Application of Needle Trap Device Based on the Carbon Aerogel for Trace Analysis of n-Hexane in Air Samples

Abstract

Occupational exposure to the solvents causes serious risk to human health. Normal hexane (n-hexane) is a solvent used in oil extraction, glues, and cleaners. According to international methods, it is suggested to use a charcoal tube for sampling of n-hexane in the air of workplaces. In this research, the application of a needle trap device containing carbon aerogel nanoparticles (CA-NTD) was investigated in the sampling and analysis of n-hexane in air samples. The NTD was filled with 5 mg of carbon aerogel between two layers of glass wool in a 21-gauge stainless steel needle. Then, the CA-NTD was optimized for n-hexane analysis of the sampling breakthrough, time, and desorption temperature. The performance of this method was confirmed with respect to its accuracy, precision, limit of detection, and limit of quantification. A breakthrough level of n-hexane transmission from the back to front needles occurred in volumes higher than 400 mL. The results showed that, 60-s after inserting the NTD in the injector port, no gas chromatography response was found, and the extraction efficiency was higher than 99%. Moreover, the inter-day and intra-day reproducibility was estimated with a coefficient variation lower than 5%. The detection limits of the CA-NTD were obtained on 0.013 µg L−1. The CA-NTD was found to be an effective active sampler for determining n-hexane in air samples, and also CA-NTD analysis is recommended as an alternative trace analysis method of n-hexane.