The University of Massachusetts Lowell (UMass Lowell) Toxics Use Reduction Institute's (TURI) Laboratory is performing gravimetric analysis as part of the IEHA's High Performance Cleaning Product (HPCP) testing program to verify the cleaning performance of environmentally preferable products, and equipment.
"The technology available for measuring comparative soil removal continues to advance, and we are pleased to incorporate these testing processes in our HPCP program," says Beth Risinger, CEO and Executive Director of IEHA.
Measurement is performed before and after cleaning using 2" x 4" rectangular test coupons or panels, flat sheets matched to a particular surface's materials of construction, for example, stainless steel, ceramic or glass. Coupons are number-etched for identification.  Coupon testing is performed in triplicate (minimally) to determine cleaning effectiveness. Testing consists of:
(1)          Initial weighing of pre-cleaned coupons by means of an analytical balance (gram weight)
(2)          Applying the appropriate contaminant (oil, grease, soil, etc.) to the surface of the coupons with a hand-held swab in a highly consistent manner
(3)          Re-weighing the artificially-contaminated coupons under the same conditions as (1)
(4)          Performing the actual cleaning trial (entails the primary elements of cleaning such as time, agitation, concentration and temperature, collectively known as TACT)
(5)          Final and third weighing of cleaned coupons under the same conditions as (1)
"Gravimetric analysis using precisely calibrated analytical scales enables us to determine by weight the percentage of soil that was removed from surfaces, and eliminates human error and guesswork," says Jason Marshall, TURI Lab Director. "These devices allow us to determine soil removal with a high level of accuracy."