Pirimiphos-methyl

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

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)

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Type of method:

flask method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

4.2

Temp.:

20 °C

pH:

>= 5 - <= 7

Details on results:

The log Kow of pure test substance at 20 °C is 3.9 in water buffered at pH 4 and 4.2 in purified water and water buffered at pH 5 and pH 7. Recoveries were in the range 91 % - 102 %. Test substance is a weak base (pl

Table1 Partition Coefficient - Purified Water

Replicate, ratio	C_OCT % w/v	C_AQ % w/v	Pow	Log Pow	Recovery %
1, 1:1	0.302	1.98E-5	15200	4.18	99
2, 1:1	0.305	2.00E-5	15200	4.18	100
1, 1:4	0.293	2.01E-5	14600	4.16	96
2, 1:4	0.303	1.98E-5	15300	4.18	99
1, 2:3	0.304	1.97E-5	15400	4.19	100
2, 2:3	0.289	1.94E-5	14900	4.17	95
		Mean [2 sig fig) (Sr)		4.2 (0.25 %)

Table 2 Partition Coefficient - pH 4 Buffered Water

Replicate, ratio	C_OCT % w/v	C_AQ % w/v	Pow	Log Pow	Recovery %
1, 1:1	0.300	3.87E-5	7750	3.89	96
2, 1:1	0.306	3.87E-5	7910	3.90	98
1, 1:4	0.294	4.38E-5	6710	3.83	94
2, 1:4	0.308	4.44E-5	6940	3.84	99
1, 2:3	0.304	4.07E-5	7470	3.87	98
2, 2:3	0.306	3.97E-5	7710	3.89	98
		Mean [2 sig fig) (Sr)		3.9 (0.75 %)

Table 3 Partition Coefficient - pH 5 Buffered Water

Replicate, ratio	C_OCT % w/v	C_AQ % w/v	Pow	Log Pow	Recovery %
1, 1:1	0.295	1.89E-5	15600	4.19	95
2, 1:1	0.312	1.88E-5	16600	4.22	100
1, 1:4	0.301	1.84E-5	16400	4.21	97
2, 1:4	0.298	1.86E-5	16000	4.20	96
1, 2:3	0.296	1.96E-5	15100	4.18	96
2, 2:3	0.299	1.92E-5	15600	4.19	97
		Mean [2 sig fig) (Sr)		4.2 (0.35 %)

Table 4 Partition Coefficient- pH 7 Buffered Water

Replicate, ratio	C_OCT % w/v	C_AQ % w/v	Pow	Log Pow	Recovery %
1, 1:1	0.288	1.93E-5	14900	4.17	92
2, 1:1	0.283	1.89E-5	15000	4.18	91
1, 1:4	0.288	1.80E-5	16000	4.20	92
2, 1:4	0.317	1.87E-5	17000	4.23	102
1, 2:3	0.304	2.31E-5	13200	4.12	98
2, 2:3	0.317	1.79E-5	17700	4.25	102
		Mean [2 sig fig) (Sr)		4.2 (1.1 %)

Conclusions:

The purified test substance has a log Kow = 4.2 (in purified water and water buffered at pH 5 and pH 7) at 20 °C.

Executive summary:

The 1-octanol / water partition coefficient (Pow) of the test substance has been determined in a GLP-compliant study in accordance with the EU Method A.8. and OECD TG 107 by using the shake-flask method. The octanol·water partition coefficient (log Pow) of pure test substance at 20 °C was 3.9 in water buffered at pH 4, and 4.2 in purified water and water buffered at pH 5 and pH 7.

Description of key information

Log Kow = 4.2 at 20 °C, flask method, OECD TG 107, Husband 1997

Key value for chemical safety assessment

Log Kow (Log Pow):

4.2

at the temperature of:

20 °C

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