Formaldehyde, oligomeric reaction products with acetone and diphenylamine

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11 July 2016 to 09 December 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)

Deviations:

no

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

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

Preliminary test - Tier 1 – Acquisition m/z 170 -> m/z 93
The buffer solutions were filter-sterilised through a 0.2 µm FP 30/0.2 CA-S filter (Whatman, Dassel, Germany) and transferred into a sterile vessel. To exclude oxygen, nitrogen gas was purged through the solution for 5 minutes. The test item was spiked to the solutions at a target concentration of 130 µg/L using a spiking solution in tetrahydrofuran. For each sampling time, duplicate sterile vessels under vacuum were filled with 6 mL test solution and placed in the dark in a temperature controlled environment at 50.1°C +/- 0.1°C.
Note: the spiking volume was < 1% of the sample volume. Nominal concentrations were not corrected for the spiking volume.
The concentration of the test item in the test samples was determined immediately after preparation (t=0) and after 6 days. The samples taken at t=6 days were cooled to room temperature using running tap water. The samples were diluted in a 1:1 (v:v) ratio with acetonitrile and analysed.
Blank buffer solutions containing a similar content of blank spiking solution were treated similarly as the test samples and analysed at t=0.
The pH of each of the test solutions (except for the blanks) was determined at each sampling time.

Preliminary test - Tier 1 – Acquisition m/z 391.2 -> m/z 182
The buffer solutions were filter-sterilised through a 0.2 µm FP 30/0.2 CA-S filter (Whatman, Dassel, Germany) and transferred into a sterile vessel. To exclude oxygen, nitrogen gas was purged through the solution for 5 minutes. The test item was spiked to the solutions at a target concentration of 24 µg/L using a spiking solution in tetrahydrofuran. For each sampling time, duplicate sterile vessels under vacuum were filled with 6 mL test solution and placed in the dark in a temperature controlled environment at 50.1°C +/- 0.1°C.
Note: the spiking volume was < 1% of the sample volume. Nominal concentrations were not corrected for the spiking volume.
The concentration of the test item in the test samples was determined immediately after preparation (t=0) and after 6 days. The samples taken at t=6 days were cooled to room temperature using running tap water. The samples were diluted in a 1:1 (v:v) ratio with acetonitrile and analysed.
Blank buffer solutions containing a similar content of blank spiking solution were treated similarly as the test samples and analysed at t=0.
The pH of each of the test solutions (except for the blanks) was determined at each sampling time.

Main study - Tier 2 – Acquisition m/z 170 -> m/z 93
Test samples were prepared and treated similarly as during the preliminary test.
The concentrations of the test item were determined immediately after preparation (t=0) and at several sampling points after t=0.
The samples not analysed on the sampling day were stored in the freezer. Storage stability under these conditions was determined by the analysis of additional accuracy samples prepared at the nominal concentration of the test samples.
On the day of analysis, the frozen samples were defrosted at room temperature, treated and analysed. The stored samples were found to be stable if the mean accuracy was in the range 70-110%. This applied for accuracy samples in buffer pH 7 and pH 9. The mean accuracy of accuracy samples in pH 4 was 114%. As the specification was only slightly exceeded, the result was accepted. Based on this samples in all buffers were considered stable when stored in the freezer for 14 days (detailed results are archived in the raw data).
Blank buffer solutions were treated similarly as the test samples and analysed at t=0.
The pH of each of the test solutions (except for the blanks) was determined at least at the beginning and at the end of the test.

Main study - Tier 2 – Acquisition m/z 391.2 -> m/z 182
Test samples were prepared and treated similarly as during the preliminary test.
The concentrations of the test item were determined immediately after preparation (t=0) and at several sampling points after t=0.
Blank buffer solutions were treated similarly as the test samples and analysed at t=0.
The pH of each of the test solutions (except for the blanks) was determined at least at the beginning and at the end of the test.

Buffers:

Acetate buffer pH 4, 0.01 M: A solution of 16.7% 0.01 M sodium acetate in water and 83.3% 0.01 M acetic acid in water. The buffer contained 0.0009% (w/v) sodium azide.
Phosphate buffer pH 7, 0.01 M: A solution of 0.01 M potassium di-hydrogenphosphate in water adjusted to pH 7 using 1 N sodium hydroxide. The buffer contained 0.0009% (w/v) sodium azide.
Borate buffer pH 9, 0.01 M: A solution of 0.01 M boric acid in water and 0.01 M potassium chloride in water adjusted to pH 9 using 1 N sodium hydroxide. The buffer contained 0.0009% (w/v) sodium azide.

Details on test conditions:

Main study - Tier 2 – Acquisition m/z 170 -> m/z 93
The study was performed at the following temperatures:
pH code Temperature I Temperature II Temperature III
pH 4 19.9°C +/- 0.3°C 50.2°C +/- 0.2°C 60.2°C +/- 0.2°C
pH 7 19.9°C +/- 0.3°C 50.2°C +/- 0.2°C 60.2°C +/- 0.2°C
pH 9 19.9°C +/- 0.3°C 50.2°C +/- 0.2°C 60.0°C +/- 0.1°C

Main study - Tier 2 – Acquisition m/z 391.2 -> m/z 182
The study was performed at the following temperatures:
pH code Temperature I Temperature II Temperature III
pH 4 19.9°C +/- 0.2°C 40.1°C +/- 0.1°C 50.2°C +/- 0.1°C
pH 7 19.9°C +/- 0.2°C 40.2°C +/- 0.1°C 50.3°C +/- 0.2°C
pH 9 19.9°C +/- 0.2°C 40.2°C +/- 0.2°C 50.3°C +/- 0.1°C

Identification of hydrolysis products – Tier 3
Research to investigate the identity or nature and rates of formation and decline of hydrolysis products was not required since the studies were conducted according to the testing guidelines provided in Annex VIII (volume 10-100 tons/year).

