氨基酸标准品谷氨酰胺和色氨酸中稳定性检测方案(氨基酸分析仪)

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HITACHIInspire the NextTechnical ReportAS/AAA-015 High-speed Amino Acid Analyzer Stability of Glutamine and Tryptophan In the commercially available mixed standard sample solution used for the amino acidanalysis， glutamine (GluNH2) and tryptophan (Trp) that are considered unstable are notincluded. For the quantitative analysis of those， an analyst adds the separately preparedGluNH2 or Trp standard solution to the commercially available mixed standard sample.Then， to adjust the pH close to that of the mobile phase， the dilution with dilutehydrochloric acid is performed for the analysis. This time， the solution for dissolving GluNH， and Trp to be added and the storage methodwere studied. As a result， the stability was found to be different depending on thecomponents， and the study results are introduced here. L-8900 High-speed AminoAcid Analyzer Verification Method for Stability Table 1 Analytical Conditions (1) Weigh 7.3 mg of GluNH2 and 10.2 mg of Trp (2)Make up the volume to 20 mL with dilutehydrochloric acid (20 mmol/L HCI) or ultrapurewater to prepare the 2.5 pmol/mL solution 3))Store at 4°C or -20°C(4))Perform the step (1) to (3) every 2 weeks (5)After 12 weeks， dilute the solutions that hadbeen prepared with dilute hydrochloric acid to0.1 umol/mL 6) Analyze Column #2622PH 4.6 mm I.D. ×60 mm Guard column #2619 4.0 mml.D. x5 mm Ammonia filtercolumn #2650L 4.6mm l.D. x 40 mm Mobile phase MCI buffer L-8500 PH-Kit* Flow rate 0.40 mL/min Column temperature 57°C Reaction reagent Ninhydrin coloring solution kit for Hitachi* Reaction reagentflow rate 0.35 mL/min Reaction temperature 135°C Detection wavelength VIS 440 nm， 570 nm Injection vol. 20 pL Figure 1 Verification Method * Supplier： Wako Pure Chemical Industries， Ltd. Change When Stored at -20°℃ After Dissolving with Dilute Hydrochloric Acid Figure 2 Chromatogram of StandardSample Immediately After Storage Figure 3 Chromatogram of StandardSample After 12 Weeks Change When Stored at 4C After Dissolving in Ultrapure Water Comparison of Changes Over Time for Different Solutions and Storage Temperatures Based on the peak area obtained immediately after dissolving in ultrapure water， the area ratios (%) were determined. The concentration of glutamine dissolved in dilute hydrochloric acid decreased gradually.However， the change wassuppressed when ultrapure water was used for the dilution (Figure 6). / For tryptophan， regardless of the solutions and storage temperatures， no significant change was observed (Figure 7). Dissolved in ultrapure water， Stored at -20°℃ Dissolved in ultrapure water， Stored at 4°C )Dissolved in dilute hydrochloric acid， Stored at-20°℃ Dissolved in dilute hydrochloric acid， Stored at 4°C Figure 6 Variation with Time for Glutamine )Dissolved in ultrapure water， Stored at -20℃Dissolved in ultrapure water， Stored at 4°C)Dissolved in dilute hydrochloric acid， Stored at-20°C'Dissolved in dilute hydrochloric acid， Stored at 4℃ Figure 7 Variation with Time for Tryptophan NOTE： These data are an example ofmeasurement； the individual values cannot be guaranteed. @Hitachi High-Tech Science Corporation Page. Page.http：//www.hitachi-hitec-science.comCHitachi High-Tech Science Corporation