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

Abstract

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 degrees 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 < or = 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 real-time analytical tool for measuring glove variability, detecting surface humidity effects, and choosing selective and sensitive wavelengths for analysis of nonvolatile surface contaminants.

Polymer properties associated with chemical permeation performance of disposable nitrile rubber gloves

“…Peak absorbance was evaluated in this study as a comparative measure of these two components. Based on the findings of this study, future work using known formulations and/or reference standards would be effective, especially with the use of attenuated total reflectance‐Fourier transform infrared (ATR‐FTIR) spectroscopy …”

“…Polymer uniformity was characterized using a previously described and published ATR‐FTIR spectroscopy method . ATR‐FTIR characterization of polymer uniformity was conducted at 2237 ± 2 cm −1 , with 4 cm −1 resolution and 32 scans.…”

“…Infrared spectra were collected for both the outer and inner surfaces of the glove samples. Based on previous studies, the manufacturer's specifications for the ZnSe crystal, and the estimated material compression during testing, the estimated depth of penetration using this method was about 25%. A coefficient of variation (CV) was calculated for all measurements combined ( n = 60).…”