Reaction mass of dipentene and (Z)-3,7-dimethylocta-1,3,6,-triene

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2019-10-09 to 2019-10-15

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Test Item Name: Ocimene PQ
- Laboratory Master Schedule No. at FumoPrep Ltd.: 4590
- Chemical Name: Reaction mass of (Z)-3,7-dimethylocta-1,3,6,-triene and dipentene
- Batch/Lot Number: A190618B
- CAS Number: 3338-55-4, 138-86-3
- Appearance: Colourless liquid
- Expiry Date: 30 June 2021
- Purity: 100%
- Storage Condition: Room temperature (15 – 25°C), protected from humidity (tight closed container) and under inert gas

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

A total of 10 tubes with Test Media (aqueous buffers at pH 4, 7 and 9) were spiked with the Spiking Stock Solution (test item at 4 mg/mL). Five of them were processed immediately to determine the initial concentration of the test item and the other five tubes were incubated at 50°C for 5 days and after the incubation period all the tubes were processed and measured.

Four control tubes were also prepared with Test Media (aqueous buffers at pH 4, 7 and 9) without spiking to check the potential interfering components from the buffer. Two of them were processed immediately to determine the initial concentration of the test item and the other two tubes were incubated at 50°C for 5 days and after the incubation period both control tubes were processed and measured.

Buffers:

Aqueous buffers at pH 4, 7 and 9 were used as Test Media.

Details on test conditions:

Aqueous buffer solutions of different pH values (pH 4, 7 and 9) were treated with the test substance or without (control) and incubated under controlled laboratory conditions. The Test Solutions were kept between 49.8 - 50.1°C. After 5 days, buffer solutions were analysed for the test substance and for hydrolysis.

Duration:

0 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

3.83 mg/L

Duration:

0 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

3.744 mg/L

Duration:

0 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

4.219 mg/L

Number of replicates:

Per each pH, two replicates for controls and five replicates for the test item solution were used.

Positive controls:

no

Negative controls:

yes

Remarks:

Test Media without spiking

Statistical methods:

To determine the test item concentration in the saturated solutions the following calculations were applied:

1. The corrected peak area and the relative peak area were calculated using the following equations:

Corrected Peak Area = Peak Area - Peak Area_Blank

Relative Peak Area = (Corrected Peak Area)/(Peak Area ISTD)

Where:
Corrected Peak Area is the corrected peak area (mVs)
Peak Area is the measured area value of the test item derivative from the individual injection (mVs)
Peak Area_Blank is the average area of the interfering compound from the corresponding Blank chromatograms (mVs)
Relative Peak Area is the relative peak area
Peak Area ISTD is the measured area value of the internal standard from the individual injection (mVs)

2. The average relative peak area from the parallel injections was calculated using the next formula:

Relative Peak Area_Average = Relative Peak Area_1+Relative Peak Area_2)/2

Where:
Relative Peak Area_Average is the average relative peak area of the individual injections
Relative Peak Area_1,2 are the relative peak area values of repeated injections

3. The concentration of the test solution was calculated using the following equation:

c_TestSol = (Relative Peak Area_Average - Intercept))/Slope ∙ AnDil./Enrich ∙ 1000

Where:
c_TestSol is the test item concentration in the test solution (mg/L)
Intercept is the intercept of the calibration curve
Slope is the slope of the calibration curve
AnDil. is the dilution of the analytical sample after the enrichment
Enrich is the enrichment during the sample preparation


The stability was determined:

Stability%= c_0/c_i ∙100%

Where:
c_0 and c_i are the test item concentrations measured on the initial and the end point of the experiment (mg/L)

Transformation products:

no

% Recovery:

39.4

pH:

4

Temp.:

50 °C

Duration:

120 h

% Recovery:

25

pH:

7

Temp.:

50 °C

Duration:

120 h

% Recovery:

22.1

pH:

9

Temp.:

50 °C

Duration:

120 h

Details on results:

Reported recovery (%) values correspond to Stability (%) values. Ocimene PQ exceeded 10% degradation when stored for 5 days at 50°C and at a pH 4, 7 and 9. Therefore, it is hydrolytically not stable.

