#0030 Development of a measurement method to determine the ceiling exposure concentration of ortho-phthalaldehyde handling workers
New Highly Sensitive Method to Detect Low Exposure to a Toxic Medical Disinfectant
ortho-phthalaldehyde (OPA) is widely employed as a sterilant to disinfect medical equipment such as endoscopes. Although OPA is certainly useful, exposure to it can cause eye irritation, respiratory problems, and dermatitis in workers or patients. The American Conference of Governmental Industrial Hygienists has therefore recommended a “threshold limit value-ceiling” for OPA, which specifies the absolute maximum concentration in air to which one should be exposed at any point. This threshold is set at 0.1 parts per billion (or 0.00000001%).
However, this threshold is so low that existing methods do not have the sensitivity to accurately determine the ceiling exposure concentration of OPA. Thus, in our study, we aimed to develop a new highly sensitive sampling and measurement method to detect airborne OPA.
We had previously developed the optimal conditions for the extraction of OPA from 2,4-dinitrophenylhydrazine-silica sampling cartridges, which are used in traditional approaches, using phosphoric acid. We had also established the optimal procedure to prepare OPA samples using these cartridges for analysis via high-performance liquid chromatography (HPLC). In this study, we further developed our method by combining HPLC with tandem mass spectrometry and validating our approach through practical experiments.
We confirmed that, using our technique, OPA samples could be obtained in as little as 18 seconds. With the appropriate concentration of phosphoric acid, more than 93% of the total OPA gathered could be extracted from the cartridge. Moreover, the sampling cartridges were stable and could be stored in a refrigerator for several days. We found that our measurements were repeatable and precise.
In addition, the limit of quantification of our technique was 0.165 nanograms per sample, which was sufficient to determine OPA concentrations at the required safety threshold. Thus, we hope that our novel method could help prevent adverse effects caused by excessive OPA exposure in healthcare workers and patients alike.
Link to the original journal article:
https://onlinelibrary.wiley.com/doi/full/10.1002/1348-9585.12105
Title of the paper:
Development of a measurement method to determine the ceiling exposure concentration of ortho-phthalaldehyde handling workers
Authors:
Shinobu Yamamoto, Akito Takeuchi, Toru Ishidao, Hiroaki Ohkuma, Masayoshi Ichiba, Hajime Hori
