Zinc Chelate Complex

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

September 2020 - January 2021

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)

Deviations:

no

Principles of method if other than guideline:

Since the test item was expected to hydrolyze rather fast, the conditions of the preliminary test were modified from the conditions given in the guideline. The test was carried out at 20 °C ± 0.5 °C. Samples were taken at the start and after 10 minutes and 30 minutes.

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Storage conditions: Controlled room temperature (15-25°C, ≤70% relative humidity), protected from light and humidity (stored in a tightly closed container)

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

Since the test item itself cannot be determined by a suitable analytical method, the samples were analysed for the tentantive hydrolysis product LZ 399. The analysis of LZ 399 was carried out by GC/FID detection - using matrix matched standards - after saturation of the samples with an excess of sodium chloride and extraction with ethylacetate.

Buffers:

- pH 4: Mixture of 360 mL of 0.1 M sodium hydroxide, 2000 mL of 0.1 M potassium citrate and 1640 mL of water. Measured pH value: 4.01
- pH 7: Mixture of 1184 mL of 0.1 M sodium hydroxide, 2000 mL of 0.1 M potassium dihydrogenphosphate and 816 mL of water. Measured pH value: 7.03
- pH 9: Mixture of 852 mL of 0.1 M sodium hydroxide, 2000 mL of boric acid and 1148 mL of water. Measured pH value: 8.99

Details on test conditions:

Since the test item was expected to hydrolyze rather fast, the conditions of the preliminary test were modified from the conditions given in the guideline. The test was carried out at 20 °C ± 0.5 °C. Samples of the test item in buffer solution pH 4, pH 7 and pH 9 were prepared and incubated for 30 minutes. Samples were taken immediately after preparation, after 10 minutes and 30 minutes.

Duration:

30 min

pH:

4

Temp.:

20 °C

Initial conc. measured:

ca. 19 mg/L

Duration:

30 min

pH:

7

Temp.:

20 °C

Initial conc. measured:

ca. 19 mg/L

Duration:

30 min

pH:

9

Temp.:

30 °C

Initial conc. measured:

ca. 19 mg/L

Number of replicates:

test was carried out in duplicate

Positive controls:

no

Negative controls:

no

Statistical methods:

no statistics

Preliminary study:

The test item is not stable in aqueous buffer pH 4, 7 and 9 and immediately hydrolyses completely into LZ 399. Thus, the half-life time for hydolytical degradation is < 1 minute for buffer solutions at pH 4, 7 and 9.

Test performance:

The test was carried out at 20 °C ± 0.5 °C. Samples of the test item in buffer solution pH 4, pH 7 and pH 9 were prepared and incubated for 30 minutes. Samples were taken immediately after preparation, after 10 minutes and 30 minutes.

Transformation products:

yes

No.:

#1

Details on hydrolysis and appearance of transformation product(s):

The test item is not stable in aqueous buffer pH 4, 7 and 9 and immediately hydrolyses completely into LZ 399. Thus, the half-life time for hydolytical degradation is < 1 minute for buffer solutions at pH 4, 7 and 9.

% Recovery:

0

pH:

4

Temp.:

20 °C

Duration:

30 min

Remarks on result:

other: t1/2 = < 1 minute

% Recovery:

0

pH:

7

Temp.:

20 °C

Duration:

30 min

Remarks on result:

other: t1/2 = < 1 minute

% Recovery:

0

pH:

9

Temp.:

20 °C

Duration:

30 min

Remarks on result:

other: t1/2 = < 1 minute

Key result

pH:

4

Temp.:

20 °C

DT50:

< 1 min

Remarks on result:

other: hydrolytically unstable

Key result

pH:

7

Temp.:

20 °C

DT50:

< 1 min

Remarks on result:

other: hydrolytically unstable

Key result

pH:

9

Temp.:

20 °C

DT50:

< 1 min

Remarks on result:

other: hydrolytically unstable

Details on results:

The test item is not stable in aqueous buffer pH 4, 7 and 9 and immediately hydrolyses completely into LZ 399. Thus, the half-life time for hydolytical degradation is < 1 minute for buffer solutions at pH 4, 7 and 9.

Results with reference substance:

no reference substance tested

Validity criteria fulfilled:

yes

Conclusions:

The test item is not stable in aqueous buffer pH 4, 7 and 9 and immediately hydrolyses completely into LZ 399. Thus, the half-life time for hydrolytical degradation is < 1 minute for buffer solutions at pH 4, 7 and 9. Therefore, no main study had to be performed.

Executive summary:

In this study the hydrolysis was determined based on the OECD Guideline no. 111. Since the test item was expected to hydrolyze rather fast, a preliminary test with conditions modified from the conditions given in the guideline, was carried out. The test was carried out at 20 °C ± 0.5 °C. Samples of the test item in buffer solution pH 4, pH 7 and pH 9 were prepared and incubated for 30 minutes. Samples were taken immediately after preparation, after 10 minutes and 30 minutes. Since the test item itself cannot be determined by a suitable analytical method, the samples were analysed for the tentantive hydrolysis product LZ 399. The analysis of LZ 399 was carried out by GC/FID detection - using matrix matched standards - after saturation of the samples with an excess of sodium chloride and extraction with ethylacetate.

The test item is not stable in aqueous buffer pH 4, 7 and 9 and immediately hydrolyses completely into LZ 399. Thus, the half-life time for hydrolytical degradation is < 1 minute for buffer solutions at pH 4, 7 and 9. Therefore, no main study had to be performed.

Description of key information

In this study the hydrolysis was determined based on the OECD Guideline no. 111. Since the test item was expected to hydrolyze rather fast, a preliminary test with conditions modified from the conditions given in the guideline, was carried out. The test was carried out at 20 °C ± 0.5 °C. Samples of the test item in buffer solution pH 4, pH 7 and pH 9 were prepared and incubated for 30 minutes. Samples were taken immediately after preparation, after 10 minutes and 30 minutes. Since the test item itself cannot be determined by a suitable analytical method, the samples were analysed for the tentantive hydrolysis product LZ 399. The analysis of LZ 399 was carried out by GC/FID detection - using matrix matched standards - after saturation of the samples with an excess of sodium chloride and extraction with ethylacetate.

The test item is not stable in aqueous buffer pH 4, 7 and 9 and immediately hydrolyses completely into LZ 399. Thus, the half-life time for hydrolytical degradation is < 1 minute for buffer solutions at pH 4, 7 and 9. Therefore, no main study had to be performed.

Key value for chemical safety assessment

Half-life for hydrolysis:

1 min

at the temperature of:

20 °C