Abstract: The present invention concerns a method of enzymatically determining the pH of a specimen (e.g., a solution or a biological fluid) and a kit for conducting the method. The present method involves mixing (1) a specimen with (2) an enzyme and (3) one or more substrates for the enzyme in a buffered solution having a pH effective to provide a direct proportional relationship between the activity of the enzyme and the pH of the specimen; determining the activity of the enzyme; and correlating the activity of the enzyme to the pH of the specimen. Each of the sample, the enzyme, the substrate and the buffered solution is present in an amount effective to provide the direct proportional relationship between the activity of the enzyme and the pH of the specimen.

Abstract: The present invention concerns a method of enzymatically determining the pH of a specimen (e.g., a solution or a biological fluid) and a kit for conducting the method. The present method involves mixing (1) a specimen with (2) an enzyme and (3) one or more substrates for the enzyme in a buffered solution having a pH effective to provide a direct proportional relationship between the activity of the enzyme and the pH of the specimen; determining the activity of the enzyme; and correlating the activity of the enzyme to the pH of the specimen. Each of the sample, the enzyme, the substrate and the buffered solution is present in an amount effective to provide the direct proportional relationship between the activity of the enzyme and the pH of the specimen.

Abstract: Novel derivatives of phencyclidine are provided as precursors for conjugating to antigenic proteins for the preparation of antibodies which bind to phencyclidine or conjugation to enzymes for use as reagents in immunoassays. The combination of the antibodies and enzyme conjugates provide a sensitive and rapid assay for phencyclidine.

Abstract: Improved methods for determining very low concentrations of substances present in fluid samples are provided by employing light emitting tracer compounds and (1) counting the photons emitted therefrom while discriminating against noise, nonspecific light, and quenching effects of the sample, or (2) counting the photons emitted therefrom over a predetermined integrated light flux, or a combination of (1) and (2). Further, novel fluorescently labeled low molecular weight antigens are provided which can be employed in competitive binding techniques in which the above described photon counting methods are useful. A homogeneous competitive binding assay, employing photon emitting tracer materials, which eliminates the need for separating bound from unbound materials is also provided. Finally, a modified enzyme amplification technique is set forth employing enzymes active in the bound phase to provide assay techniques useful for extremely low concentration assays.