Duration:

794.85 h

pH:

4

Temp.:

20 °C

Initial conc. measured:

144.5 µg/L

Remarks:

Acquisition m/z 170 -> m/z 93

Duration:

723.05 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

173 µg/L

Remarks:

Acquisition m/z 170 -> m/z 93

Duration:

74.53 h

pH:

4

Temp.:

60 °C

Initial conc. measured:

132.5 µg/L

Remarks:

Acquisition m/z 170 -> m/z 93

Duration:

794.6 h

pH:

7

Temp.:

20 °C

Initial conc. measured:

141 µg/L

Remarks:

Acquisition m/z 170 -> m/z 93

Duration:

723.75 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

149.5 µg/L

Remarks:

Acquisition m/z 170 -> m/z 93

Duration:

73.8 h

pH:

7

Temp.:

60 °C

Initial conc. measured:

144.5 µg/L

Remarks:

Acquisition m/z 170 -> m/z 93

Duration:

794.38 h

pH:

9

Temp.:

20 °C

Initial conc. measured:

138 µg/L

Remarks:

Acquisition m/z 170 -> m/z 93

Duration:

723.03 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

160 µg/L

Remarks:

Acquisition m/z 170 -> m/z 93

Duration:

73.8 h

pH:

9

Temp.:

60 °C

Initial conc. measured:

136.5 µg/L

Remarks:

Acquisition m/z 170 -> m/z 93

Duration:

120.8 h

pH:

4

Temp.:

20 °C

Initial conc. measured:

16.1 µg/L

Remarks:

Acquisition m/z 391.2 -> m/z 182

Duration:

146.47 h

pH:

4

Temp.:

40 °C

Initial conc. measured:

9.8 µg/L

Remarks:

Acquisition m/z 391.2 -> m/z 182

Duration:

22.42 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

16.6 µg/L

Remarks:

Acquisition m/z 391.2 -> m/z 182

Duration:

163.98 h

pH:

7

Temp.:

20 °C

Initial conc. measured:

13.7 µg/L

Remarks:

Acquisition m/z 391.2 -> m/z 182

Duration:

116.3 h

pH:

7

Temp.:

40 °C

Initial conc. measured:

11.1 µg/L

Remarks:

Acquisition m/z 391.2 -> m/z 182

Duration:

23.68 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

17.65 µg/L

Remarks:

Acquisition m/z 391.2 -> m/z 182

Duration:

96.72 h

pH:

9

Temp.:

20 °C

Initial conc. measured:

21.05 µg/L

Remarks:

Acquisition m/z 391.2 -> m/z 182

Duration:

97.08 h

pH:

9

Temp.:

40 °C

Initial conc. measured:

20.1 µg/L

Remarks:

Acquisition m/z 391.2 -> m/z 182

Duration:

48.52 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

20.8 µg/L

Remarks:

Acquisition m/z 391.2 -> m/z 182

Number of replicates:

Two

Positive controls:

no

Negative controls:

yes

Remarks:

Blank buffer solution

Preliminary study:

Preliminary test - Tier 1 – Acquisition m/z 170 -> m/z 93
A degree of hydrolysis of ≥ 10% was observed at pH 4, pH 7 and pH 9 after 6 days. According to the guideline, the higher Tier test was required if the preliminary test demonstrated ≥ 10% hydrolysis within 5 days. As the obtained degrees of hydrolysis significantly exceeded 10%, the hydrolysis time of 6 days rather than 5 days did not alter the conclusion of the preliminary test.
In the blank buffer solutions no test item was detected.

Preliminary test - Tier 1 – Acquisition m/z 391.2 -> m/z 182
A degree of hydrolysis of ≥ 10% was observed at pH 4, pH 7 and pH 9 after 6 days. According to the guideline, the higher Tier test was required if the preliminary test demonstrated ≥ 10% hydrolysis within 5 days. As the obtained degrees of hydrolysis significantly exceeded 10%, the hydrolysis time of 6 days rather than 5 days did not alter the conclusion of the preliminary test.
A small response was observed in the blank pH 4 and pH 7 buffer solution. This was probably caused by carry-over since a similar response was observed in the analytical blank. The presence of this signal did not hamper accurate evaluation of the results of the preliminary test.
In the blank pH 4 and pH 9 buffer solutions no test item was detected.

Test performance:

Preliminary test - Tier 1 – Acquisition m/z 170 -> m/z 93
The mean recoveries of the of the test item containing buffer solutions at t=0 fell within the criterion range of 90-110%. It demonstrated that the analytical method was adequate to support the hydrolysis study on the test item.

Preliminary test - Tier 1 – Acquisition m/z 391.2 -> m/z 182
The mean recovery of the test-item containing buffer pH 7 solutions at t=0 fell within the criterion range of 90-110%. The mean recoveries of the test-item containing buffer pH 4 solutions at t=0 fell within the acceptable range of 70-110% for non-labelled chemicals. It demonstrated that the analytical method was adequate to support the hydrolysis study on the test item. The mean recovery of test-item containing buffer pH 9 solutions at t=0 was 115%. This was considered acceptable, as the criterion range of 90-110% was only slightly exceeded.

Transformation products:

not measured

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

Not measured.

Key result

pH:

4

Temp.:

20 °C

DT50:

234 h

Type:

other: This is the disappearance time 50 (DT50) calculated by non-linear regression.

Remarks on result:

other: Acquisition m/z 170 -> m/z 93

Key result

pH:

4

Temp.:

50 °C

DT50:

28 h

Type:

other: This is the disappearance time 50 (DT50) calculated by non-linear regression.

Remarks on result:

other: Acquisition m/z 170 -> m/z 93

Key result

pH:

4

Temp.:

60 °C

DT50:

2.2 h

Type:

other: This is the disappearance time 50 (DT50) calculated by non-linear regression.

Remarks on result:

other: Acquisition m/z 170 -> m/z 93

Key result

pH:

7

Temp.:

20 °C

DT50:

467 h

Type:

other: This is the disappearance time 50 (DT50) calculated by non-linear regression.

Remarks on result:

other: Acquisition m/z 170 -> m/z 93

Key result

pH:

7

Temp.:

50 °C

DT50:

26 h

Type:

other: This is the disappearance time 50 (DT50) calculated by non-linear regression.

Remarks on result:

other: Acquisition m/z 170 -> m/z 93

Key result

pH:

7

Temp.:

60 °C

DT50:

1.9 h

Type:

other: This is the disappearance time 50 (DT50) calculated by non-linear regression.

Remarks on result:

other: Acquisition m/z 170 -> m/z 93

Key result

pH:

9

Temp.:

20 °C

DT50:

532 h

Type:

other: This is the disappearance time 50 (DT50) calculated by non-linear regression.

