Ninhydrin-positive substances testing to pharmacopeia monographs

Published: 17-Jan-2022

Butterworth switches to new amino acid analyser to test ninhydrin-positive substances

Butterworth has updated its procedures for ninhydrin-positive substances testing to make use of a new amino acid analyser purchased and commissioned in 2021, replacing an earlier HPLC post-column method. Analysis of Arginine, Histidine and Tryptophan have already been verified.

In 2014 when the EP moved from TLC to the current HPLC based system, Butterworth had decided to reconfigure an existing HPLC system with a secondary pump and heated reaction coil to carry out the analysis. However, over time the system lacked sensitivity and, under certain circumstances, by-products from the derivatisation process form precipitates, blocked the tubing and caused high back pressures. These problems increased instrument down time due to the need for maintenance. Hence the move to a dedicated Amino Acid Analyser.  In doing so we have seen greater sensitivity and more reliable system.

Ninhydrin-positive substances testing to pharmacopeia monographs

Going forward into 2022, the remaining monograph materials will be verified for other less frequently requested amino acids when asked for by clients. In addition our Projects Department are also currently looking at verifying the same testing in the JP Monograph.

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