Salicylate content in blood serum or the like can be spectrophotometrically determined using a new reagent solution. The reagent solution contains ferric ions, tungstic acid, phosphoric acid and a polyoxyethylene/polyoxypropylene block copolymer which is an effectively non-ionic surfactant. Preferably, when human blood sera is used, the standard employed for calibration contains a base so that both the standard and the reagent solution containing unknown are at the same pH. The described technique has the advantages of the Trinder method but does not contain mercuric chloride.
An aqueous reagent system for the quantitative determination of protein is disclosed. The system contains Coomassie Brilliant Blue G-250 dye, a monobasic strong acid having a pK.sub.a of less than 3 (e.g. HCl), a polybasic phosphonic acid (e.g. NTP), a water soluble, non-ionic surfactant characterized as being a block copolymer containing terminal polyethylene oxide segments separated by a polypropylene oxide segment. Preferably the system also contains a small amount of an alcohol such as methanol or ethanol.
A method for detecting the presence of carboxylic acids in a specimen is provided. A specimen is contacted with a developing system containing a metal salt reactive with carboxylic acids present in the specimen to form metal-carboxylic acid complexes. Any such complexes are colorimetrically detected by their activity in catalyzing oxidation of a chromogen such as guaiac. The method is useful in detecting intestinal helminth infestation.
An improved multi-purpose blood diluent is provided which is isotonic, with a neutral pH for avoiding cell volume change. The diluent of the invention provides balance between the effects on cell volume of a preservative for the solution, and the effects of a surfactant. The diluent of the invention is particularly useful as a carrier for blood samples in instruments which automatically provide medical diagnostic determinations of blood samples. The diluent herein includes conventional sodium and potassium chlorides as electrolytes, pH buffers, such as monobasic and dibasic phosphate, and ethylene diamine tetraacetic acid to control and chelate the divalent cations. The balanced preservative-surfactant combination may include, for example, 2-phenoxyethanol with certain ethylene oxide-polypropylene glycol condensation products.
A quantitative colorimetric or spectrophotometric method of determining analyte albumin using a specie specific dye-based color reagent is disclosed. The method utilizes a standard solution comprising an aqueous solution of albumin of different specie than that of the analyte and a water soluble surfactant containing at least one hydrophobic group of contiguous carbon atoms. The surfactant is of a type and present in an amount such that the standard solution mimics, with respect to spectrophotometric response, an aqueous solution of the analyte when the standard solution and the analyte solution contain the same concentrations of albumin and color reagent.
Method, kits and reagents for the simultaneous, kinetic spectrophotometric analysis of blood serum samples for multiple components. Pairs of components which may be simultaneously analyzed are: cholesterol and triglyceride; glucose and urea; uric acid and gamma glutamyl transferase; calcium and magnesium; albumins and total protein.
