METHOD FOR DISTINGUISHING POTASSIUM CHLORATE FROM POTASSIUM BROMATE

Abstract

The present disclosure provides a method for distinguishing potassium chlorate from potassium bromate, including the following steps: using a “HCHO—NaHSO.sub.3—Na.sub.2SO.sub.3” pH clock system as a distinguishing solution, and distinguishing the potassium chlorate and the potassium bromate according to different responses, namely different induction times, of the pH clock system, caused by the potassium chlorate and the potassium bromate, respectively. In the present disclosure, the pH clock system provided by the distinguishing method has an intuitive graph, and can easily and quickly distinguish the potassium chlorate and the potassium bromate; meanwhile, the distinguishing method has simple equipment, a high accuracy, and easy operation and observation.

Claims

1. A method for distinguishing potassium chlorate from potassium bromate, comprising the following steps: preparing a sample potassium chlorate solution and a sample potassium bromate solution using distilled water as a solvent; and using a “HCHO—NaHSO.sub.3—Na.sub.2SO.sub.3” pH clock system as a distinguishing solution, and recording a graph of pH value changes with time; controlling the pH clock system at any specific temperature in a range of 20° C. to 25° C., and adding the sample potassium chlorate solution and the sample potassium bromate solution at a same concentration to two groups of the distinguishing solutions, respectively; and distinguishing the samples according to different induction times of the pH clock system caused by the samples: if the induction time of the pH clock is prolonged to a small extent after the sample solution is added, determining the sample as the potassium chlorate; if the induction time of the pH clock is prolonged to a large extent after the sample solution is added, determining the sample as the potassium bromate; wherein the distinguishing solution has 0.045 mol/L to 0.0625 mol/L of HCHO, 0.045 mol/L to 0.0625 mol/L of NaHSO.sub.3, and 0.0045 mol/L to 0.00625 mol/L of Na.sub.2SO.sub.3 by molar concentration.

2. The method according to claim 1, wherein the distinguishing solution has 0.051 mol/L of the HCHO, 0.0495 mol/L of the NaHSO.sub.3, and 0.00495 mol/L of the Na.sub.2SO.sub.3 by molar concentration.

3. The method according to claim 1, wherein the samples each have a distinguishable concentration range of 5.0×10.sup.−4 mol/L to 2.0×10.sup.−3 mol/L in the distinguishing solution.

4. The method according to claim 1, wherein the pH clock system is controlled at 25° C. when distinguishing the sample solution.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 shows a graph of changes of a pH value with time of a distinguishing solution (pH clock system) when a sample to be distinguished is not added in Example 1;

[0016] FIG. 2 shows a graph of changes of a pH value with time of the distinguishing solution (pH clock system) when 5×10.sup.4 mol/L KCIO.sub.3 is added in Example 1;

[0017] FIG. 3 shows a graph of changes of a pH value with time of the distinguishing solution (pH clock system) when 5×10.sup.4 mol/L KBrO.sub.3 is added in Example 1;

[0018] FIG. 4 shows a graph of changes of a pH value with time of the distinguishing solution (pH clock system) when the sample to be distinguished is not added in Example 2;

[0019] FIG. 5 shows a graph of changes of a pH value with time of the distinguishing solution (pH clock system) when 1×10.sup.−3 mol/L KCIO.sub.3 is added in Example 2;

[0020] FIG. 6 shows a graph of changes of a pH value with time of the distinguishing solution (pH clock system) when 1×10.sup.−3 mol/L KBrO.sub.3 is added in Example 2;

[0021] FIG. 7 shows a graph of changes of a pH value with time of the distinguishing solution (pH clock system) when the sample to be distinguished is not added in Example 3;

[0022] FIG. 8 shows a graph of changes of a pH value with time of the distinguishing solution (pH clock system) when 2×10.sup.−3 mol/L KCIO.sub.3 is added in Example 3; and

