multiple dimensions of analysis provided by the different detectors used (but such a system is far more expensive and requires far more experience to use). Most types of GC methods are not applicable to all of the AA's of interest. It must be stated that all types of HPLC/LC-MS AA methods are complex to perform, error prone, require detailed sample prep, frequent maintenance/servicing of the HPLC (and/or MS) system, best performed only by advanced level users. *Amino Acid analysis is not an application well suited to most users as a great deal of technical understanding and experience with the instrument is needed to achieve reliable results.

HPLC

you have to use hplc, because for gc-ms we have to use volatile solutions, and this is not the case.

In general, If there is an absorption peak of specific standard of the specific composition, the HPLC will give better results.

UHPLC and UPLC are convenient for any amino acid analysis, in HPLC it will take almost 60-100 minutes to get your desired amino acid peaks, but in UPLC you get it within 10 minutes with higher resolution.

With HPLC/UPLC derivatization is must to get your desired peak at the desired wavelength.

I agree with Saif Saleh Mohsen Ali

LC-DAD-SM is better for your samples because Gc-MS provides volatile compounds .

Hplc