Manik L Das

US Patent:

40308855, Jun 21, 1977

Filed:

Sep 11, 1975

Appl. No.:

5/612300

Inventors:

Manik L. Das - Crestwood MO

Assignee:

Sigma Chemical Company - St. Louis MO

International Classification:

G01N 3316

US Classification:

23230B

Abstract:

An improved azobilirubin determination procedure utilizes a stable, dry lyophilized reagent. Dissolving the dry reagent in dilute hydrochloric acid produces a diazo reagent solution which is stable for several days. Cysteine hydrochloride may be added to the assay mixture to destroy excess diazo reagent, stabilize the final color, and remove interfering metal ions.

US Patent:

42115310, Jul 8, 1980

Filed:

Apr 20, 1979

Appl. No.:

6/031773

Inventors:

Manik L. Das - Ballwin MO

Assignee:

Sigma Chemical Company - St. Louis MO

International Classification:

G01N 3316
G01N 2122
G01N 3102

US Classification:

23230B

Abstract:

A total cholesterol method includes the steps of (1) precipitation of serum proteins with a reagent containing ferric chloride in propionic acid, (2) color formation by heating aliquots of supernatant with propionic-sulfuric acid reagent, and (3) measurement of color intensities of test and standard reaction mixtures at 563 nm.

US Patent:

39648656, Jun 22, 1976

Filed:

Jan 30, 1975

Appl. No.:

5/545298

Inventors:

Manik L. Das - Crestwood MO

Assignee:

Sigma Chemical Company - St. Louis MO

International Classification:

G01N 2120
G01N 3316

US Classification:

23230B

Abstract:

A preweighed vial of lyophilized methemoglobin (ferrihemoglobin) provides a simple, stable, reproducible standard for colorimetric determination of total hemoglobin concentration in whole blood by the cyanmethemoglobin method. Conversion of the standard and of hemoglobin in blood samples to cyanmethemoglobin is accomplished with Drabkin's solution reconstituted from a dry powder and having an added non-ionic surface active agent (Brij-35). Color intensity is measured at 540 m. mu.

US Patent:

39855066, Oct 12, 1976

Filed:

Jul 11, 1975

Appl. No.:

5/595239

Inventors:

Manik L. Das - Crestwood MO

Assignee:

Sigma Chemical Company - St. Louis MO

International Classification:

G01N 2102
G01N 3316

US Classification:

23230B

Abstract:

A stable reagent for use in a rapid and sensitive globulin estimation procedure consists of 60-70 volumes of glacial acetic acid, 1-20 volumes of monomethyl ether of ethylene glycol, 5-15 volumes of phosphoric acid, 5-15 volumes of sulfuric acid, 0. 2-0. 6 volumes of twenty percent glyoxylic acid in aqueous solution, and 0. 4-1. 2 volumes of ten pecent ferric chloride hexahydrate in aqueous solution. The reagent is far more stable, sensitive, and tolerant of water in the reaction mixture than previously known reagents used in the glyoxylic reaction.