Remarks on result:

other: Acquisition m/z 170 -> m/z 93

Key result

pH:

9

Temp.:

50 °C

DT50:

17.9 h

Type:

other: This is the disappearance time 50 (DT50) calculated by non-linear regression.

Remarks on result:

other: Acquisition m/z 170 -> m/z 93

Key result

pH:

9

Temp.:

60 °C

DT50:

2.3 h

Type:

other: This is the disappearance time 50 (DT50) calculated by non-linear regression.

Remarks on result:

other: Acquisition m/z 170 -> m/z 93

Key result

pH:

4

Temp.:

20 °C

DT50:

2.9 h

Type:

other: This is the disappearance time 50 (DT50) calculated by non-linear regression.

Remarks on result:

other: Acquisition m/z 391.2 -> m/z 182

Key result

pH:

4

Temp.:

40 °C

DT50:

0.2 h

Type:

other: This is the disappearance time 50 (DT50) calculated by non-linear regression.

Remarks on result:

other: Acquisition m/z 391.2 -> m/z 182

Key result

pH:

4

Temp.:

50 °C

DT50:

0.27 h

Type:

other: This is the disappearance time 50 (DT50) calculated by non-linear regression.

Remarks on result:

other: Acquisition m/z 391.2 -> m/z 182

Key result

pH:

7

Temp.:

20 °C

DT50:

4.3 h

Type:

other: This is the disappearance time 50 (DT50) calculated by non-linear regression.

Remarks on result:

other: Acquisition m/z 391.2 -> m/z 182

Key result

pH:

7

Temp.:

40 °C

DT50:

0.77 h

Type:

other: This is the disappearance time 50 (DT50) calculated by non-linear regression.

Remarks on result:

other: Acquisition m/z 391.2 -> m/z 182

Key result

pH:

7

Temp.:

50 °C

DT50:

0.32 h

Type:

other: This is the disappearance time 50 (DT50) calculated by non-linear regression.

Remarks on result:

other: Acquisition m/z 391.2 -> m/z 182

Other kinetic parameters:

See table above for DT50 values. At all temperatures, non-linear relationships were observed. Accordingly the model for pseudo-first order reactions was not applicable and half-life times of the test item could not be calculated.

Details on results:

Main study - Tier 2 – Acquisition m/z 170 -> m/z 93
pH 4
No test item was detected in the blank buffer solutions.
The mean recovery of the test item containing buffer solution for the test at 60°C at t=0 fell within the criterion range of 90-110%. It demonstrated that the analytical method was adequate to support the hydrolysis study on the test item.
The mean recovery of the test item containing buffer solution for the tests at 20 and 40°C at t=0 exceeded the criterion range of 90-110%, as it was 111% and 133% respectively. The mean recovery was considered acceptable, as the criterion of 90 – 110% was only slightly exceeded. The influence of a possible overestimation observing 133% was evaluated during data processing.
For testing of pseudo-first order kinetics the mean logarithms of the relative concentrations between 10% and 90% were plotted against time. Especially at 50°C and at 60°C, non-linear relationships were observed. Accordingly the model for pseudo-first order reactions was not applicable and half-life times of the test item could not be calculated. Instead, values for the disappearance time 50 (DT50) were calculated by non-linear regression with the Software program Prism version 4.03 (Graphpad Software, San Diego, USA).

pH 7
No test item was detected in the blank buffer solutions.
The mean recoveries of the test item containing buffer solutions at t=0 were 109, 115 and 111% for the studies at 20, 50 and 60°C. The recovery of the study at 20°C fell within the criterion range of 90-110%. It demonstrated that the analytical method was adequate to support the hydrolysis study on the test item. The recovery of the studies at 50 and 60°C were accepted as the criterion range of 90-110% was only slightly exceeded.
For testing of pseudo-first order kinetics the mean logarithms of the relative concentrations between 10% and 90% were plotted against time. At all temperatures, non-linear relationships were observed. Accordingly the model for pseudo-first order reactions was not applicable and half-life times of the test item could not be calculated. Instead, values for the DT50 were calculated by non-linear regression with the Software program Prism version 4.03.

pH 9
No test item was detected in the blank buffer solutions.
The mean recoveries of the test item containing buffer solutions at t=0 fell within the criterion range of 90-110%. It demonstrated that the analytical method was adequate to support the hydrolysis study on the test item. The mean recovery of the test item containing buffer solution for the tests at 50°C at t=0 exceeded the criterion range of 90-110%, as it was 123%. The mean recovery was considered acceptable, as the criterion of 90 – 110% was only slightly exceeded.
For testing of pseudo-first order kinetics the mean logarithms of the relative concentrations between 10% and 90% were plotted against time. Especially at 60°C, a non-linear relationship was observed. Accordingly the model for pseudo-first order reactions was not applicable and half-life times of the test item could not be calculated. Instead, values for the DT50 were calculated by non-linear regression with the Software program Prism version 4.03.

Main study - Tier 2 – Acquisition m/z 391.2 -> m/z 182
During Tier 2 testing and acquiring date for m/z 391.2 -> m/z 182, several mean recoveries of the test item containing buffer solutions at t=0 fell below the criterion range of 90-110% and even 70-110%. Re-preparing of the test solutions paying special attention to swift sample treatment did not improve recovery significantly. Results are archived in the raw data. The too-low recoveries were considered to derive from very quick degradation of the monitored component. Accordingly, achieved recoveries reflect what was technically possible.

pH 4
In the blank buffer solutions small responses were detected at the retention time of the test item. This was probably caused by carry-over since a higher response was found in the corresponding blanks. Therefore, observed signals did not impact the study.
The mean recoveries of the test item containing buffer solutions at t=0 fell below the criterion range of 70-110%.
For testing of pseudo-first order kinetics the mean logarithms of the relative concentrations between 10% and 90% were plotted against time. At all temperatures, non-linear relationships were observed. Accordingly the model for pseudo-first order reactions was not applicable and half-life times of the test item could not be calculated. Instead, values for the DT50 were calculated by non-linear regression with the Software program Prism version 4.03.

