4,4'-methylenebis(2,6-xylidine)

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

12 - 20 Mars 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

The study was conducted according to an internationally recognised method, and under GLP. No deviation was reported. The test substance is adequately characterised. Therefore full validation applies.

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Version / remarks:

1995

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Version / remarks:

2014

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

GLP compliance programme (inspected on 13 and 14 October 2014 / signed on 08 April 2015)

Type of method:

flask method

Key result

Water solubility:

27.02 mg/L

Temp.:

20 °C

pH:

6.3

Findings

Measurements during Equilibration

The data which was acquired during equilibration time (flask 1A-C, days 1 – 7) is presented in the following table:

Day	Temperature [°C]	pH*	Area Test Item [pA*s]	Area ISTD [pA*s]	Mean Conc. test item [mg/L]	Difference to previous sample [%]
1	20.5	6-7	620.0 717.5	2496.9 2539.5	21.81	-
2	20.0	6-7	744.5 745.9	2547.2 2538.6	23.86	+9.4
3	20.0	6-7	816.0 767.4	2461.1 2346.6	26.51	+11.1
5	20.5	6-7	777.0 825.9	2435.1 2548.6	26.16	-1.3
6	20.5	6-7	853.6 835.3	2448.7 2467.2	27.65	+5.7
7	20.5	6-7	847.4 841.1	2479.2 2519.9	27.26	-1.4

*measured via pH paper

 

After the analysis of the sample of day 7, the plateau was considered as reached.

Measurements at Plateau

Flask	Temperature [°C]	pH*	Area Test Item [pA*s]	Area ISTD [pA*s]	Mean Conc. test item [mg/L]
2	19.5	6.46	871.4 849.3	2465.4 2447.4	28.10
3	19.5	6.15	752.1 721.2	2493.7 2489.7	24.39
4	19.5	6.20	779.9 847.3	2442.2 2552.0	26.44

*measured via calibrated pH meter

 

A standard deviation of 1.86 mg/L was calculated in the flasks 2 – 4, giving a relative standard deviation of 7.1 %.

Results

The measurements of days 3 – 7 (flasks 1A – 1C) and flasks 2 – 4 were used for calculation as the plateau was not reached on days 1 and 2.

Measurements used for Calculation of Solubility:

Day	Flask	Concentration [mg/L]	Total Mean [mg/L]	Total Standard Deviation [mg/L] (RSD* [%])
3	1C	26.51	27.02	0.77 (2.8 %)
5	1A	26.16
6	1B	27.65
7	1C	27.26
7	2	28.10
7	3	24.39**
7	4	26.44

*RSD = relative standard deviation

**the value was stated as an outlier (Grubbs test) and was not used in the calculation of the mean

 

Mean at the plateau is 27.02±0.77 mg/L.

 

Discussion

The solubility of the test item in water was determined from the measured concentrations of the test item in the filtrated and extracted test solutions.

The measurements of days 3 – 7 (flasks 1A – 1C) and flasks 2 – 4 were used for calculation as the plateau was not reached on days 1 and 2. Furthermore, the value from the flask 3 was stated as an outlier (Grubbs test) and was not used in the calculation of the mean.

Standard deviation within the sampling days as well as all over the plateau was very low. The water solubility of the test item was stated as 27.02 ± 0.77 mg/L.

No observations arousing doubts concerning the accuracy of the results and the validity of the study were made.

All the chromatograms are in the experimental report.

Conclusions:

The water solubility of the test item in demineralized double distilled water was determined to be :
27.02 ± 0.77 mg/L at 20.0 ± 0.5 °C

Executive summary:

The water solubility of the test item was determined according to OECD 105 resp.EU A.6 using flask method under GLP.

The solubility of the test itemin water was determined by measurement of the test item concentration in the filtrated and extracted test solutions using GC/FID.

The preliminary test which is described in the guideline wasestimated during validation of the analytical method, based on SANCO 3029 criteria as 29 mg/L (measured in a solution with the concentration of the test item 1000 mg/L in demineralised water). Therefore, the flask method was used in the main test.

In the main test, 150 mg/L of the test item were used to prepare a saturated solution (in the guideline, about fivefold saturation is proposed). Four vessels (1C (for the sampling point 72 h) and 2 – 4) were set onto the shaking apparatus immediately. After 24 ± 2 hours, flask 1B (for the sampling point 48 h) and after 48 ± 2 hours, flask 1A (for the sampling point 24 h) were set on the shaker and all flasks were shaken for further 24 ± 2 hours at room temperature (20.0 ± 0.5 °C). Then, flasks 1A - 1C were taken from the shaker, samples were taken, membrane filtered, extracted and analysed via GC/FID. Due to an upward tendency, the test was prolonged and the flasks 1A – 1C were measured on day 7 getting the values of days 5 – 7. Because of a difference of less than 15 % in the concentrations on days 6 and 7 and no upward tendency, the test was finished on day 7.

No Tyndall effect could be observed in the filtrated solutions indicating that no undissolved particles are present.

The measurements of days 3 – 7 (flasks 1A – 1C) and flasks 2 – 4 were used for calculation as the plateau was not reached on days 1 and 2. Furthermore, the value from the flask 3 was stated as an outlier (Grubbs test) and was not used in the calculation of the mean.

Description of key information

The water solubility of the test item in demineralized water was determined to be: 27.02 ± 0.77 mg/L at 20.0 ± 0.5 °C

Key value for chemical safety assessment

Water solubility:

27.02 mg/L

at the temperature of:

20 °C

Additional information

A fully reliable experimental study, conducted according to a recognized OECD/EC method and under GLP, is available. Therefore, it is considered as a key study, and the result is retained as key data.