[0023] FIG. 9 shows a graph of changes of a pH value with time of the distinguishing solution (pH clock system) when 2×10.sup.−3 mol/L KBrO.sub.3 is added in Example 3.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Example 1

[0024] In this example, feasibility of a method for distinguishing potassium chlorate from potassium bromate of the present disclosure was verified as follows:

[0025] (1) Preparation of Sample Solutions

[0026] A mixed solution of 0.2 mol/L HCHO, 0.1 mol/L NaHSO.sub.3, and 0.01 mol/L Na.sub.2SO.sub.3 was prepared with distilled water. 10.0 mL of a distilled water solution, 19.8 mL of a NaHSO.sub.3—Na.sub.2SO.sub.3 mixed solution, and 10.2 mL of a 0.2 mol/L HCHO solution were added to a 50 mL small beaker in sequence, to ensure that a “HCHO—NaHSO.sub.3—Na.sub.2SO.sub.3” pH clock system had 0.051 mol/L of HCHO, 0.0495 mol/L of NaHSO.sub.3, and 0.00495 mol/L of Na.sub.2SO.sub.3, and had a total volume of 40 mL and a temperature controlled at 25° C.

[0027] 0.1 mol/L of a potassium chlorate solution and 0.1 mol/L of a potassium bromate solution were prepared with distilled water as a solvent.

[0028] (2) Obtaining a pH Clock Graph

[0029] A graph of pH value changes of the distinguishing solution over time was recorded by a computer equipped with a Chemical Signal Acquisition and Analysis program (no sample was added), as shown in FIG. 1. A pH induction time at 68 sec was used as a blank control. Another two groups of distinguishing solutions were prepared with the same concentration of each component as those in the above distinguishing solutions. For one group, 200 μL of a 0.1 mol/L potassium chlorate sample solution was added to 40 mL of the pH clock system at the same time as the reaction started, such that the concentration of potassium chlorate in the distinguishing solution was 5×10.sup.4 mol/L, the added potassium chlorate prolonged the induction time to 77 sec, as shown in FIG. 2. For the other group, 200 μL of a 0.1 mol/L potassium bromate sample solution was added to 40 mL of the pH clock system at the same time as the reaction started, such that the concentration of potassium bromate in the distinguishing solution was 5×10.sup.4 mol/L, the added potassium bromate prolonged the induction time to 85 sec, as shown in FIG. 3.

[0030] (3) Distinguishing

[0031] Potassium chlorate and potassium bromate have different influences on the induction time of the pH clock system due to their different chemical property. Comparing FIG. 2 and FIG. 3, it was seen that the potassium chlorate prolonged the induction time of the pH clock to a small extent; while the potassium bromate resulted in a considerable prolongation of the induction time of the pH clock. It was seen from the above experiments that the potassium chlorate can be distinguished from the potassium bromate by comparing the changes in the induction time of the pH clock system.

[0032] Two pre-prepared 0.1 mol/L solutions of the sample were taken (one was a potassium chlorate solution and the other was a potassium bromate solution, which were not distinguished), and one of them was marked as a sample 1 and the other was marked as a sample 2; and

[0033] two groups of pH clock system solutions with the same concentration of each component as above were prepared; 200 μL of the sample 1 at 0.1 mol/L and 200 μL of the sample 2 at 0.1 mol/L were added at the start of the pH clock, such that concentrations of the two samples in the distinguishing solution each were 5×10.sup.4 mol/L, and corresponding perturbed graph of a pH value with time were collected, respectively.

[0034] Analysis and comparison showed that: the sample 1 prolonged the induction time of the pH clock to a small extent (a pattern corresponded to FIG. 2, but did not correspond to FIG. 3); while the sample 2 prolonged the induction time of the pH clock to a large extent (a pattern corresponded to FIG. 3, but did not correspond to FIG. 2). Therefore, the sample 1 was a potassium chlorate solution, and the sample 2 was a potassium bromate solution, thereby distinguishing the potassium chlorate solution from the potassium bromate solution.

