Spectrophotometric method for structural analysis of organic compounds, polymers, nucleotides and peptides

• US 5,550,630 A
• Filed: 03/19/1993
• Issued: 08/27/1996
• Est. Priority Date: 03/19/1993
• Status: Expired due to Fees

• Current Assignee: The United States of America As Represented By The Secretary of Agriculture
• Original Assignee: United States Department Of Agriculture
• Inventors: Chrastil, Joseph
• Primary Examiner(s): Hille, Rolf
• Assistant Examiner(s): OSTROWSKI, DAVID M
• Application Number:
  US08/034,919
• Time in Patent Office: 1,257 Days
• Field of Search: 356/300, 356/319, 356/320
• US Class Current: 356/300
• CPC Class Codes: G01N 21/31 Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry G01N21/72 takes precedence

Abstract

A method for analyzing the structures of chemical organic compounds, polymers, polynucleotides and peptides is disclosed. The method uses the integrated intensity of spectral light absorption in wide or narrow regions of the ultraviolet and/or visible spectrum and relates these parameters additively to the structural characteristics of the analyzed chemical compound. For the analysis of polymers, nucleotides and/or peptides the integrated intensities of spectral absorption are used sequentially in narrow regions of the ultraviolet light which enables the determination of the molecular weight and the complete amino acid composition of the analyzed compound. All these procedures are interconnected in an automatic spectrophotometric structural analyzer.

Claims

1. A method for determining one or both of the structure or molecular weight of a chemical compound selected from the group consisting of organic compounds, polymers, polynucleotides and polypeptides, comprising:

(a) providing a sample of said chemical compound in a spectrophotometer;

(b) passing a light beam at a first wavelength λ

_l within the UV or visible spectra from said spectrophotometer through said sample;

(c) measuring the absorbance of said sample at λ

_l ;

(d) repeating steps (b) and (c) at a plurality of different wavelengths from λ

_l to λ

_m within the UV or visible spectra and wherein m is an integer greater than one, to measure the absorbance of said sample at each said wavelength;

(e) determining the spectrosum from the absorbance measured in (c) and (d);

(f) determining one or both of the structure or molecular weight of said chemical compound from said spectrosum;

wherein said spectrosum is determined as ##EQU8## wherein S.sub.Σ

is the spectrosum, ε

is the extinction coefficient, and q is an arbitrary constant.

2. A method as described in claim 1 wherein said chemical compound is dissolved in a solvent.

3. A method as described in claim 2 wherein said solvent is selected from the group consisting of water, alcohols, buffers, acids and alkali.

4. A method as described in claim 1 wherein said chemical compound is an organic compound.

5. A method as described in claim 4 wherein λ

_l is about 200 nm and λ

_m is about 800 nm.

6. A method as described in claim 1 wherein said chemical compound is a polymer, polynucleotide or polypeptide.

7. A method as described in claim 1 wherein said sample of said compound is substantially pure.

8. A method as described in claim 1 wherein said sample of said compound is pure.