Personal Monitoring for Formaldehyde Using an Activated 13X Molecular Sieve Tube

Abstract

A sampling method for formaldehyde exposure monitoring using activated 13X molecular sieves has been developed. The collection of formaldehyde on this solid sorbent is by physical adsorption. Sampling tubes containing 13X molecular sieves were tested for the stability of the collected samples stored at room temperature or refrigerated. Following tube/pump sampling, formaldehyde was desorbed with water and analyzed by colorimetrie methods such as chro-motropic acid, modified pararosaniline, or MBTH. The presence of phenol or isopropyl alcohol in the atmosphere did not change the sampling efficiency of the 13X tubes. Molecular sieves are known to be affected by the water content in the air. The validation of 13X sampling tubes included breakthrough studies at various relative humidity levels. The performance of the activated 13X tube was tested under laboratory conditions as well as in the actual occupational exposure settings. Field sampling compared the 13X tube samples with water in impingers as the independent method. The relationship between the two methods is presented by means of a linear regression analysis. The correlation coefficient between these two sampling methods was 0.975. Janko, M.; McCarthy, K.D.; Li, S.M.; Graf, N.M.; Rossing, G.D.: Personal monitoring for formaldehyde using an activated 13X molecular sieve tube.