Cesium formate

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1997

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

A) The study was conducted according to OECD Guideline 107 and US EPA Product Properties Teat Guidelines: OPPTS 830.7550. B) Well-defined information were provided on: 1. Compositional information of the test substance (identity and purity) 2. Test methods used in the study 3. Description of methodologies 4. Test results 5. Definite conclusion

Qualifier:

according to guideline

Guideline:

OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7550 (Partition Coefficient, n-octanol / H2O, Shake Flask Method)

Deviations:

no

GLP compliance:

yes

Type of method:

shake-flask method to: flask method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

< -2.2

Temp.:

25 °C

pH:

>= 10 - <= 11

Details on results:

Preliminary test results:
The addition of octanol-saturated water and water-saturated octanol to the test substance resulted in complete visually observed dilution of the test substance. The estimated Pow and log Pow were 0.22 and 0.66 respectively.

Equilibration time determination:
Equilibration was achieved by the first sampling interval (1h) during which the test substance concentration in the nominal concentration of 0.0089 mol/L was found to be between 0.0088 and 0.0089 mol/L in the aqueous phase and 0.00004 mol/L in the octanol phase. 6 h was selected as a conservative equilibration period for the definitive test.

Analytical method results:
The measured concentrations of the test substance were between 0.0073 and 0.0075 mol/L in the aq. phase and below 0.00004 mol/L in the organic phase.
The calculated value of log Pow of the test substance was found to be less than -2.20 at 25±1°C.

 Details of preliminary results were as follows:

Cesium Formate weight (g)	Total volume added to sample (mL)	Approximate saturation concentration (mol/L)
Octanol-Saturated Water
0.120	0.100	6.7
0.127	0.100	7.1
0.111	0.100	6.2
Water-Saturated Octanol
0.103	0.400	1.4
0.104	0.400	1.5
0.110	0.400	1.5

Details of equilibration time determination:

Nominal concentration of Cesium Formate in aq. layer (mol/L)	Incubation period (h)	Measured concentration of Cesium Formate (mol/L)                               Octanol Aq. layer                   layer
0.0089	1	0.0088	0.000040
0.0089	2	0.0088	0.000040
0.0089	4	0.0089	0.000040
0.0089	6	0.0089	0.000040
0.0089	8	0.0089	0.000040
0.0089	16	0.0088	0.000040
0.0089	24	0.0088	0.000040
0.0089 mol/l Stock	0	0.0087	0.000040

Details of analytical method results:

Nominal concentration of Cesium Formate in aq. layer (mol/L)	Spiking ratio	Replicate	Measured concentration of Cesium Formate (mol/L)                   Octanol Aq. layer    layer layer		log Pow
0.0075	1:5	1	0.0074	0.000040	-2.13
		2	0.0073	0.000040	-2.26
	1:10	1	0.0074	0.000040	-2.13
		2	0.0073	0.000040	-2.26
	1:20	1	0.0074	0.000040	-2.13
		2	0.0075	0.000040	-2.27
	1:5	1	0.00074	0.000040	-1.27
		2	0.00074	0.000040	-1.27
	1:10	1	0.00074	0.000040	-1.27
		2	0.00078	0.000040	-1.29
	1:20	1	0.00074	0.000040	-1.27
		2	0.00080		-1.30

Conclusions:

Under the study conditions the log Pow for the test substance at 25±1°C is less than -2.20, therefore the test substance does not show the potential to bioconcentrate from water.

Executive summary:

A study was conducted to determine n-octanol/water partition coefficient (Pow) of the test substance according to OECD Guideline 107 and EPA OPPTS 830.7550 (flask method), in compliance with GLP. A preliminary test was conducted to determine the approximate solubility of the test substance in octanol-saturated water and water-saturated octanol. A second preliminary test was conducted to determine the equilibrium time to be employed during the definitive test. Definitive test was performed for the determination of n-octanol/water partition coefficient of the test substance. A stock solution of the test substance was prepared in octanol-saturated water to a concentration of 0.00075 mol/L. Water-saturated octanol was added to this stock solution in different ratios (1:5, 1:10 and 1:20) and 12 samples were prepared. The samples were centrifuged after an incubation period of 6 h in a rotary shaker and both the aqueous and the organic layers were analysed for the test item concentration in HPLC. In the first preliminary test addition of octanol-saturated water and water-saturated octanol to the test substance resulted in complete visually observed dilution of the test substance. The estimated Pow and log Pow were 0.22 and 0.66 respectively. In the second preliminary study the equilibration was achieved by the first sampling interval (1h). The data generated by the definitive test indicate that the test substance is highly soluble in the aqueous phase and less soluble in the octanol phase. Under the study conditions the log Pow for the test substance at 25±1°C is less than -2.20, therefore the test substance does not show the potential to bioconcentrate from water (Rondon, 1997).

Description of key information

Solid form: the partition coefficient was determined according to OECD Guideline 107.

Key value for chemical safety assessment

Log Kow (Log Pow):

-2.2

at the temperature of:

25 °C

Additional information

Solid form: Partition coefficient: log Pow < -2.20 at 25 °C