Solvent exposures additional readings

Rotogravure printing is an example of a proeess industry with solvent exposures. The process is, in principle, closed but emissions take place fi om the openings for the paper web. The workers do not need to stay in the immediate vicinity of the emission sources but can often spend most of their time in the clean control room. Thus, the workers exposure levels depend mainly on their moving pattern during the work shift. In addition, the emission rate depends on the production rate, i.e., on the consumption rate of the solvent (toluene). Stationary sampling can be applied for exposure assessment when it is combined with questionnaire on use of time in various areas. This can be done with a direct-reading instrument because the airborne concentration level remains quite stable. ... 

Solutions and extracts of lipid for the test should be protected from undue exposure to light and air before use in order to prevent deterioration of the existing carbonyl compounds as well as further oxidation of the lipid. The solvents must be of high purity to eliminate any interference from existing carbonyls. Fading of color for the test sample occurs after the addition of the alkanolic base solution. For this reason, absorbance readings should be read exactly 10 min after the alkali addition. If the analysis is performed <1 hr after preparation of the sample, data obtained are reliable. 

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