Measured initial concentrations

Sample	cTheroretical(mg/L)	pH	cTestSol(mg/L)	cAverage(mg/L)	% of cTheor	RSD (%)
189-TS-428	0.000	4	<LOQ	<LOQ	N/A	N/A
189-TS-429	0.000	4	<LOQ
189-TS-430	4.010	4	3.932	3.830	95.5	7.3
189-TS-431	4.010	4	3.808
189-TS-432	4.010	4	3.373
189-TS-433	4.010	4	4.124
189-TS-434	4.010	4	3.912
189-TS-728	0.000	7	<LOQ	<LOQ	N/A	N/A
189-TS-729	0.000	7	<LOQ
189-TS-730	4.010	7	4.209	3.744	93.4	8.7
189-TS-731	4.010	7	3.503
189-TS-732	4.010	7	3.928
189-TS-733	4.010	7	3.404
189-TS-734	4.010	7	3.676
189-TS-928	0.000	9	<LOQ	<LOQ	N/A	N/A
189-TS-928	0.000	9	<LOQ
189-TS-930	4.010	9	4.590	4.219	105.2	6.6
189-TS-931	4.010	9	4.214
189-TS-932	4.010	9	4.202
189-TS-933	4.010	9	4.279
189-TS-934	4.010	9	3.809

 

 

Measured concentrations after 5 days

Sample	cTheroretical(mg/L)	pH	cTestSol(mg/L)	cAverage(mg/L)	% of cTheor	RSD (%)
189-TS-428	0.000	4	<LOQ	<LOQ	N/A	N/A
189-TS-429	0.000	4	<LOQ
189-TS-430	4.010	4	1.348	1.507	37.6	7.4
189-TS-431	4.010	4	1.592
189-TS-432	4.010	4	1.591
189-TS-433	4.010	4	1.431
189-TS-434	4.010	4	1.573
189-TS-728	0.000	7	<LOQ	<LOQ	N/A	N/A
189-TS-729	0.000	7	<LOQ
189-TS-730	4.010	7	1.215	0.938	23.4	42.0
189-TS-731	4.010	7	0.251
189-TS-732	4.010	7	1.175
189-TS-733	4.010	7	1.010
189-TS-734	4.010	7	1.039
189-TS-928	0.000	9	<LOQ	<LOQ	N/A	N/A
189-TS-928	0.000	9	<LOQ
189-TS-930	4.010	9	0.507	0.933	23.3	26.8
189-TS-931	4.010	9	1.048
189-TS-932	4.010	9	0.918
189-TS-933	4.010	9	1.058
189-TS-934	4.010	9	1.133

Stability of the test item after 5 days

pH	cTestSol(mg/L)		Stability (%)	Hydrolysis (%)
	Day-0	Day-5
4	3.830	1.507	39.4	60.6
7	3.744	0.938	25.0	75.0
9	4.219	0.933	22.1	77.9

 

Validity criteria fulfilled:

yes

Conclusions:

Ocimene PQ is hydrolytically not stable at 50 ºC.

Executive summary:

The potential for hydrolysis of Ocimene PQ was determined according to an OECD 111 guideline study. The Ocimene PQ exceeded 10% degradation when stored for 5 days at 50°C and at a pH 4, 7 and 9. Therefore, it is hydrolytically not stable at 50 ºC.

Description of key information

In a preliminary hydrolysis study the potential for hydrolysis of Ocimene PQ was determined according to an OECD 111 guideline study. The Ocimene PQ exceeded 10% degradation when stored for 5 days at 50°C and at a pH 4, 7 and 9. Therefore, it is hydrolytically not stable at 50 ºC.

In a second study the rate of degradation via hydrolysis of Ocimene PQ was determined the rate of degradation at pH 4, 7 and 9 and at 20, 35 and 50 °C. This was done in accordance with OECD TG 111. The hydrolysis Dissipation Time for 50% of the applied Ocimene PQ was determined to be 73.3 hours at a pH of 7 and temperature of 20 °C.

Key value for chemical safety assessment

Half-life for hydrolysis:

73.3 h

at the temperature of:

20 °C