Potassium hexadecyl hydrogen phosphate

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 2020-02-17 to 2020-02-27

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Version / remarks:

1995

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Key result

Water solubility:

18.6 mg/L

Conc. based on:

test mat.

Loading of aqueous phase:

28 mg/L

Incubation duration:

>= 48 - <= 72 h

Temp.:

20 °C

pH:

>= 6.25 - <= 6.37

Sample No.	1	2	3	4	5	6
Weighed amount of test item [mg]	7.15	6.86	6.44	6.75	6.90	6.88
Volume of water [mL]	250	250	250	250	250	250
Loading rate [mg/L]	28.60	27.44	25.76	27.00	27.60	27.52
Agitation time at 30°C [hours]	29.5	29.5	53.5	53.5	77.5	77.5
Equilibration time at 20°C [hours]	24	24	24	24	24	24
pH value of test item solution	6.32	6.27	6.34	6.25	6.32	6.37

 

Shaking time [Hours]	Measured concentration of test item in sample [mg/L]	Sample Preparation Factor	Determined concentration of test item in sample [mg/L]	Water solubility mean value [mg/L]	Overall mean ± Std. Dev. [mg/L]
29.5	0.758	20	15.2	15.9	-
29.5	0.828	20	16.6
53.5	0.852	20	17.0	17.6	18.6 ± 1.5
53.5	0.904	20	18.1
77.5	1.03	20	20.7	19.6
77.5	0.930	20	18.6

Conclusions:

The mean water solubility of the test item was determined to be 18.6 ± 1.5 mg/L at 20 °C and a pH value around 6.3.

Executive summary:

The water solubility was determined according to OECD Guideline No. 105 using the flask method with analysis by HPLC with MS/MS-detection. Six aliquots of the test item, were weighed into separate flasks. Two flasks were stirred for 24 h, 48 h and 72 h, respectively. The difference between the results obtained after the last two incubation days was 11 %. The acceptance criterium was therefore fulfilled and the study is valid. For calculation of the overall mean the measured concentrations of the last two incubation days were used. The first incubation period was not considered, because the difference between the first and last incubation period exceeded the 15 % criterion. The mean water solubility of the test item was determined to be 18.6 ± 1.5 mg/L at 20 °C and a pH value around 6.3.

Description of key information

The mean water solubility of the test item was determined to be 18.6 ± 1.5 mg/L at 20 °C and a pH value around 6.3.

Key value for chemical safety assessment

Water solubility:

18.6 mg/L

at the temperature of:

20 °C

Additional information

The water solubility was determined according to OECD Guideline No. 105 using the flask method with analysis by HPLC with MS/MS-detection. Six aliquots of the test item, were weighed into separate flasks. Two flasks were stirred for 24 h, 48 h and 72 h, respectively. The difference between the results obtained after the last two incubation days was 11 %. The acceptance criterium was therefore fulfilled and the study is valid. For calculation of the overall mean the measured concentrations of the last two incubation days were used. The first incubation period was not considered, because the difference between the first and last incubation period exceeded the 15 % criterion. The mean water solubility of the test item was determined to be 18.6 ± 1.5 mg/L at 20 °C and a pH value around 6.3.

The water solubility study from 2013 was disregarded due to significant methodological deficiencies. It is assumed that the reported slight turbidity of the solution corresponds to undissolved test item which lead to an overestimation of the concentration of dissolved test item.