Application of Cryogenic Technologies in Sample Preparation for Occupational Exposure to Chemical Contaminants: A Systematic Review

Abstract

Cryogenic technologies have emerged as promising sample preparation techniques for preserving sample integrity and improving analytical performance in occupational exposure assessment. However, evidence regarding their application in occupational exposure monitoring remains scattered and has not been systematically synthesized. A systematic literature review was conducted in 2025 to evaluate the application of cryogenic technologies in sample preparation for occupational exposure assessment of chemical contaminants. The review followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Searches were performed in Scopus, PubMed, Web of Science, and Google Scholar without time restrictions. Studies published in English and Persian were screened based on predefined eligibility criteria. The methodological reliability of toxicological studies was assessed using the Toxicological data Reliability Assessment Tool. Of 862 retrieved records, 18 studies were included. The included studies investigated four cryogenic technologies: Cryo-Electron Microscopy (Cryo-EM), Cryo-Trapping/Cryo-Focusing, Cryo-Grinding, and Cryo-Milling. Cryo-Trapping/Cryo-Focusing was the most frequently applied technique, whereas Cryo-Milling and Cryo-EM were reported only in a limited number of occupational exposure studies. Most applications focused on volatile organic compounds in air, blood, urine, and standard solutions. Cryogenic technologies were associated with improved sample preservation and analytical sensitivity, although methodological heterogeneity limited comparison across studies. Cryogenic technologies represent valuable complementary approaches for sample preparation in occupational exposure assessment. However, current evidence remains limited and heterogeneous, emphasizing the need for standardized studies to establish their broader applicability in occupational hygiene and toxicology.