A neutron activation method for soil removal measurements: A comparison of the reflectance method and the neutron activation method

A nondestructive neutron activation analysis technique has been developed to determine the amt of particulate kaolinite clay soil removed from cotton fibers during a wash cycle. Neutron bombardment of aluminum, present as a constituent of the kaolinite lattice structure, produces short-lived aluminum-28. The amt of particulate soil present on a piece of cotton cloth before and after the wash cycle is determined by γ scintillation counting of the aluminum-28, thus providing an absolute method for the determination of the percentage of soil removed. A comparison of this method with the reflectance method has been made, and equations relating reflectance to clay concn for washed and unwashed soiled cloths have been developed for a given surfactant. It was found that the relationship of the concn of the soil on the test cloths and the measured reflectance depends upon whether the cloth has been washed or unwashed. The validity of the applicability of the Kubelka-Munk equation relating reflectance to soil content on cotton fabric has been experimentally confirmed for soiled cloths have high reflectivity. Presented in part at the AOCS Meeting, Minneapolis, 1963, and at the 15th Annual Chemistry Conference, Kansas City Sec., ACS.