# US 2021/0239658 A1 · High-resolution liquid chromatography on the basis of a sawtooth gradient

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- Number: US 2021/0239658 A1
- Document ID: US20210239658A1
- Status: Published application
- Kind: A1
- Application number: 15/734,752
- Filed: 2018-06-06
- Published: 2021-08-05
- Earliest claimed: 2018-06-06
- Assignees: Wacker Chemie AG
- Applicants: Wacker Chemie AG
- Inventors: Bernhard DURNER; Thomas EHMANN
- Web page: https://patentgrep.com/patent/US20210239658A1

## CPC

- G01N 30/34: of fluid composition, e.g. gradient (G01N30/36 takes precedence)
- G01N 30/88: Integrated analysis systems specially adapted therefor, not covered by a single one of the groups G01N30/04 - G01N30/86
- G01N 2030/885: {involving polymers}
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

Polymer makeup is analyzed by performing a liquid chromatographic analysis using a mobile phase containing at least one non-solvent S1 for the polymer and at least one solvent S2 for the polymer, wherein the volume proportion of the solvent S2 varies stepwise during the elution process, and the steps alternate between increasing and decreasing solvent content.

## Claims

### Claim at position 1

-13. (canceled)

### Claim 14

A method for analyzing a polymer sample, the method consisting of performing a liquid chromatography analysis on a chromatography column with a mobile phase comprising a mixture of at least one nonsolvent (S1) and at least one solvent (S2) for the polymer sample, wherein the proportion by volume of S2 in the mobile phase is varied in a stepwise manner during the elution process and that the steps are alternately ascending and descending, wherein either
a) the mobile phase consists of a nonsolvent S1 and a solvent S2 and the composition of the mobile phase is varied over time as follows, with regard to step, time, proportion of S1 and proportion of S2, respectively:
Step x:
t
100 − S2
SP + (x − 1)*B
C · t
100 − S2
SP + (x − 1)*B − A
D · t
100 − S2
SP + (x − 1)*B − A
E · t
100 − S2
SP + x*B
where the parameters A, B, C, D, and E are selected from the following ranges A: 0.01-100% vol % of S2 and B: 0.01-100% vol % of S2 and C: 0-100 and D: 0-100 and E: 0-100; or
b) the mobile phase consists of two nonsolvents S1 and S1′ and a solvent S2 and the composition of the mobile phase is varied over time as follows, with regard to step, time, proportion of S1, proportion of S2, and proportion of S1, respectively:
Step x:
t
0
SP + (x − 1)*B
100 − S2
C · t
100 − S2
SP + (x − 1)*B − A
0
D · t
100 − S2
SP + (x − 1)*B − A
0
0.01
0
SP + (x − 1)*B − A
100 − S2
t
0
SP + (x − 1)*B − A
100 − S2
E · t
0
SP + x*B
100 − S2
where the parameters A, B, C, D, and E are selected from the following ranges A: 0.01-100% vol % of S2 and B: 0.01-100% vol % of S2 and C: 0-100 and D: 0-100 and E: 0-100.

### Claim 15 (depends on 14)

The method of claim 14, wherein the shapes of the steps are columnar, trapezoidal, zigzag or sawtooth in form.

### Claim 16 (depends on 14)

The method of claim 14, wherein the polymer sample is a single polymer.

### Claim 17 (depends on 16)

The method of claim 16, wherein the polymer sample is a polymer selected from the group consisting of polyvinyl chloride, polyethylene, polypropylene, polyvinyl acetate, polycarbonate, poly(meth)acrylate, polystyrene, polyacrylonitrile, polyvinylidene chloride, polyvinyl fluoride, polyvinylidene fluoride, polyvinylidene cyanide, polybutadiene, polyisoprene, polyethers, polyesters, polyamide, polyimide, polysiloxanes, polysilanes, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, polyethylene glycol, and derivatives and copolymers thereof, cellulose, starch, casein, and natural rubber, methylcellulose, hydroxymethyl cellulose, and carboxymethyl cellulose.

### Claim 18 (depends on 14)

The method of claim 14, wherein the polymer sample is a polymer mixture.

### Claim 19 (depends on 18)

The method of claim 18, wherein the polymer sample is a polymer mixture comprising at least two polymers from the group consisting of polyvinyl chloride, polyethylene, polypropylene, polyvinyl acetate, polycarbonate, poly(meth)acrylate, polystyrene, polyacrylonitrile, polyvinylidene chloride, polyvinyl fluoride, polyvinylidene fluoride, polyvinylidene cyanide, polybutadiene, polyisoprene, polyethers, polyesters, polyamide, polyimide, polysiloxanes, polysilanes, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, polyethylene glycol, and derivatives and copolymers thereof, cellulose, starch, casein, natural rubber, methylcellulose, hydroxymethyl cellulose, and carboxymethyl cellulose.

### Claim 20 (depends on 14)

The method of claim 14, wherein the method in alternative a) is repeated at least once, in each case with a different mobile phase, by using the previous solvent as the nonsolvent and selecting a new solvent.

### Claim 21 (depends on 14)

The method of claim 14, wherein the solvent and nonsolvent are independently selected from the group consisting of THF, toluene, cyclohexane, diethyl ether, tetrachloromethane, dichloromethane, chloroform, 1,4-dioxane, N,N-dimethylacetamide, N,N-dimethylformamide, benzyl alcohol, methyl ethyl ketone, ethyl acetate, acetone, acetonitrile, dimethyl sulfoxide, hexafluoroisopropanol, 2-propanol, methanol, water, and mixtures thereof.

### Claim 22 (depends on 21)

The method of claim 21, wherein solvents and nonsolvents are preferably independently selected from the group consisting of THF, hexafluoroisopropanol, methanol, acetone, water, and mixtures thereof.

### Claim 23 (depends on 14)

The method of claim 14, wherein the parameters A, B, C, D, and E are selected from the following ranges:
A: 3.0-12.0% vol % of S2,
B: 0.2-1.0% vol % of S2,
C: 0.5-3.0,
D: 0.5-3.0, and
E: 0.1-2.0.

### Claim 24 (depends on 23)

The method of claim 23, wherein the parameters A, B, C, D, and E have the following values: A: 6.0 vol % and B: 0.2 vol % and C: 1.0 and D: 3.0 and E: 2.0.