Apparatus for Sampling Surface Contamination

Tag : fabric sample

An apparatus denoted a swab device has been developed as aconvenient means of acquiring samples of contaminants from surfacesand suspending the samples in liquids. (Thereafter, the liquids canbe dispensed, in controlled volumes, into scientific instrumentsfor analysis of the contaminants.) The swab device is designed soas not to introduce additional contamination and to facilitate,simplify, and systematize the dispensing of controlled volumes ofliquid into analytical instruments.
The use of currently commercially available contamination-samplingdevices involves significant mechanical manipulation of samples andliquids, and there is no provision for systematic dispensing ofcontrolled volumes of liquid into analytical instruments: A typicaluse involves wiping a surface of interest with a standard implementresembling a cotton swab. The implement is then placed into avolume containing the liquid in which the sample is to besuspended. Ultimately, the liquid must be extracted from thisvolume and dispensed into an analytical instrument by use of apipette. The swab device is a single apparatus into which arecombined all the equipment and materials needed for samplingsurface contamination. The swab device contains disposablecomponents stacked together on a non-disposable dispensing head.One of the disposable components is a supply cartridge holding asufficient volume of liquid for one complete set of samples. (Theliquid could be clean water or another suitable solvent, dependingon the application.) This supply of liquid is sealed by Luervalves.
At the beginning of a sampling process, the user tears open asealed bag containing the supply cartridge. A tip on thenondisposable dispensing head is engaged with a Luer valve on oneend of the supply cartridge and rotated, locking the supplycartridge on the dispensing head and opening the valve. A bagcontaining a disposable swab tip is opened, and the end of thesupply cartridge opposite the aforementioned end is engaged withthe swab tip and rotated, opening a valve.
The swab tip includes a fabric swab that is wiped across thesurface of interest to acquire a sample. A sealed bag containing adisposable dispensing tip (not to be confused with thenon-disposable dispensing head) is then opened, and the swab tip ispushed into the dispensing tip until seated. The dispensing headcontains a piston that passes through a spring-loaded lip seal. Theair volume displaced by this piston forces the liquid out of thesupply cartridge, over the swab, and into the dispensing tip. Thepiston is manually cycled to enforce oscillation of the air volumeand thereby to cause water to flow to wash contaminants from theswab and cause the resulting liquid suspension of contaminants toflow into the dispensing tip. After cycling several times to ensureadequate mixing, liquid containing the suspended contaminant sampleis dispensed through the dispensing tip in 25- μL incrementsinto an analytical instrument. The disposable components are thenremoved from the dispensing head. Thereafter, the dispensing headcan be reused with a fresh set of disposable components.
This work was done by Mark Wells of UAH for Marshall Space FlightCenter. For further information, contact Sammy Nabors, MSFCCommercialization Assistance Lead, at This e-mail address is being protected from spam bots, you needJavaScript enabled to view it Refer to MFS- 32560-1.