Bis(2-ethylhexyl) succinate

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 November 2012 to 19 December 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

GLP compliance:

yes

Type of method:

column elution method

Water solubility:

< 0 g/L

Temp.:

20.8 °C

pH:

7

Remarks on result:

other: Temperature ranged from 20.7 to 20.9 °C

Details on results:

Initially, seven to nine of the fractions were collected from the test system for each of the respective flow rates for the evaluation of the water solubility. The mean water solubility of bis(2-ethylhexyl) succinate was determined to be 0.00000182 ± 0.00000042 g/L at a flow rate of 25 mL/hour and 0.00000048 ± 0.00000022 g/L at a flow rate of 12.5 mL/hour using the column elution method. Due to the large difference (%D = 125 %) between these two readings (guideline criteria is 30 %), additional sample fractions were collected at both 12.5 and 25 mL/hr flow rates using several different columns. Measured concentrations were highly variable ranging from 0.00000017 to 0.0000034 g/L.

Turbidity values for all fractions ranged from 0.20 to 2.02 NTU for the samples analyzed. On each sampling occasion, the results of the turbidity measurements were also variable and exceeded the concurrent blank buffer measurements. To confirm that the turbidity was from the test material and not the column itself, turbidity measurements were taken using buffer and columns that contained glass beads but no test material. These turbidity readings including the column were higher than the buffer reading, but lower than a larger majority of the sample readings. There was no correlation between flow rate and the turbidity. There was also no apparent correlation between sample concentration and turbidity.

These results indicated that there was undissolved material present in the samples. It is likely that the undissolved material observed in the samples is attributed to break-through of the test material from the column due to the test material being a liquid. The highest measured concentration during this testing was 0.0000034 µg/L and therefore it can conservatively be estimated that the water solubility for this bis(2-ethylhexyl) succinate is < 0.00000500 g/L.

Table 1: Results for the determination of water solubility for Bis(2‑ethylhexyl) Succinate in pH 7 buffer

Replicate	Measured Water Solubility (g/L)
	Column Flow Rate
	25 mL/hour	pH^a	12 mL/hour	pH^a
pH 7 Buffer
1	0.00000343	7	<0.000000294	7
2	0.00000166	7	0.00000044	7
3	0.00000142	7	0.00000051	7
4	0.00000141	7	0.00000044	7
5	0.00000163	7	0.00000137	7
6	0.00000189	7	0.00000107	7
7	0.00000216	7	0.00000052	7
8	0.00000256	7
9	0.00000333	7
Mean:	0.00000182		0.00000073
Standard Deviation:	0.000000042		0.0000004
% Relative Standard Deviation:	23.00%		54.50%
Overall Mean:	0.00000132
Overall Standard Deviation:	0.00000075
Overall % Relative Standard Deviation:	57.10%

^a          pH measurements were recorded with EMD pH strips.

Conclusions:

Interpretation of results (migrated information): insoluble (< 0.1 mg/L)
Under the conditions of the study the water solubility of the test material was stipulated to be less than 0.00000500 g/L.

Executive summary:

The water solubility of the test material was determined in a GLP study which was conducted in accordance with the standardised guideline OECD 105. Undissolved test material was observed during preliminary testing via the flask method and so definitive testing was performed via the column elution method. Testing was performed at pH 7. Under the conditions of the study, the water solubility of the test material in pH 7 buffer was determined to be 0.00000182 and 0.00000048 g/L at flow rates of approximately 25 and 12 mL/hour, respectively. Turbidity values for all fractions ranged from 0.20 to 2.02 NTU for the samples analysed. These results indicated that there was undissolved material present in the samples. The presence of the undissolved material observed in the samples was attributed to break-through of the test material from the column due to the test material being a liquid. Due to the inconsistency of the concentration results for the 25 and 12 mL/hr flow rates and the likely release of undissolved test material from the support matrix, as indicated by the turbidity results, the water solubility result for this study was reported as less than 0.00000500 g/L.

Description of key information

Experimental study conducted according to recognised testing guideline with GLP certification.

Key value for chemical safety assessment

Water solubility:

0 g/L

at the temperature of:

20 °C

Additional information

The water solubility of the test material was determined in a GLP study which was conducted in accordance with the standardised guideline OECD 105. Undissolved test material was observed during preliminary testing via the flask method and so definitive testing was performed via the column elution method. Testing was performed at pH 7. Under the conditions of the study, the water solubility of the test material in pH 7 buffer was determined to be 0.00000182 and 0.00000048 g/L at flow rates of approximately 25 and 12 mL/hour, respectively. Turbidity values for all fractions ranged from 0.20 to 2.02 NTU for the samples analysed. These results indicated that there was undissolved material present in the samples. The presence of the undissolved material observed in the samples was attributed to break-through of the test material from the column due to the test material being a liquid. Due to the inconsistency of the concentration results for the 25 and 12 mL/hr flow rates and the likely release of undissolved test material from the support matrix, as indicated by the turbidity results, the water solubility result for this study was reported as less than 0.00000500 g/L.

The study was performed in line with GLP and an accepted standardised guideline with a high level of reporting. The study was assigned a reliability score of 1 and considered suitable for assessment as an accurate reflection of the substance.

The available data are considered to be complete and the result determined, water solubility < 0.00000500 g/L at 20.7 - 20.9 °C (pH 7), was taken forward for risk assessment.