In quality control, high reproducibility of analytical methods is essential in order to be able to make reliable statements about the obtained results.
The following example of the analysis of three pure substances shows that the amino acid analyzer ARACUS is suitable for use in quality control due to its very low standard deviation of less than 0.85 %. In this way it makes an important contribution to ensuring defined quality requirements.
Reproducibility and precision are critical in regulated industries such as pharmaceuticals, food production, and biotechnology, where analytical variability can lead to non-compliance with Good Manufacturing Practices (GMP) and impact product safety (Wang et al., 2020).
Sample Preparation and Analysis
Leucine solution: weight 131.1 mg Leu into a 100 mL volumetric flask and refill to the measuring mark with 1N HCl (Leu concentration 10 µmol/mL) and shake. After that diluted the solution 1:100 with 1N HCl (Leu concentration 100 nmol/mL).
Glutamic Acid solution: weight 147.1 mg Glu into a 100 mL volumetric flask and refill to the measuring mark with 1N HCl (Glu concentration 10 µmol/mL) and shake. After that diluted the solution 1:100 with 1N HCl (Glu concentration 100 nmol/mL).
The preparation of calibration standards using pure amino acid substances is a common approach to ensure traceability and accuracy in quantitative amino acid analysis (Cohen & Michaud, 1993).
Method amino acid analysis
The samples were analyzed by the Amino Acid Analyzer ARACUS, manufactured and distributed by membraPure GmbH worldwide. ARACUS is using the classic routine analysis of amino acids by post-column derivatization with ninhydrin and the detection at 570 nm. The results were evaluate and calculated by the software aminoPeak and the use of a Leu-standard solution Glu-standard solution (purchased by Bachem) (100 nmol/mL).
Post-column ninhydrin derivatization remains a gold standard in amino acid analytics due to its high sensitivity and selectivity for primary and secondary amines, producing highly reproducible chromatographic peaks (Rogers et al., 2020).
Figure 1: Amino Acid Analyzer ARACUS
Precision
The precision of the method was determined by repeatability (intra-day). The intra-day precision was calculated as the relative standard deviation RSD (coefficient of variation CV %) of results from ten runs of the sample during the same day.
Table 1: Amino Acid Leucine and Glutamin acid in a solution of 100 nmol/mL.
