Esterification products of 2,2-dimethylpropane-1,3-diol with n-heptanoic acid and n-octanoic acid and n-decanoic acid

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

04 Sept-06 Dec 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7840 (Water Solubility)

Deviations:

not specified

GLP compliance:

yes (incl. QA statement)

Type of method:

column elution method

Key result

Water solubility:

92.9 µg/L

Conc. based on:

test mat.

Temp.:

20 °C

pH:

5.4 - 6.8

Main study

During the measurements a tendency to flow rate dependent water solubility was observed. The water solubility was calculated over the 12 mL/min repeat samples and the 6 ml/min samples, i.e. after the column elution method had reached equilibrium. The maximum difference (MD) on the mean values of the samples at these flow rates was ≤ 30%. Based on this, the water solubility of the test substance is given as the mean value of these measurements. The turbidity of the eluates was < 0.2 NTU. According to this, no undissolved particles were detected in the eluates. No test substance was detected in the samples from the blank column.

Flow rate [ml/h]	Sample No.	Concentration analysed					pH
		Individual [µg/l]	Mean^1 [µg/l]	CV [%]	Mean^2 [µg/l]	MD [%]
24                     12	1 2 3 4 5 6 7 8 9 10   1 2 3 4 5 6 7 8 9 10	100^3 109^3 122 132 124 124 131 141 143 142   181 178 183 190 203 197 218^4 230^4 240^4 297^4	132                     189	6.5                     5.3	160	35^5	5.8                     6.8

¹Mean of the concentrations obtained at one flow rate.

²Mean of the concentrations obtained at both flow rates.

³This value was not used for calculation of the mean because the system had not reached equilibrium yet.

⁴Obtained by extrapolation of the calibration curve. Value was not used for calculation of the mean.

⁵Based on this maximum deviation, the study was extended.

Flow rate [ml/h]	Sample No.	Concentration analysed					pH
		Individual [µg/l]	Mean^1 [µg/l]	CV [%]	Mean^2 [µg/l]	MD [%]
24 (repeat)                     12 (repeat)                   6	1 2 3 4 5 6 7 8 9 10     1 2 3 4 5 6 7 8 9 10   1 2 3 4 5 6 7 8 9 10	32.8 67.8 40 39.3 54.2 32.2 75.3 34.5 17.4 21.5     214^3 152^3 123 106 122 91 99 86 131 89   62.1 65.3 66.2 94.0 83.7 81.3 287^4 119 70.9 76.2	41.5                       106                     79.8	45                       17                     22	n.a                       92.9	n.a                       28	5.4                       6.7                     6.2

¹Mean of the concentrations obtained at one flow rate.

²Mean of the concentrations obtained at both flow rates.

³This value was not used for calculation of the mean because the system had not reached equilibrium yet.

⁴Outlier according to Dixon’s Q-test.

Results of method development HPLC-MS/MS for quantification of the test substance in water:

Specificity: The chromatogram of the test substance solution showed one test substance peak. The area of this peak was used as response in the calculations.

Linearity: The calibration line was constructed using all data points. There was a linear relationship between response and test substance concentration in the range of 0.200 - 30.0 µg/L (in end solution). Since the coefficient of correlation (r) was >0.99 and the back calculated accuracies of the data points were in the range 85 -115% the calibration line was accepted.

Statistical parameters of the calibration curve:

Slope: 971

Intercept: 16.9

Weighting factor: 1/concentration²

^{r: 0.997}

^{Accuracy and repeatability: The results of the accuracy samples are given below. Since the mean accuracy at each concentration level fell in the criterion 70 -110% and the coefficient of variation was </=20% the analytical method was accepted for the analysis of the test substance in water in the target concentration range of 0.01 -10 mg/L.}

^{Accuracy samples:}

Target concentration [mg/L]	Nominal concentration [mg/L]	Analysed concentration [mg/L]	Accuracy [%]	Mean accuracy [%]	Coefficient of variation [%]
0.01	0.0100	0.00971	97	99	2.1
	0.0100	0.0103	102
	0.0100	0.00988	99
	0.0100	0.00979	98
	0.0100	0.00995	99
10	9.98	9.40	94	95	1.8
	9.98	9.40	94
	9.98	9.27	93
	9.98	9.72	97
	9.98	9.36	94

Description of key information

92.9 µg/L at 20 °C, pH=5.4-6.8 based on read-across from supporting substance (structural analogue or surrogate).

Key value for chemical safety assessment

Water solubility:

92.9 µg/L

at the temperature of:

20 °C

Additional information

The water solubility of the substance Decanoic acid, mixed exters with beopentyl glycol and octanic acid (CAS 70693-32-2) was determine according to EU Method A.6 (Water Solubility) using the column elution method.