X-Ray fluorescence analysis has been used for the quantitative determination of the light elements P, S, and Cl, which are used in the chemical treatment of cotton and cotton fabrics. Determinations of the amounts of resins used in the chemical modification of cotton cellulose and cotton fabrics have become increasingly important with the extensive use of such treatments. Chemical methods for these determinations are frequently time consuming and often lack the required sensitivity. If the resin treatment contains a metallic or nonmetallic element not found in cellulose (as is frequently found in the use of organometallic compounds or of simple inorganic salts and oxides), the amount of resin can be calculated from a determination of the specific element. This approach, in turn, requires a rapid, sensitive, and accurate method for the determination of the selected element. The wet-chemical methods for these elements are difficult and time consuming. X-Ray fluorescence has fulfilled this need and determination of these and other elements is performed on a routine basis. Matrix problems which may arise due to the nature of the cellulose material are circumvented by the use of standard disks, which are prepared by adding known quantities of the element with a cellulose material such as cotton and pressing it into a disk. The x-ray fluorescence measurements yield calibration curves which are linear in the range from 0.03% to 10% concentration of the element in the cotton.
Biagio Piccolo, Donald Mitcham, and Robert T. O'Connor, "X-Ray Fluorescence Method for the Quantitative Analysis of Light Elements in Chemically Treated Cottons and Other Agricultural Products," Appl. Spectrosc. 22, 502-505 (1968)