Variability in Surface Infrared Reflectance of Thirteen Nitrile Rubber Gloves at Key Wavelengths for Analysis of Captan

• Published in: Applied spectroscopy 2007-02, Vol.61 (2), p.204-211
• Main Authors: Phalen, R. N., Hee, Shane S. Que
• Format: Article
• Language: English
• Subjects: Captan - analysis; Elastomers - chemistry; Fungicides, Industrial - analysis; Gloves, Protective; Humidity; Indicators and Reagents; Nitriles - chemistry; Spectrophotometry, Infrared; Spectroscopy, Fourier Transform Infrared; Temperature
• ISSN: 0003-7028; 1943-3530
• DOI: 10.1366/000370207779947666

The aim of this study was to investigate the surface variability of 13 powder-free, unlined, and unsupported nitrile rubber gloves using attenuated total reflection Fourier transform infrared (ATR-FT-IR) spectrophotometry at key wavelengths for analysis of captan contamination. The within-glove, within-lot, and between-lot variability was measured at 740, 1124, 1252, and 1735 cm−1, the characteristic captan reflectance minima wavelengths. Three glove brands were assessed after conditioning overnight at relative humidity (RH) values ranging from 2 ± 1 to 87 ± 4% and temperatures ranging from −8.6 ± 0.7 to 59.2 ± 0.9 °C. For all gloves, 1735 cm−1 provided the lowest background absorbance and greatest potential sensitivity for captan analysis on the outer glove surface: absorbances ranged from 0.0074 ± 0.0005 (Microflex) to 0.0195 ± 0.0024 (SafeSkin); average within-glove coefficients of variation (CV) ranged from 2.7% (Best, range 0.9–5.3%) to 10% (SafeSkin, 1.2–17%); within-glove CVs greater than 10% were for one brand (SafeSkin); within-lot CVs ranged from 2.8% (Best N-Dex) to 28% (SafeSkin Blue); and between-lot variation was statistically significant (p ≤ 0.05) for all but two SafeSkin lots. The RH had variable effects dependent on wavelength, being minimal at 1735, 1252, and 1124 cm−1 and highest at 3430 cm−1 (O–H stretch region). There was no significant effect of temperature conditioning. Substantial within-glove, within-lot, and between-lot variability was observed. Thus, surface analysis using ATR-FT-IR must treat glove brands and lots as different. ATR-FT-IR proved to be a useful realtime analytical tool for measuring glove variability, detecting surface humidity effects, and choosing selective and sensitive wavelengths for analysis of nonvolatile surface contaminants.