Example 2

[0035] In this example, feasibility of a method for distinguishing potassium chlorate from potassium bromate of the present disclosure was verified as follows:

[0036] (1) Preparation of Sample Solutions

[0037] A mixed solution of 0.2 mol/L HCHO, 0.1 mol/L NaHSO.sub.3, and 0.01 mol/L Na.sub.2SO.sub.3 was prepared with distilled water. 9.5 mL of a distilled water solution, 20.0 mL of a NaHSO.sub.3—Na.sub.2SO.sub.3 mixed solution, and 10.5 mL of a 0.2 mol/L HCHO solution were added to a 50 mL small beaker in sequence, to ensure that a “HCHO—NaHSO.sub.3—Na.sub.2SO.sub.3” pH clock system had 0.0525 mol/L of HCHO, 0.05 mol/L of NaHSO.sub.3, and 0.005 mol/L of Na.sub.2SO.sub.3, and had a total volume of 40 mL and a temperature controlled at 25° C.

[0038] 0.1 mol/L of a potassium chlorate solution and 0.1 mol/L of a potassium bromate solution were prepared with distilled water as a solvent.

[0039] (2) Obtaining a pH Clock Graph

[0040] A graph of pH value changes of the distinguishing solution over time was recorded by a computer equipped with a Chemical Signal Acquisition and Analysis program (no sample was added), as shown in FIG. 4. A pH induction time at 67 sec was used as a blank control. Another two groups of distinguishing solutions were prepared with the same concentration of each component as those in the above distinguishing solutions. For one group, 400 μL of a 0.1 mol/L potassium chlorate sample solution was added to 40 mL of the pH clock system at the same time as the reaction started, such that the concentration of potassium chlorate in the distinguishing solution was 1.0×10.sup.−3 mol/L, the added potassium chlorate prolonged the induction time to 81 sec, as shown in FIG. 5. For the other group, 400 μL of a 0.1 mol/L potassium bromate sample solution was added to 40 mL of the pH clock system at the same time as the reaction started, such that the concentration of potassium bromate in the distinguishing solution was 1.0×10.sup.−3 mol/L, the added potassium bromate prolonged the induction time to 88 sec, as shown in FIG. 6.

[0041] (3) Distinguishing

[0042] Potassium chlorate and potassium bromate have different influences on the induction time of the pH clock system due to their different chemical property. Comparing FIG. 5 and FIG. 6, it was seen that the potassium chlorate prolonged the induction time of the pH clock to a small extent; while the potassium bromate resulted in a considerable prolongation of the induction time of the pH clock. It was seen from the above experiments that the potassium chlorate can be distinguished from the potassium bromate by comparing the changes in the induction time of the pH clock system.

[0043] Two pre-prepared 0.1 mol/L solutions of the sample were taken (one was a potassium chlorate solution and the other was a potassium bromate solution, which were not distinguished), and one of them was marked as a sample 1 and the other was marked as a sample 2; and

[0044] two groups of pH clock system solutions with the same concentration of each component as above were prepared; 400 μL of the sample 1 at 0.1 mol/L and 400 μL of the sample 2 at 0.1 mol/L were added at the start of the pH clock, such that concentrations of the two samples in the distinguishing solution each were 1×10.sup.−3 mol/L, and corresponding perturbed graph of a pH value with time were collected, respectively.

[0045] Analysis and comparison showed that: the sample 1 prolonged the induction time of the pH clock to a small extent (a pattern corresponded to FIG. 5, but did not correspond to FIG. 6); while the sample 2 prolonged the induction time of the pH clock to a large extent (a pattern corresponded to FIG. 6, but did not correspond to FIG. 5). Therefore, the sample 1 was a potassium chlorate solution, and the sample 2 was a potassium bromate solution, thereby distinguishing the potassium chlorate solution from the potassium bromate solution.