pH 7
In the blank buffer solutions small responses were detected at the retention time of the test item. This was probably caused by carry-over since a higher response was found in the corresponding blanks. Therefore, observed signals did not impact the study.
The mean recoveries of the test item containing buffer solutions at t=0 from the study at 20°C and at 40°C fell below the criterion range of 70-110%. The mean recoveries of the test-item containing buffer solutions at t=0 from the study at 50°C fell within the acceptable range of 70-110% for non-labelled chemicals.
For testing of pseudo-first order kinetics the mean logarithms of the relative concentrations between 10% and 90% were plotted against time. At all temperatures, non-linear relationships were observed. Accordingly the model for pseudo-first order reactions was not applicable and half-life times of the test item could not be calculated. Instead, values for the DT50 were calculated by non-linear regression with the Software program Prism version 4.03.

pH 9
In the blank buffer solutions small responses were detected at the retention time of the test item. This was probably caused by carry-over since a higher response was found in the corresponding blanks. Therefore, observed signals did not impact the study.
The mean recoveries of the test item containing buffer solutions at t=0 fell within the acceptable range for non labelled chemicals of 70-110%. It demonstrated that the analytical method was adequate to support the hydrolysis study on the test item.
For testing of pseudo-first order kinetics the mean logarithms of the relative concentrations between 10% and 90% were plotted against time. At all temperatures, non-linear relationships were observed. Accordingly the model for pseudo-first order reactions was not applicable and half-life times of the test item could not be calculated. Instead, values for the DT50 were calculated by non-linear regression with the Software program Prism version 4.03

Main test – hydrolysis of the test item at pH 4 and 20°C – Acquisition m/z 170 -> m/z 93

Sampling time [hours]	Analysed concentration [µg/L]	Relative concentration [%]	Logarithm relative concentration	Actual pH
0	144	100	2.00	4.0
0	145	100	2.00	4.0
69.93	129	89	1.95	4.1
69.93	130	90	1.95	4.0
123.12	104	72	1.86	4.1
123.12	103	71	1.85	4.1
218.67	90.8	63	1.80	4.1
218.67	93.7	65	1.81	4.1
313.05	76.6	53	1.72	4.1
313.05	75.9	52	1.72	4.1
385.22	88.2	61	1.79	4.1
385.22	87.3	60	1.78	4.1
458.85	84.5	58	1.77	4.1
458.85	84.8	59	1.77	4.1
577.18	81.0	56	1.75	4.1
577.18	66.8	46	1.66	4.1
646.47	66.6	46	1.66	4.1
646.47	56.6	39	1.59	4.1
794.85	64.7	45	1.65	4.1
794.85	65.5	45	1.66	4.1

Main test – hydrolysis of the test item at pH 4 and 50°C – Acquisition m/z 170 -> m/z 93

Sampling time [hours]	Analysed concentration [µg/L]	Relative concentration [%]	Logarithm relative concentration	Actual pH
0.00	173	100	2.00	4.0
0.00	173	100	2.00	4.0
2.90	141	81	1.91	4.0
2.90	140	81	1.91	4.1
24.52	95.7	55	1.74	4.1
24.52	96.1	56	1.74	4.1
25.53	93.5	54	1.73	4.0
25.53	97.1	56	1.75	4.0
26.50	95.7	55	1.74	4.1
26.50	96.2	56	1.74	4.1
27.52	93.3	54	1.73	4.1
27.52	95.3	55	1.74	4.1
28.58	95.1	55	1.74	4.1
28.58	93.1	54	1.73	4.1
73.10	48.7	28	1.45	4.1
73.10	48.4	28	1.45	4.1
146.98	38.2	22	1.34	4.1
146.98	35.2	20	1.31	4.1
192.87	32.6	19	1.27	4.1
192.87	32.5	19	1.27	4.1
241.40	23.1	13	1.12	4.2
241.40	22.8	13	1.12	4.2
313.57	29.2	17	1.23	4.1
313.57	26.2	15	1.18	4.1
387.25	19.5	11	1.05	4.1
387.25	20.6	12	1.08	4.1
574.83	12.9	7.5	0.87	4.1
574.83	12.1	7.0	0.85	4.1
723.05	n.d.	n.a.	n.a.	4.2
723.05	n.d.	n.a.	n.a.	4.2

Main test – hydrolysis of the test item at pH 4 and 60°C – Acquisition m/z 170 -> m/z 93

Sampling time [hours]	Analysed concentration [µg/L]	Relative concentration [%]	Logarithm relative concentration	Actual pH
0.00	131	99	1.99	4.0
0.00	134	101	2.01	4.0
3.28	60.5	46	1.66	4.0
3.28	59.0	45	1.65	4.0
21.80	23.7	18	1.25	4.1
21.80	24.2	18	1.26	4.1
24.78	22.1	17	1.22	4.1
24.78	24.5	18	1.27	4.1
25.07	26.2	20	1.30	4.1
25.07	26.1	20	1.29	4.1
26.18	26.5	20	1.30	4.1
26.18	26.1	20	1.30	4.1
26.45	26.1	20	1.29	4.1
26.45	26.5	20	1.30	4.1
47.35	17.2	13	1.11	4.1
47.35	17.9	14	1.13	4.1
74.53	12.0	9.1	0.96	4.1
74.53	12.4	9.4	0.97	4.1

Recoveries during the main study at pH 4 – Acquisition m/z 170 -> m/z 93

Temperature (°C)	Nominal concentration [µg/L]	Analysed concentration [µg/L]	Recovery [%]	Mean recovery [%]
20	130	144	111	111
	130	145	112
50	130	173	133	133
	130	173	133
60	130	131	101	102
	130	134	103

Disappearance time 50 at pH 4 – Acquisition m/z 170 -> m/z 93

Temperature [°C]	DT50 [hours]	95% Confidence Intervals [hours]
20	234	120 to 349
50^1	28	25 to 31
60	2.2	1.8 to 2.6

¹In order to evaluate the influence of a possible overestimation at t=0, modelling was repeated assuming the nominal concentration as the analytical result at t=0. This shifted the DT50 to a somewhat higher value: 66.73 hours with a confidence interval of 53.82 to 79.65 hours.

