Abstract: A test method and device employ a matrix to which is covalently bonded a second component of a two component dye system. Color is formed when the first component, which may be the analyte or another dye component, covalently couples to the second component. The color formed is covalently immobilized to the matrix. A preferred second component, 5-amino-2-naphthalene sulfonic acid, is covalently bonded via the amino group and forms a colored covalent adduct with oxidized 4-aminoantipyrine. Another preferred second component is diazotized para-aminoaniline, which is covalently bonded via the amino group and forms a colored covalent adduct directly with bilirubin.

Abstract: An improved chromatographic device and method for quantitating the activity of an enzyme utilizes a bibulous test strip as the stationary phase, an aqueous solution as the mobile phase, and a chromophore as the indicator. The enzyme activity is quantitated by transforming a substantially depletable amount of a chromogenic substrate from soluble chromogen to insoluble chromophore as the mobile phase advances, whereupon the insoluble chromophore becomes immobilized on the test strip to produce a column of color. The length and/or the intensity of the column of color are related to the activity of the enzyme. The present invention is useful for the direct determination of enzyme-analytes and for the indirect determination of analytes which can be coupled to an enzyme.

Abstract: An article is disclosed which comprises fibrous material which has been chemically modified such that the material's cutability using ultrasonic energy becomes facile and the material can be cut into a predetermined shape using ultrasonic energy. The article may additionally comprise fibrous material disposed between first and second fusible materials, wherein at least one of the fusible materials includes means for defining a selected line of cut, and ultrasonic energy directed through the materials along the means for defining a selected line of cut will effect cutting of the fibrous material and fusion of the fusible materials.

Abstract: A method for cutting fibrous materials using ultrasonic energy involves chemically modifying a fibrous material prior to the application of ultrasonic energy. Preferred fibrous materials include cellulose materials and its derivatives, such as, paper. Chemical modification includes oxidation or hydrolysis. Also disclosed is a test device made according to the method. The invention allows for the fusing of plastic and the simultaneous cutting of a chemically modified fibrous material along the line of fusion.