Example 3

[0046] In this example, feasibility of a method for distinguishing potassium chlorate from potassium bromate of the present disclosure was verified as follows:

[0047] (1) Preparation of Sample Solutions

[0048] A mixed solution of 0.2 mol/L HCHO, 0.1 mol/L NaHSO.sub.3, and 0.01 mol/L Na.sub.2SO.sub.3 was prepared with distilled water. 10.2 mL of a distilled water solution, 20 mL of a NaHSO.sub.3—Na.sub.2SO.sub.3 mixed solution, and 9.8 mL of a 0.2 mol/L HCHO solution were added to a 50 mL small beaker in sequence, to ensure that a “HCHO—NaHSO.sub.3—Na.sub.2SO.sub.3” pH clock system had 0.049 mol/L of HCHO, 0.05 mol/L of NaHSO.sub.3, and 0.005 mol/L of Na.sub.2SO.sub.3, and had a total volume of 40 mL and a temperature controlled at 25° C.

[0049] 0.1 mol/L of a potassium chlorate solution and 0.1 mol/L of a potassium bromate solution were prepared with distilled water as a solvent.

[0050] (2) Obtaining a pH Clock Graph

[0051] A graph of pH value changes of the distinguishing solution over time was recorded by a computer equipped with a Chemical Signal Acquisition and Analysis program (no sample was added), as shown in FIG. 7. A pH induction time at 68 sec was used as a blank control. Another two groups of distinguishing solutions were prepared with the same concentration of each component as those in the above distinguishing solutions. For one group, 800 μL of a 0.1 mol/L potassium chlorate sample solution was added to 40 mL of the pH clock system at the same time as the reaction started, such that the concentration of potassium chlorate in the distinguishing solution was 2.0×10.sup.−3 mol/L, the added potassium chlorate prolonged the induction time to 102 sec, as shown in FIG. 8. For the other group, 800 μL of a 0.1 mol/L potassium bromate sample solution was added to 40 mL of the pH clock system at the same time as the reaction started, such that the concentration of potassium bromate in the distinguishing solution was 2.0×10.sup.−3 mol/L, the added potassium bromate prolonged the induction time to 123 sec, as shown in FIG. 9.

[0052] (3) Distinguishing

[0053] Potassium chlorate and potassium bromate have different influences on the induction time of the pH clock system due to their different chemical property. Comparing FIG. 8 and FIG. 9, it was seen that the potassium chlorate prolonged the induction time of the pH clock to a small extent; while the potassium bromate resulted in a considerable prolongation of the induction time of the pH clock. It was seen from the above experiments that the potassium chlorate can be distinguished from the potassium bromate by comparing the changes in the induction time of the pH clock system.

[0054] Two pre-prepared 0.1 mol/L solutions of the sample were taken (one was a potassium chlorate solution and the other was a potassium bromate solution, which were not distinguished), and one of them was marked as a sample 1 and the other was marked as a sample 2; and

[0055] two groups of pH clock system solutions with the same concentration of each component as above were prepared; 800 μL of the sample 1 at 0.1 mol/L and 800 μL of the sample 2 at 0.1 mol/L were added at the start of the pH clock, such that concentrations of the two samples in the distinguishing solution each were 2×10.sup.−3 mol/L, and corresponding perturbed graph of a pH value with time were collected, respectively.

[0056] Analysis and comparison showed that: the sample 1 prolonged the induction time of the pH clock to a small extent (a pattern corresponded to FIG. 8, but did not correspond to FIG. 9); while the sample 2 prolonged the induction time of the pH clock to a large extent (a pattern corresponded to FIG. 9, but did not correspond to FIG. 8). Therefore, the sample 1 was a potassium chlorate solution, and the sample 2 was a potassium bromate solution, thereby distinguishing the potassium chlorate solution from the potassium bromate solution.

[0057] It can be seen from the above examples that the potassium chlorate solution and the potassium bromate solution with a smaller or greater concentration can also be distinguished by the method of the present disclosure.