Main test – hydrolysis of the test item at pH 7 and 20°C – Acquisition m/z 170 -> m/z 93

Sampling time [hours]	Analysed concentration [µg/L]	Relative concentration [%]	Logarithm relative concentration	Actual pH
0.00	144	102	2.01	7.0
0.00	138	98	1.99	7.0
69.68	119	84	1.93	7.0
69.68	121	85	1.93	7.0
122.87	109	77	1.89	7.0
122.87	109	77	1.89	7.0
312.80	77.4	55	1.74	7.0
312.80	78.1	55	1.74	7.0
384.97	89.7	63	1.80	7.0
384.97	89.0	63	1.80	7.0
458.60	79.5	56	1.75	7.0
458.60	79.6	56	1.75	7.0
576.93	74.9	53	1.72	7.0
576.93	75.5	53	1.73	7.0
646.22	31.5	22	1.35	7.0
646.22	29.2	21	1.32	7.0
794.60	61.2	43	1.64	7.0
794.60	61.1	43	1.64	7.0

Main test – hydrolysis of the test item at pH 7 and 50°C – Acquisition m/z 170 -> m/z 93

Sampling time [hours]	Analysed concentration [µg/L]	Relative concentration [%]	Logarithm relative concentration	Actual pH
0.00	150	100	2.00	7.0
0.00	149	100	2.00	7.0
3.60	118	79	1.90	7.0
3.60	119	80	1.90	7.0
25.22	84.8	57	1.75	7.0
25.22	83.8	56	1.75	7.0
26.23	83.2	56	1.75	6.9
26.23	84.1	56	1.75	7.0
27.20	81.8	55	1.74	7.0
27.20	82.9	55	1.74	7.0
28.22	84.6	57	1.75	7.0
28.22	81.7	55	1.74	7.0
29.28	80.2	54	1.73	7.0
29.28	84.3	56	1.75	7.0
73.80	48.5	32	1.51	7.0
73.80	47.7	32	1.50	7.0
193.57	34.3	23	1.36	7.0
193.57	35.7	24	1.38	7.0
242.10	25.3	17	1.23	6.9
242.10	25.0	17	1.22	7.0
314.27	27.2	18	1.26	7.0
314.27	28.5	19	1.28	7.0
387.95	21.2	14	1.15	7.0
387.95	20.8	14	1.14	7.0
723.75	n.d.	n.a.	n.a.	7.0
723.75	n.d.	n.a.	n.a.	7.0

Main test – hydrolysis of the test item at pH 7 and 60°C – Acquisition m/z 170 -> m/z 93

Sampling time [hours]	Analysed concentration [µg/L]	Relative concentration [%]	Logarithm relative concentration	Actual pH
0.00	144	100	2.00	7.0
0.00	145	100	2.00	7.0
2.55	67.9	47	1.67	7.0
2.55	68.2	47	1.67	7.0
21.07	26.1	18	1.26	7.0
21.07	26.3	18	1.26	7.0
24.05	26.9	19	1.27	7.0
24.05	23.7	16	1.21	7.0
24.33	24.1	17	1.22	7.0
24.33	24.2	17	1.22	7.0
25.45	25.2	17	1.24	7.0
25.45	26.3	18	1.26	7.0
25.72	25.5	18	1.25	7.0
25.72	25.1	17	1.24	7.0
46.62	16.8	12	1.07	7.0
46.62	16.9	12	1.07	7.0
73.80	12.1	8.4	0.92	7.0
73.80	13.0	9.0	0.96	7.0

Recoveries during the main study at pH 7 – Acquisition m/z 170 -> m/z 93

Temperature (°C)	Nominal concentration [µg/L]	Analysed concentration [µg/L]	Recovery [%]	Mean recovery [%]
20	130	144	111	109
	130	138	106
50	130	150	115	115
	130	149	115
60	130	144	111	111
	130	145	111

Disappearance time 50 at pH 7 – Acquisition m/z 170 -> m/z 93

Temperature [°C]	DT50 [hours]	95% Confidence Intervals [hours]
20	467	-37 to 971
50	26	23 to 30
60	1.9	1.6 to 2.1

Main test – hydrolysis of the test item at pH 9 and 20°C

Sampling time [hours]	Analysed concentration [µg/L]	Relative concentration [%]	Logarithm relative concentration	Actual pH
0.00	135	98	1.99	9.0
0.00	141	102	2.01	9.0
69.47	116	84	1.93	9.0
69.47	117	85	1.93	9.0
122.65	104^1	75	1.88	9.0
122.65	104^1	75	1.88	9.0
218.20	93	68	1.83	9.0
218.20	86	63	1.80	9.0
312.58	77	56	1.75	9.0
312.58	76	55	1.74	9.0
384.75	70	51	1.71	9.0
384.75	71	52	1.71	9.0
458.38	59	43	1.63	9.0
458.38	59	43	1.63	9.0
576.72	30	22	1.34	9.0
576.72	35	25	1.41	9.0
646.00	29	21	1.32	9.0
646.00	23	17	1.23	9.0
794.38	51	37	1.57	9.0
794.38	50	36	1.56	9.0

¹Estimated value, calculated by extrapolation of the calibration curve.

Main test – hydrolysis of the test item at pH 9 and 50°C

Sampling time [hours]	Analysed concentration [µg/L]	Relative concentration [%]	Logarithm relative concentration	Actual pH
0.00	160	100	2.00	8.9
0.00	160	100	2.00	8.9
2.88	127	80	1.90	9.0
2.88	129	81	1.91	8.9
24.50	74.9	47	1.67	8.9
24.50	76.0	48	1.68	8.9
25.52	78.0	49	1.69	8.9
25.52	75.4	47	1.67	8.9
26.48	72.6	45	1.66	8.9
26.48	73.9	46	1.67	8.9
27.50	68.8	43	1.63	8.9
27.50	68.5	43	1.63	8.9
28.57	68.6	43	1.63	9.0
28.57	68.3	43	1.63	9.0
73.08	45.2	28	1.45	8.9
73.08	44.8	28	1.45	8.9
146.97	35.8	22	1.35	8.9
146.97	34.8	22	1.34	8.9
241.38	23.8	15	1.17	8.9
241.38	25.7	16	1.21	8.9
313.55	24.1	15	1.18	8.9
313.55	23.3	15	1.16	8.9
387.23	18.4	12	1.06	8.9
387.23	17.7	11	1.05	8.9
574.82	7.99	5.0	0.70	8.9
574.82	5.68	3.6	0.55	8.9
723.03	n.d.	n.a.	n.a.	8.9
723.03	n.d.	n.a.	n.a.	8.9

