O,O-bis(2-ethylhexyl) hydrogen dithiophosphate

Water solubility

Administrative data

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

12 May - 19 Oct 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Version / remarks:

1995

GLP compliance:

yes (incl. QA statement)

Remarks:

Hess. Ministerium für Umwelt, Klimaschutz, Landwirtschaft und Verbraucherschutz, Wiesbaden, Germany

Type of method:

flask method

Test material

Test material information

Constituent 1

Reference substance name:

O,O-bis(2-ethylhexyl) hydrogen dithiophosphate

EC Number:

227-376-0

EC Name:

O,O-bis(2-ethylhexyl) hydrogen dithiophosphate

Cas Number:

5810-88-8

Molecular formula:

C16H35O2PS2

IUPAC Name:

O,O-bis(2-ethylhexyl) sulfanylphosphonothioate

Specific details on test material used for the study:

Storage conditions: at ambient temperature

Results and discussion

Water solubility

Water solubility:

24.1 mg/L

Conc. based on:

test mat. (dissolved fraction)

Temp.:

20 °C

pH:

2

Any other information on results incl. tables

Results
Preliminary Test
The test item shows under the conditions of the preliminary test a water solubility < 12.1 mg/L. Different runs of the main test showed that the test item reached the maximum of the water solubility after extended incubation times. Therefore the used concentration for the main test was not calculated under consideration of the preliminary test.

Main Test
Table 2 – Flask Parameter

Flask	Stirring time	Weight in 50 mL
	[h]	[g]
1	71	0.0097
2	95.5	0.0077
3	119.1	0.0103

Table 3 – Measured and calculated concentrations

Description	Dilution factor	Measured conc.	Calculated conc.	Average
	[/]	[µg/L]	[µg/L]	[mg/L]
Flask 1	20000	1.164	23280	24.06
Flask 2	20000	1.171	23420
Flask 3	20000	1.274	25480

 

Table 4 – Mean concentration and deviations

Overall mean	SD	RSD	Deviation between flask 2 and 3
[mg/L]	[mg/L]	[%]	[%]
24.06	1.23	5.12	8.80

 

The concentrations used for the calculation of the water solubility are not recovery corrected.

Table 5 – Concentration of spikes for recheck and recovery

Description	Amount of Spike	Measured Concentration of corresponding Sample	Measured Concentration of Spike	Recovery
	[µg/L]	[µg/L]	[µg/L]	[%]
Spike 1	0.9975	1.164	2.122	101.9
Spike 2	0.9975	1.171	2.128	101.9
Spike 3	0.9975	1.274	2.182	104.1

 

The recoveries are between 101.9 % and 104.1 %, indicating an acceptable accuracy of the analytical method.

Discussion
The water solubility of the test item was determined according to OECD Guideline 105 “Flask Method”.

Water solubility = 24.1 mg/L at pH 2.0

The criterion of the OECD 105 “If the concentrations measured in at least the two last vessels do not differ by more than 15%, the test is satisfactory.” This criterion is reached by this determination. Therefore the test is valid.