Abstract
A procedure for quantitating air samples generated at waste sites was developed. A simultaneous direct reading indicator tube system was used that concurrently drew air through up to ten separate colorimetric direct reading detector tubes. The system consisted of two battery operated air pumps, ten detector tubes, and needle valves connected to three way stopcocks that regulated the sample flow through the tubes at approximately 300 milliliters per minute. As the air samples passed through the detector tubes they produced detectable lengths of stain or color change reactions at the minimum contaminant detection limit for each tube. The length of the stain and intensity of color produced in the detector tube was dependent on the rate of contaminant gas flow through the reagent beds. The system provided continuous air flow and a more distinct and clearly defined stained reaction in the detector tubes than when hand operated pumps were used. Activated charcoal filters placed between the detector tubes and the needle valves provided protection against corrosion by reaction products generated by the detector tubes during sampling. Following calibration, appropriate sample volumes were aspirated into each tube and excess samples were directed to the bypass valve by adjusting the stopcock. A single test using this device was completed within 8 minutes. This device was used successfully to detect several esters, aromatic hydrocarbons, ketones, alcohols, aliphatic hydrocarbons, carbon-monoxide (630080), halogenated aliphatic hydrocarbons, amines, ammonia (7664417) and acid vapors. The authors recommend the use of the system for rapid screening of unknown substances at spill scenes or hazardous waste sites.
