The rapid growth of nanotechnology has increased the occupational exposure to nanomaterials. On the other hand, a growing body of evidence considers exposure to these materials to be hazardous. Therefore, it is necessary to examine the effects of occupational exposure to these materials by different methods. Biological monitoring, especially the investigation of oxidative stress induced by exposure to nanomaterials, can provide useful information for researchers. This study systematically reviews studies that have investigated oxidative stress caused by occupational exposure to nanomaterials. The search was conducted on the PubMed, Scopus and Web of Science databases. Of the 266 studies we obtained in our initial search, eventually 11 were included in our study. There is currently no specific biomarker for investigating oxidative stress induced by exposure to nanomaterials. Therefore, the reviewed studies have used different biomarkers in different biological fluids for this purpose. Also, the methods of assessing occupational exposure to nanomaterials in the investigated studies were very diverse. Given the approach of the investigated studies to biomarkers and exposure assessment methods, finding a specific biomarker for investigating exposure to nanomaterials seems unattainable. But reaching a group of biomarkers, to assess exposure to nanomaterials seems more applicable and achievable.

Monitoring the trace amount of chemicals in various samples remains a challenge. This study was conducted to develop a new solid‐phase microextraction (SPME) system (inside‐tube SPME) for trace analysis of n‐hexane in air and urine matrix. The inside‐tube SPME system was prepared based on the phase separation technique. A mixture of carbon aerogel and polystyrene was loaded inside the needle using methanol as the anti‐solvent. The air matrix of n‐hexane was prepared in a Tedlar bag, and n‐hexane vapor was sampled at a flow rate of 0.1 L/min. Urine samples spiked with n‐hexane were used to simulate the sampling method. The limit of detection using the inside‐tube SPME was 0.0003 μg/sample with 2.5 mg of adsorbent, whereas that using the packed needle was 0.004 μg/sample with 5 mg of carbon aerogel. For n‐hexane analysis, the day‐to‐day and within‐day coefficient variation were lower than 1.37%, with recoveries over 98.41% achieved. The inside‐tube SPME is an inter‐link device between two sample preparation methods, namely, a needle trap device and an SPME system. The result of this study suggested the use of the inside‐tube SPME containing carbon aerogel (adsorbent) as a simple and fast method with low cost for n‐hexane evaluation.