Environmental analysis in the workplace; development of a rapid, sensitive ELISA for monitoring airborne alcalase

• Published in: Analytica chimica acta 1995-11, Vol.316 (2), p.247-252
• Main Authors: Rowell, F.J., Cumming, R.H., Nitescu, I.
• Format: Article
• Language: English
• Subjects: Alcalase; Applied sciences; Atmospheric pollution; Biosensors; ELISA; Environmental analysis; Exact sciences and technology; Health and safety; Immunoassay; Indoor pollution and occupational exposure; Pollution
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/0003-2670(95)00368-A

Alcalase, in common with other proteases is a respiratory sensitiser and long term and short term occupational exposure limits of 60 ng m−3 for periods of 8 h and 15 min respectively have been set for workers who may inhale these proteases in the work-place. Polyclonal antibodies have been raised in rabbits that specifically recognise alcalase. These have been purified using immunoaffinity chromatography and the resulting anti-alcalase antibodies used with alkaline-phosphatase labelled anti-rabbit antibodies to generate a single reagent for use in a competitive ELISA for alcalase that can be used in a rapid semi-quantitative mode to screen samples from conventional filters following monitoring of worker exposure. Presence of alcalase in excess of the occupational exposure standard (OES) results in a lack of colour at the endpoint of the assay while samples with levels less than the OES produce a yellow colour. The ELISA can process 45 samples in duplicate in 60 min. The limit of detection of the assay is 1 pg ml−1 in a 50 μl sample volume. The assay has good precision with coefficients of variation less than 10%. and is better suited than current colorimetric enzyme assays for use on site by semi-skilled operatives immediately following the monitoring period when exposure of workers above the OES can be rapidly ascertained and action taken.