Main test – hydrolysis of the test item at pH 9 and 60°C

Sampling time [hours]	Analysed concentration [µg/L]	Relative concentration [%]	Logarithm relative concentration	Actual pH
0	135	99	2.00	8.9
0	138	101	2.00	8.9
2.55	69.1	51	1.70	8.9
2.55	70.1	51	1.71	8.9
21.07	25.1	18	1.26	8.9
21.07	26.0	19	1.28	8.9
24.05	23.3	17	1.23	8.9
24.05	23.1	17	1.23	8.9
24.33	24.2	18	1.25	9.0
24.33	24.2	18	1.25	8.9
25.45	25.7	19	1.27	8.9
25.45	23.3	17	1.23	8.9
25.72	22.8	17	1.22	8.9
25.72	24.5	18	1.25	9.0
46.62	14.5	11	1.03	8.9
46.62	14.3	10	1.02	8.9
73.80	12.3	9.0	0.95	8.9
73.80	12.0	8.8	0.94	8.9

Recoveries

Temperature (°C)	Nominal concentration [µg/L]	Analysed concentration [µg/L]	Recovery [%]	Mean recovery [%]
20	130	135	104	106
	130	141	108
50	130	160	123	123
	130	160	123
60	130	135	104	105
	130	138	106

Disappearance time 50 at pH 9 – Acquisition m/z 170 -> m/z 93

Temperature [°C]	DT50 [hours]	95% Confidence Intervals [hours]
20	532	193 to 872
50	17.9	15.6 to 20.2
60	2.3	2.0 to 2.6

Main test – hydrolysis of the test item at pH 4 and 20°C – Acquisition m/z 391.2 -> m/z 182

Sampling time [hours]	Analysed concentration [µg/L]	Relative concentration [%]	Logarithm relative concentration	Actual pH
0.00	15.9	99	1.99	4.0
0.00	16.3	101	2.01	4.0
1.05	12.1	75	1.87	4.0
1.05	12.5	77	1.89	4.0
2.05	9.78	61	1.78	4.0
2.05	9.25	57	1.76	4.0
2.53	11.4	71	1.85	4.0
2.53	9.06	56	1.75	4.0
3.02	10.2	64	1.80	4.0
3.02	9.61	60	1.78	4.0
3.53	5.48	34	1.53	4.0
3.53	5.59	35	1.54	4.0
4.05	5.21	32	1.51	4.1
4.05	6.57	41	1.61	4.0
48.65	1.92	12	1.08	4.1
48.65	1.39	8.6	0.94	4.0
120.8	1.42	8.8	0.94	4.0
120.8	1.11	6.9	0.84	4.0

Main test – hydrolysis of the test item at pH 4 and 40°C – Acquisition m/z 391.2 -> m/z 182

Sampling time [hours]	Analysed concentration [µg/L]	Relative concentration [%]	Logarithm relative concentration	Actual pH
0.00	10.0	102	2.01	4.0
0.00	9.60	98	1.99	4.0
0.45	3.80	39	1.59	4.0
0.45	4.64	47	1.68	4.0
1.32	2.68	27	1.44	4.0
1.32	2.34	24	1.38	4.0
1.85	3.32	34	1.53	4.0
1.85	2.46	25	1.40	4.0
2.32	2.32	24	1.38	4.0
2.32	2.52	26	1.41	4.0
2.63	1.96	20	1.30	4.0
2.63	3.71	38	1.58	4.0
2.97	3.92	40	1.60	4.0
2.97	2.41	25	1.39	4.0
72.13	2.35	24	1.38	4.0
72.13	2.53	26	1.41	4.0
146.47	0.45^1	4.6	0.66	4.1
146.47	1.04	11	1.03	4.0

¹Estimated value, calculated by extrapolation of the calibration curve.

Main test – hydrolysis of the test item at pH 4 and 50°C – Acquisition m/z 391.2 -> m/z 182

Sampling time [hours]	Analysed concentration [µg/L]	Relative concentration [%]	Logarithm relative concentration	Actual pH
0.00	17.2	104	2.02	4.0
0.00	15.9	96	1.98	4.0
0.25	10.3	62	1.79	4.0
0.25	8.04	49	1.69	4.0
0.48	6.46	39	1.59	4.0
0.48	6.69	40	1.61	4.0
0.72	5.35	32	1.51	4.0
0.72	4.36	26	1.42	4.0
0.98	3.24	20	1.29	4.0
0.98	3.75	23	1.35	4.0
1.20	3.07	19	1.27	4.0
1.20	3.74	23	1.35	4.0
1.52	3.48	21	1.32	4.0
1.52	3.20	19	1.29	4.0
2.53	2.11	13	1.11	4.0
2.53	2.23	13	1.13	4.0
22.42	1.07	6.5	0.81	4.0
22.42	0.96^1	5.8	0.76	4.0

¹Estimated value, calculated by extrapolation of the calibration curve.

Recoveries during the main study at pH 4 – Acquisition m/z 391.2 -> m/z 182

Temperature (°C)	Nominal concentration [µg/L]	Analysed concentration [µg/L]	Recovery [%]	Mean recovery [%]
20	24.0	15.9	66	67
	24.0	16.3	68
40	24.0	10.0	42	41
	24.0	9.60	40
50	24.0	17.2	72	69
	24.0	15.9	66

Disappearance time 50 at pH 4 – Acquisition m/z 391.2 -> m/z 182

Temperature [°C]	DT50 [hours]	95% Confidence Intervals [hours]
20	2.9	2.0 to 3.7
40	0.20	0.06 to 0.35
50	0.27	0.22 to 0.32

Main test – hydrolysis of the test item at pH 7 and 20°C – Acquisition m/z 391.2 -> m/z 182

Sampling time [hours]	Analysed concentration [µg/L]	Relative concentration [%]	Logarithm relative concentration	Actual pH
0.00	14.7	108	2.03	7.0
0.00	12.6	92	1.96	7.0
0.17	11.3	83	1.92	7.0
0.17	11.3	83	1.92	7.0
0.43	11.0	81	1.91	7.0
0.43	13.3	97	1.99	7.0
0.68	18.6	136	2.13	7.0
0.68	10.6	77	1.89	7.0
0.97	12.7	93	1.97	7.0
0.97	11.3	83	1.92	7.0
1.53	10.1	74	1.87	7.0
1.53	10.6	78	1.89	7.0
1.82	8.94	65	1.82	7.0
1.82	7.86	58	1.76	7.0
47.87	2.26	17	1.22	7.0
47.87	2.62	19	1.28	7.0
71.42	1.86	14	1.13	7.0
71.42	1.80	13	1.12	7.0
144.37	2.38	17	1.24	7.0
144.37	1.78	13	1.12	7.0
163.98	0.86^1	6.3	0.80	7.0
163.98	1.04	7.6	0.88	7.0

¹Estimated value, calculated by extrapolation of the calibration curve.

