Planta Med 2008; 74 - PC111
DOI: 10.1055/s-0028-1084629

Evaluation of different analytical methodologies for the analysis of amino acids in plant extracts

M Nasimullah Qureshi 1, G Stecher 1, MA Hashir 1, T Sultana 1, G Abel 2, M Pop 2, GK Bonn 1
  • 1Institute of Analytical Chemistry and Radiochemistry, Leopold-Franzens-University Innsbruck, Innrain 52 a, 6020 Innsbruck, Austria
  • 2Bionorica AG, Kerschensteinerstr. 11–15, 92318 Neumarkt, Germany

The study aimed at the evaluation of different analytical approaches in order to recognize the most suitable technique for qualitative and quantitative analysis of amino acids. Focus within the study was placed on thin layer chromatography (TLC), amino acid analyser and a newly developed mass spectrometric method, i.e. matrix free material enhanced laser desorption ionization time of flight mass spectrometry (mf-MELDI-TOF-MS). Samples employed within the study were standards and water extracts from medicinal plants.

TLC was developed using a mixture of n-BuOH:Acetone:Acetic acid:H2O (35:35:10:20) as mobile phase. The visualization of different amino acids was performed after reaction with ninhydrin solution. Matrix free material enhanced laser desorption ionisation time of flight mass spectrometry (mf-MELDI-TOF-MS) has been utilized for the analysis of amino acids from plant extracts. Within this study, the results of employed amino acids standards and target amino acids from water extracts of Althaeae radix, Taraxacum officinale and Matricaria chamomilla are presented. Within mf-MELDI-MS for different amino acids clear protonated, potassium and sodium adduct signals could be obtained. Quantification of amino acids was performed through amino acid analyser using the ninhydrin post column derivatization method.

Evaluation of all three techniques employed, clearly proved the performance of mf-MELDI-MS for the qualitative analysis of complex mixtures, as targets don't need modification and analysis needs only a few minutes. For quantification, TLC as semi quantitative technique and amino acid analyser with ninhydrin post column derivatization are the methods of choice.

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