Methods for preparing liquid mixtures

Patent metadata

Field	Value
Publication number	US-10422776-B2
Application number	US-201515309725-A
Country	US
Kind code	B2
Filing date	May 8, 2015
Priority date	May 9, 2014
Publication date	Sep 24, 2019
Grant date	Sep 24, 2019

Abstract

A method of preparing a liquid mixture for use in a liquid chromatography system is provided. The mixture comprises one or more acids, one or more bases, one or more solvents and water, and the method comprises the steps of: calculating pH and/or solvent concentration at a particular time t from a user-determined gradient function; and, based on the values obtained, calculating percent acid, percent base, percent solvent and percent water in the liquid mixture at time t. A liquid chromatography system incorporating such method is also provided.

First claim

What is claimed is:

1. A method of preparing a liquid mixture, the mixture comprising an acid solution comprising a volatile acid, a base solution comprising a volatile base, a solvent comprising an organic solvent, and water, the method comprising:
i) calculating with a processor pH and/or solvent concentration at a particular time t from a user-determined gradient function;
ii) based on the values obtained in step (i), calculating with a processor percent acid solution, percent base solution, percent solvent and percent water in the liquid mixture at time t; and
iii) controlling with a machine a liquid mixture preparation device that comprises a mixed liquid outlet port and a plurality of inlet ports connected to component sources of the acid solution, the base solution, the solvent, and the water, wherein relative component proportions are supplied through the inlet ports of the liquid mixture preparation device and are controlled as a function of time t using the percent acid solution, percent base solution, percent solvent and percent water values calculated in ii).

2. The method according to claim 1 , wherein the gradient function is based on the following equation:
y=y s +( y n −y s )×fraction  (equation 1)

where y is selected from the group consisting of pH and solvent concentration, y s is the value at time 1 and y n is the value at time 2 .

3. The method of claim 1 , wherein the solvent includes one or more of acetone, acetonitrile, methanol, ethanol, n-propanol and isopropanol, and tetrahydrofuran (THF).

4. The method of claim 1 , wherein the acid solution includes one or more of maleic acid, citric acid and succinic acid.

5. The method of claim 1 , wherein the base solution includes one or more of 4-methyl morpholine, morpholine, ammonium hydroxide and piperidine.

6. The method of claim 1 , wherein a computer program is used for determining relative proportions of acid solution, base solution, solvent and water.

7. The method of claim 1 , wherein the solvent includes one or more of acetone, acetonitrile, methanol, ethanol, n-propanol and isopropanol, and tetrahydrofuran (THF), wherein the acid solution includes one or more of maleic acid, citric acid and succinic acid, and wherein the base solution includes one or more of 4-methyl morpholine, morpholine, ammonium hydroxide and piperidine.

8. The method of claim 1 , wherein the gradient function comprises a fraction multiplier that provides predetermined changes in pH and/or solvent concentration, each being independent of the other, over a time period of interest.

9. The method according to claim 8 , wherein the fraction multiplier is selected from the group consisting of:

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Assignees

• Waters Technologies Corp

Inventors

• Wheat Thomas E
• Mcconville Patricia
• Lamoureux John R
• Chavali Aparna

Classifications

• G01N30/34 Primary

  of fluid composition, e.g. gradient (G01N30/36 takes precedence) · CPC title

• B01D15/168

  pH gradient or chromatofocusing, i.e. separation according to the isoelectric point pI · CPC title

• G01N2030/347

  mixers · CPC title

• G01N30/8658

  Optimising operation parameters · CPC title

• G01N2030/027

  Liquid chromatography · CPC title