Propionamide

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018-11-20 to 2019-02-07

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient - Shake Flask Method)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

-0.7

Temp.:

23 °C

pH:

>= 5.4 - <= 5.6

Details on results:

Preliminary Test
The preliminary test at room temperature showed, that the octanol solubility of the test item was in the range of 58 g/L and 179 g/L.

Preliminary Test

The preliminary test at room temperature showed, that the octanol solubility of the test item was in the range of 58 g/L and 179 g/L.

 

Preliminary test for the octanol solubility

Total amount of added test item [g]	Volume of octanol [mL]	Stirring time at RT [min]	Remark
0.58	10	50	dissolved
1.79	10	165	not dissolved

 

With the water solubility of 3000 to 3500 g/L, and the solubility in octanol of 58 to 179 g/L, estimated from this preliminary test, the partition coefficient can be estimated to be between -1.3 and -1.7. For the determination of the log Pow in this range the shake flask method is recommended.

 

Main Test

The phases of the shake-flask-method were measured twice by means of HPLC.

 

Concentrations in the aqueous phases

separating funnel	pH values*1	measured concentration (g/L)	mean concentration*2 (mg/L)
1a	5.5	69.5 /66.3	339
1b	5.4	77.4/75.2	381
2a	5.4	68.0 /68.3	341
2b	5.6	65.6/63.9	324
3a	5.5	108.8/113.2	555
3b	5.5	111.4/108.4	549

*1 at a temperature of 23 °C

*2 under consideration of the dilution factor 5

 

Concentrations in the octanol phases

separating funnel	measured concentration	mean concentration
1a	66.2 /64.5	65.4
1b	64.2 /63.0	63.6
2a	59.4 /61.0	60.2
2b	53.4 /60.4	59.4
3a	103.0 / 101.0	102.0
3b	101.9 /105.2	103.5

The total amount of test item found in the two phases, the recovery rate and the partition coefficients are shown As 20 mL of the stock solution were added to each separating funnel, each funnel should contain 15 64 mg of the test item.

 

Results of the shake-flask-method

separating funnel	total amount of test item in the separating funnel (mg)	recovery rate (%)	Pew	log Pow
1a	14.33	95.1	0.193	-0.7
1b	16.52	105.6	0.167	-0.3
2a	16.04	102.6	0.177	-0.3
2b	15.32	93.0	0.134	-0.7
3a	15.13	97.1	0.134	-0.7
3b	15.13	96.7	0.133	-0.7
mean value				-0.7
standard deviation				<0.1

 

The recovery rate of the measured standard solutions was in the range from 96.3 % to 100.8 %, which shows a good accuracy of the analytical method.

Conclusions:

The partition coefficient of the test item was determined at 23 °C (pH 5.4 – 5.6) by means of the shake-flask-method to be log Pow = -0.7 ± <0.1.

Executive summary:

 A study was conducted in accordance with OECD TG 107 and Regulation (EC) No 440/2008 method A.8 to determine the partition coefficient of the test substance using the shake flask method. The equilibrium concentration of the test item in both phases was determined by means of UV/VIS. After adding the different amounts of stock solution, pre-saturated double distilled water and pre-saturated 1-octanol, the funnels were shaken for approx. 10 minutes in a shaking apparatus. After shaking the phases were allowed to separate in the funnels. Subsequently, 10 mL of each phase were centrifuged for 30 minutes at 20 °C and 15000 rpm. For the analytical measurement by means of UV/VIS spectroscopy the centrifuged clear water phases as well as the clear octanol phases were measured without prior dilution steps. The pH values of all water phases were measured. The phases of the shake-flask-method were measured twice. The partition coefficient of the test item was determined at 23 °C (pH 5.4 – 5.6) by means of the shake-flask-method to be log Pow = -0.7 ± <0.1.

Description of key information

The partition coefficient of the test item was determined at 23 °C (pH 5.4 – 5.6) by means of the shake-flask-method to be log Pow = -0.7 ± <0.1 (reference 4.7-1).

Key value for chemical safety assessment

Log Kow (Log Pow):

-0.7

at the temperature of:

23 °C

Additional information

A study was conducted in accordance with OECD TG 107 and Regulation (EC) No 440/2008 method A.8 to determine the partition coefficient of the test substance using the shake flask method. The equilibrium concentration of the test item in both phases was determined by means of UV/VIS. After adding the different amounts of stock solution, pre-saturated double distilled water and pre-saturated 1-octanol, the funnels were shaken for approx. 10 minutes in a shaking apparatus. After shaking the phases were allowed to separate in the funnels. Subsequently, 10 mL of each phase were centrifuged for 30 minutes at 20 °C and 15000 rpm. For the analytical measurement by means of UV/VIS spectroscopy the centrifuged clear water phases as well as the clear octanol phases were measured without prior dilution steps. The pH values of all water phases were measured. The phases of the shake-flask-method were measured twice. The partition coefficient of the test item was determined at 23 °C (pH 5.4 – 5.6) by means of the shake-flask-method to be log Pow = -0.7 ± <0.1.