1,8-bis(phenylthio)anthraquinone

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2015

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

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.2120 (Hydrolysis of Parent and Degradates as a Function of pH at 25°C)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.2130 (Hydrolysis as a Function of pH and Temperature)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Q30420AAYB

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: ambient (+5 to +30 °C), dark, dry

Radiolabelling:

no

Analytical monitoring:

not specified

Details on sampling:

At each sampling interval of each pH duplicate samples were removed from the test system. After the sampling the samples were stabilized 1/1 (v/v) with 100 % acetonitrile. Thereafter the samples were stored frozen before HPLC MS/MS analysis.

Buffers:

The test was carried out at three different pH values: pH 4, pH 7 and pH 9.
pH 4: 0.05 M citrate buffer (monopotassium citrate / sodium hydroxide)
pH 7: 0.05 M phosphate buffer (monopotassium phosphate / sodium hydroxide)
pH 9: 0.05 M borate buffer (H3BO3 in 0.01 M KCl/sodium hydroxide)
The pH of the buffer solutions used during the test was determined with a calibrated pH meter at the selected temperature with a precision of ± 0.1 pH units.

Details on test conditions:

The test was carried out using a thermostatically controlled water bath at ± 0.5 °C of the chosen temperature. The temperature was kept and measured to within ± 0.1 °C. Photolytic interference was avoided. All suitable precautions were taken to exclude dissolved oxygen (bubbling the buffer with argon for five minutes before preparing the test solution).

Duration:

120 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

0.04 mg/L

Duration:

120 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

0.038 mg/L

Duration:

120 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

0.042 mg/L

Number of replicates:

2 at each pH-value

Positive controls:

not specified

Negative controls:

not specified

Preliminary study:

The test item was found to be stable after incubation at 50 °C and at pH 4, pH 7 and pH 9 after 5 days (<10 % hydrolysis), hence, no further hydrolysis tests were necessary.

Transformation products:

not measured

% Recovery:

94.6

pH:

4

Temp.:

50 °C

Duration:

120 h

% Recovery:

90.9

pH:

7

Temp.:

50 °C

Duration:

120 h

% Recovery:

100.6

pH:

9

Temp.:

50 °C

Duration:

120 h

Key result

pH:

4

Temp.:

50 °C

Remarks on result:

hydrolytically stable based on preliminary test

Key result

pH:

7

Temp.:

50 °C

Remarks on result:

hydrolytically stable based on preliminary test

Key result

pH:

9

Temp.:

50 °C

Remarks on result:

hydrolytically stable based on preliminary test

Details on results:

No significant changes of the content in the samples were observed. At pH 4, 7 and 9 less than 10 % of the test item were hydrolysed within 120 hours at 50 °C.

Table1- Time course of FAT 36014/Z TE concentration at pH 4 at 50 °C

Time	Determined Content of FAT 93450/Z in Sample		Actual concentration
[h]	[mg/L]		in % of initial conc.
0	0.0418	100.0
120	0.0396	94.6

Table2:         Time course of FAT 93450/Z concentration at pH 7 at 50 °C

Time	Determined Content of FAT 93450/Z in Sample		Actual concentration
[h]	[mg/L]		in % of initial conc.
0	0.0421	100.0
120	0.0383	90.9

Table3:         Time course of FAT 93450/Z concentration at pH 9 at 50 °C

Time	Determined Content of FAT 93450/Z in Sample		Actual concentration
[h]	[mg/L]		in % of initial conc.
0	0.0414	100.0
120	0.0417	100.6

Validation of the Analytical Method

The method validation was performed with 0.05 M citrate buffer pH 4, 0.05 M phosphate buffer pH 7 and 0.05 M borate buffer pH 9. The accuracy and precision were considered acceptable since mean recoveries were in the range of 70 and 110 % with relative standard deviations below 20 %. The concentrations of the test item determined in blank samples were less than 30 % of the assigned LOQ of the test item. The LOD was set to 1/5 of the LOQ, while the signal to noise ratio was ≥3. The test item was quantified using the transition of m/z 425.0 to m/z 346.9. In addition, the test item was qualified by the transition m/z 425.0 to m/z 329.0.

Validity criteria fulfilled:

yes

Conclusions:

FAT 93450/Z was hydrolytically comparatively stable in buffered solutions under acidic (pH 4), neutral (pH 7) and alkaline (pH 9) conditions.

Executive summary:

The objective of the study was to determine the hydrolytic behavior of FAT 93450/Z at pH 4, 7 and 9 in aqueous solution at different temperatures according to OECD guideline 111. The study was performed with unlabelled FAT 93450/Z over a period of 120 hours (5 days) and a nominal test concentration of 0.05 mg/L. After application, the respective test solution was aliquoted into 20 test samples of 500 µL. Duplicate test systems were taken for analysis per sampling interval. The samples were stabilized with 500 µL acetonitrile to avoid further hydrolysis. FAT 93450/Z residues were analyzed by reversed phase HPLC-MS/MS in multiple reaction monitoringmode (MRM) using FAT 93450/Z TE standards in acetonitrile/water 1/1 (v/v). Sampling intervals for test 1 (preliminary test, 50 °C) were 0, 0.25, 1, 2, 3, 4 and 5 days of incubation. The method validation was performed with 0.05 M citrate buffer pH 4, 0.05 M phosphate buffer pH 7 and 0.05 M borate buffer pH 9. The accuracy and precision were considered acceptable since mean recoveries were in the range of 70 and 110 % with relative standard deviations below 20 %. After 120 hours incubation, the test item was found to be 94.6, 90.9 and 100.6 % of the intial concentration at pH 4, pH 7 and pH 9, respectively. Thus, the hydrolysis seen was <10 % of the initial concentration at pH 4, pH 7 and pH 9 in the preliminary study, hence the conduct of main study was considered not necessary. Based on these results, it was concluded that FAT 93450/Z was hydrolytically comparatively stable in buffered solutions under acidic (pH 4), neutral (pH 7) and alkaline (pH 9) conditions.

Description of key information

The hydrolytic behaviour of FAT 93450/Z at pH 4, 7 and 9 in aqueous solution was assessed over a period of 120 hours (5 days) and a nominal test concentration of 0.05 mg/L. After 120 hours incubation, the test item was found to be 94.6, 90.9 and 100.6 % of the intial concentration at pH 4, pH 7 and pH 9, respectively. Thus, the hydrolysis seen was <10 % of the initial concentration at pH 4, pH 7 and pH 9 in the preliminary study, hence the conduct of main study was considered not necessary. Based on these results, it was concluded that FAT 93450/Z was hydrolytically comparatively stable in buffered solutions under acidic (pH 4), neutral (pH 7) and alkaline (pH 9) conditions.

Key value for chemical safety assessment

Half-life for hydrolysis:

1 yr

at the temperature of:

50 °C