Stabilized n,n-diethyl-p-phenylenediamine solution and method for detecting chlorine
A reagent for chlorine analysis includes N,N-diethyl-p-phenylenediamine (DPD), an inorganic chloride salt at a concentration of 0.5 M or more, and water. Additionally, a method for detecting chlorine in an aqueous sample includes subjecting a test sample to photometry. The test sample includes the aqueous sample; and a DPD reagent that includes DPD, an inorganic chloride salt at a concentration of 0.5 M or more, and water. The reagent and detection method can be used with minimal or no strong acids.
1 . A reagent for chlorine analysis, the reagent comprising:
N,N-diethyl-p-phenylenediamine (DPD);
an inorganic chloride salt at a concentration of 1.0 M or more; and
water.
2 . The reagent of claim 1 , wherein the reagent is stable for at least 30 days at 20° C.
3 . The reagent of claim 1 , further comprising one or more strong acids at a total concentration of 0.3 M or less.
4 . The reagent of claim 3 , wherein the total concentration of the one or more strong acids in the reagent is 0.2 M or less.
5 . The reagent of claim 3 , wherein the total concentration of the one or more strong acids in the reagent is 0.1 M or less.
6 . The reagent of claim 1 , not comprising any strong acids.
7 . The reagent of claim 1 , wherein the inorganic chloride salt is NaCl or KCl.
8 . The reagent of claim 1 , wherein the inorganic chloride salt is NaCl.
9 . The reagent of claim 1 , wherein the inorganic chloride salt is KCl.
10 . The reagent of claim 1 , wherein the concentration of the inorganic chloride salt in the reagent is 2.0 M or more.
11 . The reagent of claim 1 , wherein the concentration of the inorganic chloride salt in the reagent is 3.0 M or more.
12 . The reagent of claim 3 , wherein a molar ratio of the inorganic chloride salt to the one or more strong acids in the reagent is 30:1 or more.
13 . The reagent of claim 3 , wherein a molar ratio of the inorganic chloride salt to the one or more strong acids in the reagent is 50:1 or more.
14 . The reagent of claim 1 , wherein a concentration of the DPD in the reagent is 20 g/L or more.
15 . The reagent of claim 1 , wherein a molar ratio of the DPD to the inorganic chloride salt in the reagent is in a range of 1:5 to 1:40.
16 . The reagent of claim 3 , wherein a molar ratio of the DPD to the one or more strong acids in the reagent is in a range of 2:1 to 1:5.