Octanoic acid, 6,8-dimercapto-

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

29.09.2000 - 07.12.2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient)

GLP compliance:

yes

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

1.9

Temp.:

20 °C

Remarks on result:

other: no pH specified

From the results of the double estimation of the retention times for the reference substances and the test substance a mean value was calculated. This values are summarised in table 2.

Table 2: Retentions times

Substance	Retention time 1	Retention time 2	Mean value retention time tR
Aniline	5.1	5.1	5.1
Phenol	5.2	5.2	5.2
Benzole	9.5	9.5	9.5
Atrazine	8.2	8.2	8.2
Biphenyle	21.1	21.0	21.1
Phenanthrene	28.7	28.6	28.7
Dihydrolipoic Acid	6.7	6.7	6.7

The dead time to was determined by the injection of thiourea. A value of 3.5 min was determined. The capacity factors were determined from to and tr according to the following equation: k = tr-to/to.

The determined capacity factors k as well as the associated log k and the log Pow values known from literature are summarised in table 3.

Table 3: Capacity factors k, log k and log Pow

Substance	Capacity factor (k)	Log k	Log Pow
Aniline	0.457	- 0.340	0.9
Phenol	0.486	- 0.313	1.5
Benzole	1.714	0.234	2.1
Atrazine	1.343	0.128	2.6
Biphenyle	5.029	0.701	4.0
Phenanthrene	7.200	0.857	4.5
Dihydrolipoic Acid	0.914	- 0.039

The logPow-values were plotted against the log k values and a linear regression was performed. After substitution of the determined log k value (log k = - 0.039) for the test substance Dihydrolipoic Acid in the linear equation (y = 2.7474 * x + 2.0198) the log Pow value of Dihydrolipoic Acid was calculated to be 1.9

Conclusions:

The partition coefficient of Dihydrolipoic Acid is 1.9.

Executive summary:

The partition coefficient (n-octanol/water) of Dihydrolipoic Acid was determined with the HPLC-Method. In this test the elution behaviour of the test substance was correlated with logPow-values from literature on a reverdes phase separation column. Therefore the retention times of 6 reference substances were determined and the known logPow-values were plotted according their capacity factors. With help of the calibration line the logPow it was possible to determine the corresponding logPow value of Dihydrolipoic Acid (log Pow = 1.9).

Description of key information

The partition coefficient (n-octanol/water) of Dihydrolipoic Acid was determined

with the HPLC-Method to be 1.9.

Key value for chemical safety assessment

Log Kow (Log Pow):

1.9

at the temperature of:

20 °C

Additional information

The partition coefficient (n-octanol/water) of Dihydrolipoic Acid was determined with the HPLC-Method. In this test the elution behaviour of the test substance was correlated with logPow-values from literature on a reverdes phase separation column. Therefore the retention times of 6 reference substances were determined and the known logPow-values were plotted according their capacity factors. With help of the calibration line the logPow it was possible to determine the corresponding logPow value of Dihydrolipoic Acid (log Pow = 1.9).