Nonanoic acid, mixed esters with heptanoic acid, pentaerythritol and valeric 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:

8 to 20 December 2016

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

The analytical method used is the determination of the total organic carbon (TOC), which is forseen for the determination of solution of polymers in water (EU Method A.20) but not listed among the "preferred method" for the datermination of the water solubility, due to their incapacity to differentiate between the main substance and the impurities. The tested substance is a UVCB, therefore the concept of impurities is less relevant. The purity of the substance is stated to be 100%. In the final results, the water solubility caould not be precisely determined, since the amount of dissolved organic carbon was always below the limit of quantification of the method. This limit was determined to be 1.35 mg/L (equivalent to 2.01 mg/L of the test substance). The results can be therefore considered as reliable with restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

GLP compliance:

yes (incl. QA statement)

Remarks:

Rheinland-Pfalz - Landesamt für Umwelt, Wasserwirtschaft und Gewerbeaufsicht

Type of method:

flask method

Key result

Water solubility:

< 2.01 mg/L

Conc. based on:

test mat. (dissolved fraction)

Incubation duration:

7 d

Temp.:

20 °C

pH:

6.5

Water solubility:

< 1.35 mg/L

Conc. based on:

element (dissolved fraction)

Remarks:

Dissolved Organic Carbon

Incubation duration:

7 d

Temp.:

20 °C

pH:

6.5

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

Day	Temperature [°C]	pH*	Concentration DOC [mg/L]	Concentration test item [mg/L]
1	20.0	6-7	2.01	< 1.35
2	20.0	6-7	2.01	< 1.35
3	20.0	6-7	2.01	< 1.35
4	20.0	6-7	16.59	11.14
5	20.0	6-7	2.86	1.92
6	20.0	6-7	2.01	< 1.35
7	20.0	6-7	2.01	< 1.35

*measured via pH paper

 

The values on days 4 and 5 were stated as outliers due to a measured concentration of DOC in other flasks < LOQ. The repetition of the measurement on days 4 and 5 also showed the concentration > LOQ and the measurement was not used in the evaluation. Insufficient filtration or contamination of the test solutions during the sample preparation may be a reason for these values.

The measured value in the blank flask lay below the LOQ of TOC (< 1.35 mg/L).

 

The measured DOC concentrations are presented in the following table:

Flask	pH*	Concentration DOC [mg/L]	Concentration test item [mg/L]
2	6.69	< 1.35	< 2.01
3	6.31	< 1.35	< 2.01
4	6.48	< 1.35	< 2.01
5	6.41	< 1.35	< 2.01
6	6.61	< 1.35	< 2.01

 

Results

All measured values in the flasks 2 - 6 lay below the LOQ of TOC (< 1.35 mg/L) corresponding to the concentration of the test item in water < 2.01 mg/L.

As dependency of the water solubility on the amount of the test item added was always perceived for such complex substances as the test item, the solubility lower than 0.002 % of the test item was stated relating to the highest nominal concentration of the test item 100 g/L.

Description of key information

Water solubility: < 2.01 mg/L at 20 °C, pH = 6.5 (OECD guideline 105, flask method)

Additional information

The water solubility was measured using the Tocal Organic Concentration (TOC) approach. Four solutions of increasing nominal concentration were prepared (10.01 to 100.01 g/L). In all tests the Dissolved Organic Carbon (DOC) was below the limit of quantification of the method, which was determined to be 1.35 mg/L, corresponding to the concentration of the test item in water < 2.01 mg/L.