Main test – hydrolysis of the test item at pH 7 and 40°C – Acquisition m/z 391.2 -> m/z 182

Sampling time [hours]	Analysed concentration [µg/L]	Relative concentration [%]	Logarithm relative concentration	Actual pH
0.00	11.0	99	1.99	7.0
0.00	11.2	101	2.01	7.0
0.27	7.58	68	1.83	7.0
0.27	9.02	81	1.91	7.0
0.55	5.92	53	1.73	7.0
0.55	9.44	85	1.93	7.0
0.85	5.77	52	1.72	7.0
0.85	5.34	48	1.68	7.0
1.20	3.69	33	1.52	7.0
1.20	3.43	31	1.49	7.0
1.87	4.80	43	1.64	7.0
1.87	5.46	49	1.69	7.0
2.20	3.74	34	1.53	7.0
2.20	0.11^1	1.0	0.01	7.0
23.70	1.51	14	1.13	7.0
23.70	1.12	10	1.00	7.0
96.68	1.02	9.2	0.96	7.0
96.68	1.39	13	1.10	7.0
116.30	0.79^1	7.1	0.85	7.0
116.30	0.85^1	7.7	0.88	7.0

¹Estimated value, calculated by extrapolation of the calibration curve.

Main test – hydrolysis of the test item at pH 7 and 50°C – Acquisition m/z 391.2 -> m/z 182

Sampling time [hours]	Analysed concentration [µg/L]	Relative concentration [%]	Logarithm relative concentration	Actual pH
0.00	16.7	95	1.98	7.0
0.00	18.6	105	2.02	7.0
0.25	9.28	53	1.72	7.0
0.25	8.87	50	1.70	7.0
0.53	7.15	41	1.61	7.0
0.53	8.35	47	1.68	7.0
0.83	4.62	26	1.42	7.0
0.83	5.10	29	1.46	7.0
1.18	4.89	28	1.44	7.0
1.18	4.19	24	1.38	7.0
1.85	2.72	15	1.19	7.0
1.85	1.56	8.9	0.95	7.0
2.18	1.21	6.9	0.84	7.0
2.18	1.38	7.8	0.89	7.0
23.68	0.65^1	3.7	0.57	7.0
23.68	0.55^1	3.1	0.49	7.0

¹Estimated value, calculated by extrapolation of the calibration curve.

Recoveries during the main study at pH 7 – Acquisition m/z 391.2 -> m/z 182

Temperature (°C)	Nominal concentration [µg/L]	Analysed concentration [µg/L]	Recovery [%]	Mean recovery [%]
20	24.0	14.7	61	57
	24.0	12.6	52
40	24.0	11.0	46	46
	24.0	11.2	47
50	24.0	16.7	70	73
	24.0	18.6	77

Disappearance time 50 at pH 7 – Acquisition m/z 391.2 -> m/z 182

Temperature [°C]	DT50 [hours]	95% Confidence Intervals [hours]
20	4.3	1.4 to 7.1
40	0.77	0.51 to 1.02
50	0.32	0.23 to 0.41

Main test – hydrolysis of the test item at pH 9 and 20°C – Acquisition m/z 391.2 -> m/z 182

Sampling time [hours]	Analysed concentration [µg/L]	Relative concentration [%]	Logarithm relative concentration	Actual pH
0.00	21.6	103	2.01	8.9
0.00	20.5	97	1.99	8.9
0.97	18.0	86	1.93	8.9
0.97	18.1	86	1.93	8.9
1.98	15.2	72	1.86	9.0
1.98	15.3	73	1.86	8.9
2.97	14.2	67	1.83	8.9
2.97	13.0	62	1.79	9.0
3.55	13.9	66	1.82	9.0
3.55	13.3	63	1.80	8.9
4.05	12.3	59	1.77	8.9
4.05	12.1	58	1.76	8.9
4.58	14.4	68	1.83	9.0
4.58	11.6	55	1.74	9.0
48.53	3.66	17	1.24	8.9
48.53	3.73	18	1.25	8.9
75.48	2.71	13	1.11	8.9
75.48	3.12	15	1.17	8.9
96.72	2.09	10	1.00	8.9
96.72	1.93	9.2	0.96	8.9

Main test – hydrolysis of the test item at pH 9 and 40°C – Acquisition m/z 391.2 -> m/z 182

Sampling time [hours]	Analysed concentration [µg/L]	Relative concentration [%]	Logarithm relative concentration	Actual pH
0.00	19.3	96	1.98	9.0
0.00	20.9	104	2.02	8.9
0.70	13.3	66	1.82	8.9
0.70	13.0	65	1.81	8.9
1.13	12.2	61	1.78	8.9
1.13	12.5	62	1.79	8.9
1.90	8.92	44	1.65	8.9
1.90	10.2	51	1.70	9.0
2.23	9.65	48	1.68	8.9
2.23	10.9	54	1.73	9.0
2.78	9.88	49	1.69	8.9
2.78	9.91	49	1.69	9.0
3.23	7.47	37	1.57	8.9
3.23	10.0	50	1.70	8.9
48.48	2.79	14	1.14	8.9
48.48	2.15	11	1.03	8.9
75.63	2.43	12	1.08	8.9
75.63	3.16	16	1.20	8.9
97.08	1.71	8.5	0.93	8.9
97.08	2.01	10	1.00	8.9

Main test – hydrolysis of the test item at pH 9 and 50°C – Acquisition m/z 391.2 -> m/z 182

Sampling time [hours]	Analysed concentration [µg/L]	Relative concentration [%]	Logarithm relative concentration	Actual pH
0.00	20.4	98	1.99	8.9
0.00	21.2	102	2.01	8.9
0.25	13.5	65	1.81	8.9
0.25	13.4	65	1.81	8.9
0.50	11.5	55	1.74	8.9
0.50	11.6	56	1.75	8.9
0.77	9.47	46	1.66	8.9
0.77	10.2	49	1.69	8.9
1.03	8.03	39	1.59	9.0
1.03	8.12	39	1.59	8.9
1.62	5.67	27	1.44	8.9
1.62	6.18	30	1.47	8.9
1.92	4.94	24	1.38	8.9
1.92	5.14	25	1.39	9.0
48.52	0.72^1	3.5	0.54	8.9
48.52	0.92^1	4.4	0.65	8.9

¹Estimated value, calculated by extrapolation of the calibration curve.

