Evaluation of the Adsorbent Ambersorb XE-347 for Air Sampling of Vinyl Acetate

Abstract

A method for air sampling of vinyl acetate on the adsorbent Ambersorb XE-347 was evaluated. The desorption was performed by solvent extraction (5% methanol in dichloromethane) and the analysis by capillary gas chromatography. Recovery experiments were performed with the adsorbent loaded with 17.5, 175, and 875 μg vinyl acetate per tube (corresponding to 3.5, 35, and 175 mg/m³ air level), 5-L sample volume, 200 ml/min sampling rate, and 20 and 85 percent relative air humidity (RH), respectively. The recoveries were ≥ 95 percent with a standard deviation of 1-2 percent. Storage tests were performed with samples loaded with 175 μg vinyl acetate per tube at three different RH levels (20%, 50%, and 85%). The samples were stored (4, 10, and 14 days) at ambient temperature (21°C) and in a refrigerator (5°C). For the samples loaded at 20 and 50 percent RH, the recoveries were > 86 percent after 14 days' storage. Samples collected at 85 percent RH showed lower recoveries: 66 percent (14 days, 21°C) and 79 percent (14 days, 5°C). When these samples were stored at ambient temperature (2 days) and additionally in a freezer (12 days), the recovery was 82 percent. The conclusion drawn from the study is that the method is suitable for air sampling of vinyl acetate, provided that samples collected at higher RH levels (> 50%) are stored in a freezer prior to analysis.