Method, device and test reagent for detecting free available chlorine in aqueous fluids

• US 4,092,115 A
• Filed: 05/20/1977
• Issued: 05/30/1978
• Est. Priority Date: 04/11/1974
• Status: Expired due to Term

• Current Assignee: Environmental Test Systems, Inc. (Veralto Corp.)
• Original Assignee: Miles Laboratories, Inc. (Bayer AG)
• Inventors: Bauer, Robert, Rupe, Chauncey Orvis
• Primary Examiner(s): Reese, Robert M.
• Application Number:
  US05/798,750
• Time in Patent Office: 375 Days
• Field of Search: 23/230 R, 23/230 B, 23/253 TP, 195/103.5 R, 252/408, 116/114 AM
• US Class Current: 436/125
• CPC Class Codes: G01N 31/22 using chemical indicators G01N31/02 takes precedence
• CPC Class Codes: G01N 33/182 specific anions in water electrochemical analysis G01N27/26; detection of ions by colorimetry G01N31/22
• CPC Class Codes: Y10T 436/193333 In aqueous solution

Abstract

A method, device and test reagent for detecting free available chlorine in aqueous fluids which utilizes as an indicator substance azine compounds of the formula: ##STR1## where R and R'"'"' are hydroxy or amino substituents and X, X'"'"', Y and Y'"'"' are hydrogen, hydroxy, methyl or methoxy substituents and may be the same or different. Preferably such test reagents are incorporated with a carrier member or with a wicking device for concentrating the aqueous fluid being tested in the area of the test reagent.

Claims

1. A method for detecting only free available chlorine in an aqueous fluid suspected of containing both free and combined available chlorine which comprises contacting the fluid with a test reagent comprising an indicator substance selected from the group consisting of (1) a compound having the formula ##STR3## where R and R'"'"' are selected from the group consisting of hydroxy and amino groups and X, X'"'"', Y and Y'"'"' are selected from the group consisting of hydrogen, hydroxy, methyl and methoxy groups and (2) combinations thereof, and a buffer for adjusting the pH of the test reagent to about from 3.5 to 8.5;

and comparing the color obtained with colors obtained using standard chlorine containing aqueous fluids.

2. A method as in claim 1 wherein the pH of the test reagent is 6.0.

3. A method as in claim 1 wherein the indicator substance comprises syringaldazine.

4. A method as in claim 1 wherein the indicator substance is a combination of syringaldazine and vanillinazine.

5. A method as in claim 1 wherein the test reagent is incorporated with a carrier member.

6. A method as in claim 5 wherein the carrier member is bibulous paper and the test reagent is impregnated into or onto said paper.