Air sampling sorbent tubes have been used for many years in determining concentrations of chemicals in the work environment. The conventional way to desorb analytes from the sorbents involves physical removal and transfer of the sorbent from the tube to a vial containing desorption solution. A new desorption technique, whole tube desorption--which involves adding the glass tube containing the sorbent to the vial containing the desorption solvents--has been evaluated. With this technique there is no transfer of sorbent out of the glass tube. Recovery efficiencies for several chemicals including ethylene oxide, methylene chloride and styrene were comparable to those obtained using traditional solvent desorption procedures. The utilization of this new desorption technique will involve a simple modification in the design of commercially available sorbent tubes so that the front and back sections can be physically separated. This new technique allows for a significant reduction in the time spent in the desorption of air sampling sorbent tubes and easier adaptation to laboratory robotic systems.

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The performances of four formaldehyde monitoring devices were compared in a series of laboratory and field experiments. The devices evaluated included the DuPont C-60 formaldehyde badge, the SKC impregnated charcoal tube, an impinger/polarographic method and the MDA Lion formaldemeter. The major evaluation parameters included: concentration range, effects of humidity, sample storage, air velocity, accuracy, precision, interferences from methanol, styrene, 1,3-butadiene, sulfur dioxide and dimethylamine. Based on favorable performances in the laboratory and field, each device was useful for monitoring formaldehyde in the industrial work environment; however, these devices were not evaluated for residential exposure assessment. The impinger/polarographic method had a sensitivity of 0.06 ppm, based on a 20-liter air sample volume, and accurately determined the short-term excursion limit (STEL). It was useful for area monitoring but was not very practical for time-weighted average (TWA) personal monitoring measurements. The DuPont badge had a sensitivity of 2.8 ppm-hr and accurately and simply determined TWA exposures. It was not sensitive enough to measure STEL exposures, however, and positive interferences resulted if 1,3-butadiene was present. The SKC impregnated charcoal tube measured both TWA and STEL concentrations and had a sensitivity of 0.06 ppm based on a 25-liter air sample volume. Lightweight and simple to use, the MDA Lion formaldemeter had a sensitivity of 0.2 ppm. It had the advantage of giving an instantaneous reading in the field; however, it must be used with caution because it responded to many interferences. The method of choice depended on the type of sampling required, field conditions encountered during sampling and an understanding of the limitations of each monitoring device.

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