Recoveries during the main study at pH 9 – Acquisition m/z 391.2 -> m/z 182

Temperature (°C)	Nominal concentration [µg/L]	Analysed concentration [µg/L]	Recovery [%]	Mean recovery [%]
20	24.0	21.6	90	88
	24.0	20.5	85
40	24.0	19.3	80	84
	24.0	20.9	87
50	24.0	20.4	85	87
	24.0	21.2	88

Disappearance time 50 at pH 9 – Acquisition m/z 391.2 -> m/z 182

Temperature [°C]	DT50 [hours]	95% Confidence Intervals [hours]
20	5.4	4.7 to 6.1
40	1.6	1.3 to 1.9
50	0.56	0.48 to 0.63

Validity criteria fulfilled:

yes

Conclusions:

The preliminary test (Tier 1) and main study (Tier 2) were performed for the determination of the rate of hydrolysis of Formaldehyde, oligomeric reaction products with acetone and diphenylamine at pH values normally found in the environment (pH 4-9). Hydrolysis behaviour was investigated for the m/z associated with diphenylamine and for an m/z of a higher-molecular-weight reaction product.
Acquiring m/z 170 -> m/z 93 the DT50 of the test item were:
DT50 (95% Confidence Intervals) [hours]
Temperature
[°C] pH 4 pH 7 pH 9
20 234 (120 to 349) 467 (-37 to 971) 532 (193 to 872)
50 28 (25 to 31) 26 (23 to 30) 17.9 (15.6 to 20.2)
60 2.2 (1.8 to 2.6) 1.9 (1.6 to 2.1) 2.3 (2.0 to 2.6)

Acquiring m/z 391.2 -> m/z 182 the DT50 of the test item were:
DT50 (95% Confidence Intervals) [hours]
Temperature
[°C] pH 4 pH 7 pH 9
20 2.9 (2.0 to 3.7) 4.3 (1.4 to 7.1) 5.4 (4.7 to 6.1)
40 0.20 (0.06 to 0.35) 0.77 (0.51 to 1.02) 1.6 (1.3 to 1.9)
50 0.27 (0.22 to 0.32) 0.32 (0.23 to 0.41) 0.56 (0.48 to 0.63)

Executive summary:

In accordance with OECD Guideline 111, the preliminary test (Tier 1) and main study (Tier 2) were performed for the determination of the rate of hydrolysis of Formaldehyde, oligomeric reaction products with acetone and diphenylamine at pH values normally found in the environment (pH 4-9). Hydrolysis behaviour was investigated for the m/z associated with diphenylamine and for an m/z of a higher-molecular-weight reaction product.

Acquiring m/z 170 -> m/z 93 the DT50 of the test item were:

	DT50 (95% Confidence Intervals) [hours]
Temperature [°C]	pH 4	pH 7	pH 9
20	234 (120 to 349)	467 (-37 to 971)	532 (193 to 872)
50	28 (25 to 31)	26 (23 to 30)	17.9 (15.6 to 20.2)
60	2.2 (1.8 to 2.6)	1.9 (1.6 to 2.1)	2.3 (2.0 to 2.6)

 

Acquiring m/z 391.2 -> m/z 182 the DT50 of the test item were:

	DT50 (95% Confidence Intervals) [hours]
Temperature [°C]	pH 4	pH 7	pH 9
20	2.9 (2.0 to 3.7)	4.3 (1.4 to 7.1)	5.4 (4.7 to 6.1)
40	0.20 (0.06 to 0.35)	0.77 (0.51 to 1.02)	1.6 (1.3 to 1.9)
50	0.27 (0.22 to 0.32)	0.32 (0.23 to 0.41)	0.56 (0.48 to 0.63)

 

 

Description of key information

Hydrolysis study conducted in accordance with OECD Guideline 111.

The preliminary test (Tier 1) and main study (Tier 2) were performed for the determination of the rate of hydrolysis of Formaldehyde, oligomeric reaction products with acetone and diphenylamine at pH values normally found in the environment (pH 4-9). Hydrolysis behaviour was investigated for the m/z associated with diphenylamine and for an m/z of a higher-molecular-weight reaction product. At all temperatures, non-linear relationships were observed. Accordingly the model for pseudo-first order reactions was not applicable and half-life times of the test item could not be calculated.

Additional information

Acquiring m/z 170 -> m/z 93 the DT50 of the test item were:

	DT50 (95% Confidence Intervals) [hours]
Temperature [°C]	pH 4	pH 7	pH 9
20	234 (120 to 349)	467 (-37 to 971)	532 (193 to 872)
50	28 (25 to 31)	26 (23 to 30)	17.9 (15.6 to 20.2)
60	2.2 (1.8 to 2.6)	1.9 (1.6 to 2.1)	2.3 (2.0 to 2.6)

 

Acquiring m/z 391.2 -> m/z 182 the DT50 of the test item were:

	DT50 (95% Confidence Intervals) [hours]
Temperature [°C]	pH 4	pH 7	pH 9
20	2.9 (2.0 to 3.7)	4.3 (1.4 to 7.1)	5.4 (4.7 to 6.1)
40	0.20 (0.06 to 0.35)	0.77 (0.51 to 1.02)	1.6 (1.3 to 1.9)
50	0.27 (0.22 to 0.32)	0.32 (0.23 to 0.41)	0.56 (0.48 to 0.63)