Titration control method

• US 4,302,299 A
• Filed: 10/04/1979
• Issued: 11/24/1981
• Est. Priority Date: 12/27/1977
• Status: Expired due to Term

• Current Assignee: Mitsubishi Kasei Corp. (Mitsubishi Chemical Group Corp.)
• Original Assignee: Mitsubishi Kasei Kogyo Kabushiki Kaisha
• Inventors: Ishikawa, Seiji
• Primary Examiner(s): Kaplan, G. L.
• Application Number:
  US06/082,227
• Time in Patent Office: 782 Days
• Field of Search: 204/195 T, 204/1 T, 204/1 M, 364/497, 364/500, 364/579, 23/230 R
• US Class Current: 205/787.5
• CPC Class Codes: G01N 27/44 using electrolysis to generate a reagent, e.g. for titration
• CPC Class Codes: G01N 31/164 by electrical or electrochemical means
• CPC Class Codes: Y10T 436/116664 with automated titrator

Abstract

In a titration controlling method and apparatus wherein variations of a titration system caused by intermittent titrations are successively detected electrically, and the quantity of each intermittent titration is controlled by an electric signal obtained by the detection until an end point is reached. According to the present invention, the quantity of each intermittent titration is determined by dividing the quantity of the immediately prior titration, which has been memorized, by the variation of the titration system caused by the immediately prior titration.

Claims

1. In a titration control method comprising the steps of successively detecting an electric potential representing a concentration of a subject material to be titrated, and controlling a quantity of each intermittent titration based on an electric signal obtained from detected values of a potential until an end point is reached, the improvement wherein said control of the quantity of each intermittent titration is carried out in accordance with a following equation:

##EQU4## wherein Q_n ;

quantity of n-th intermittent titration, n being an integer larger than 0,

Q_n-1 ;

quantity of (n-1)th intermittent titration,

K;

a constant,

X_o ;

a value of said electric potential detected just before the (n-1)th intermittent titration Q_n-1,

X_l ;

a value of said electric potential detected just after the (n-1)th intermittent titration Q_n-1.

2. A titration controlling method as set forth in claim 1 further comprising the steps of comparing the quantity of each intermittent titration with the quantity of an immediately prior titration, thereby finding out an inflection point where the quantity of the titration exceeds the quantity of the immediately prior titration, and utilizing the inflection point as the end point of the titration.

3. A titration controlling method as set forth in claim 1 further comprising the steps of successively comparing each electric potential detected in the titration with a preset value, and determining an instant where the electric potential is equal to the preset value as an end point of the titration.

4. A titration control method as set forth in claim 1 wherein said electrical potential represents a pH value.