Stability of the blue color formed in the proposed limit test using genipin. The time zero was counted after the reaction was heated for 5 min and then cooled on ice for 1 min.

 
 
  Part of: Thanayutsiri T, Patrojanasophon P, Opanasopit P, Ngawhirunpat T, Rojanarata T (2024) A novel, green and affordable semi-quantitative limit test for 2-aminobutanol impurity in ethambutol hydrochloride bulk and tablets. Pharmacia 71: 1-7. https://doi.org/10.3897/pharmacia.71.e124137