Fractional determination of hydrogen peroxide and peracetic acid | Aut

HIRANUMA APPLICATION DATA

Automatic Titrator

Data No.

May. 10,2021

Organic acid

Fractional determination of hydrogen peroxide and peracetic acid

1. Abstract

Peracetic acid (CH₃COOOH) is used as oxidizing agent, bleaching agent, and fungicide. Peracetic acid generates acetic acid and oxygen by its decomposition. It is suggested that the bleaching and antiseptic properties are derived from this generated oxygen. On the other hand, hydrogen peroxide (H₂O₂) works as both oxidizing and reducing agents depending on the target chemical to be reacted. It is used as fungicide in food industry as well as peracetic acid.

Recently the usage of the mixed solution containing hydrogen peroxide, per acetic acid and acetic acid has been increasing for the sterilization of beverage containers along with the popularization of a plastic bottle as containers. This report introduces an example of fractional determination of hydrogen peroxide and peracetic acid in the mixed solution containing hydrogen peroxide, peracetic acid, and acetic acid.

The fractional titration of hydrogen peroxide and peracetic is performed as follows: first, hydrogen peroxide is titrated with potassium permanganate standard solution (formula(1)) after the sample solution is acidified with sulfuric acid. After the titration, add potassium iodide to generate iodine equivalent to peracetic acid (formula(2)). This generated iodine is titrated with sodium thiosulfate standard solution to determine the peracetic acid (formula(3)).

2MnO₄⁻ + 5H₂O₂ + 6H⁺ → 2Mn²⁺ + 5O₂(↑) + 8H₂O	・・・(1)
CH₃COOOH + 2I⁻ + 2H⁺ → I₂ + H₂O + CH₃COOH	・・・(2)
I₂ + 2Na₂S₂O₃ → 2NaI + Na₂S₄O₆	・・・(3)

2. Configuration of instruments and Reagents

(1)	Configuration
	Main unit	:	Automatic Titrator COM series
	Option	:	One buret
	Electrode	:	Platinum electrode　PT-301 Reference electrode　RE-201Z * PR-701BZ platinum reference electrode can also be used for measurement instead of above electrodes.
(2)	Reagents
	Titrant	:	0.02 mol/L Potassium permanganate standard solution 0.1 mol/L Sodium thiosulfate standard solution
	Additive	:	Diluted sulfuric acid (Sulfuric acid : DI water = 1 : 9 [v/v]) 1 mol/L Potassium iodide solution

3. Measurement procedure

(1)	Take 2 mL of sample into a 100 mL beaker with a volumetric pipette.
(2)	Add about 50 mL of DI water.
(3)	Add 2 mL of diluted sulfuric acid.
(4)	Immerse the electrodes to start titration. The titration with 0.02 mol/L potassium permanganate standard solution for hydrogen peroxide is performed.
(5)	After the titration of hydrogen peroxide is completed, the waiting time of 120 seconds is automatically counted according to the S-Timer setting. During this waiting time, add 2 mL of 1 mol/L potassium iodide solution using a micropipette.
(6)	After the S-Timer is finished, the titration with 0.1 mol/L sodium thiosulfate standard solution for peracetic acid are sequentially performed.

4. Measurement conditions and results

Examples of titration conditions

(1) Titration for hydrogen peroxide with potassium permanganate standard solution

Cndt No.	1
Method	Auto
Buret No.	1
Amp No.	2
D. Unit	mV
S-Timer	10	sec
C.P. mL	0	mL
T Timer	0	sec
D.P. mL	0.3	mL
End Sens	500
Over mL	0	mL
Max Vol.	20	mL

Constant No.	1
Size	2	mL
Blank	0	mL
Molarity	0.02	mol/L
Factor	1.003
K	85
L	0
Unit	%
Formula
	(D-B)KFM/(S10)
Decimal Places	3
Auto input Param.		None

Mode No.	5
Pre Int	0	sec
Del K	5
Del Sens	0	mV
Int Time	3	sec
Int Sens	3	mV
Brt Speed	2
Pulse	40

(2) Titration for peracetic acid with sodium thiosulfate standard solution

Cndt No.	3
Method	Auto
Buret No.	3
Amp No.	2
D. Unit	mV
S-Timer	120	sec
C.P. mL	0	mL
T Timer	0	sec
D.P. mL	0	mL
End Sens	300
Over mL	0.2	mL
Max Vol.	20	mL

Constant No.	3
Size	2	mL
Blank	0	mL
Molarity	0.1	mol/L
Factor	1.005
K	38.03
L	1
Unit	%
Formula
	(D-OAL)KFM/(S*10)	*1
Decimal Places	4
Auto input Param.		None

Mode No.	5
Pre Int	0	sec
Del K	5
Del Sens	0	mV
Int Time	3	sec
Int Sens	3	mV
Brt Speed	2
Pulse	40

*1”OA” and “L” in the formula

The excess potassium permanganate after the titration for hydrogen peroxide reacts with potassium iodide and generates iodine, therefore it must be subtracted. The “OA” in the formula means excess titrated volume of potassium permanganate, the concentration ratio of normality for potassium permanganate standard solution and sodium thiosulfate standard solution is entered to L (Coefficient 2). (“1” is entered on this report because normality of both reagents are 0.1 N.). The excess potassium permanganate is subtracted with this formula.

Measurement results

Measurement results of hydrogen peroxide

Meas. No.	Size (mL)	Titrant volume(mL)	Hydrogen peroxide Concentration (%)	Statistic calculation
1	2	13.219	1.127	Avg.	1.128 %
2	2	13.217	1.127	SD	0.0023 %
3	2	13.265	1.131	RSD	0.205 %

Examples of titration curves

Measurement results

Measurement results of peracetic acid

Meas. No.	Size (mL)	Titrant volume(mL)	Peracetic acid Concentration (%)	Statistic calculation
1	2	2.414	0.4363	Avg.	0.434 %
2	2	2.378	0.4290	SD	0.0041 %
3	2	2.416	0.4359	RSD	0.946 %

Examples of titration curves

5. Note

Hydrogen peroxide and peracetic acid were determined by redox titration. The addition of optional one buret allows to perform fractional titration for hydrogen peroxide and peracetic acid as described in this report. If required, add another optional buret for potassium iodide solution for more automation. However, the potassium iodide solution tends to precipitate, causing clogging of the flow path of buret. Therefore, it is necessary to remove the easily clogged buret tip from the buret for potassium iodide solution, and to clean the flow path with pure water after daily measurement.

Keywords： Hydrogen peroxide, Peracetic acid, Potassium permanganate, Potassium iodide, Sodium thiosulfate, Redox titration

*Some measurement would not be possible depending on optional configuration of system.

Tags: Hiranuma aquacounter autotitrator com-a19, Organic acid