Charcoal

Partition coefficient

Administrative data

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010-07-08 to 2010-07-09

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was performed according to the principles of GLP (GLP certificate included) and according to OECD GL 117.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)

Deviations:

no

Principles of method if other than guideline:

no aplicable

GLP compliance:

yes

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Test material

Test material information

Constituent 1

Reference substance name:

Charcoal

EC Number:

240-383-3

EC Name:

Charcoal

Cas Number:

16291-96-6

IUPAC Name:

Carbón vegetal

Details on test material:

Name charcoal
Batch no. DP 07.2008/1
Appearance charcoal typic
Composition charcoal
CAS No. 16291-96-6
EINECS-No. 240-383-3
Purity C-Fix: 788.7%
Expiry date 01. Dec. 2030
Storage room temperature 20 ± 5 °C, keep away from humidity

Study design

Analytical method:

high-performance liquid chromatography

Results and discussion

Partition coefficient

Type:

log Pow

Partition coefficient:

ca. 0.3 - <= 1.474

Temp.:

25 °C

pH:

ca. 5.5

Remarks on result:

other: Actually the determined log Pow is in the range of < 0.3 to 1.44

Any other information on results incl. tables

Table 2: Retention times, capacity factors k, and log Pow of the reference items

Compound	Retention Time (tr) Mean	Retention Time (tr) RSD	k	log k	log POW
	[min]	[%]
Thio urea	1.506	0.059	0.0000
2-Butanone	1.953	0.060	0.2969	-0.5274	0.30
Acetanilide	2.214	0.070	0.4701	-0.3278	1.00
Acetophenone	2.866	0.064	0.9032	-0.0442	1.70
Nitrobenzene	3.410	0.036	1.2645	0.1019	1.90
Benzene	4.824	0.098	2.2033	0.3431	2.10
Toluene	7.632	0.125	4.0677	0.6094	2.70

 

Calibration Results:                  

A calibration function (log k versus log P_OW, linear fit) was determined using the literature values for P_OWof the reference items and the retention times in the six determinations.

Dead time was 1.506 ± 0.001 minutes, with a relative standard deviation (RSD) of 0.059 %.

The RSDs of the retention times of the reference items were all below 0.5 %.

Equation of the regression line :

log k = 0.4843 * log P_OW– 0.7572 with a correlation coefficient r²= 0.9587

Chromatogram of the test item

The chromatogram of the test item yields five peaks, one main peak (peak 1), two riders (peak 2 and peak 3) and two smaller peaks (peak 4 and peak 5).

Using the determined equation of the regression line and the calculated capacity factors for the test item, the log P_OWfor each of the 3 determinations was calculated by the following equation: log P_OW = (log k + 0.7572) / 0.4843. The corresponding log Pow values (mean of 3 determinations) are given in the following table

 

Table 3: Retention times , peak areas and corresponding log Pow of each of the peaks arised

in the chromatogram of the test item

Peak	Mean Area [mAU*min] [1]	Rel. Area %	Mean retention time [min]	Log POW ±Stand. Dev.
1	2.7555	76.31	1.442	< 0.3
2	0.3336	9.24	1.840	0.213 ± 0.008
3	0.1192	3.3	2.312	1.003 ± 0.015
4	0.3599	9.97	2.869	1.474 ± 0.002
5	0.0428	1.19	7.148	2.748 ± 0.000

[1] mAU = milli absorbance units

These values are the means ± standard deviations of three independent determinations. The first peak lies within the dead time of the method and not within the range of log P_ow’s of the reference items. Therefore, the corresponding log P_ow should be stated as < 0.3 for peak 1. As peak 3 and 5 showed a relative area < 5%, they were considered as minor peaks and were not taken into account in the determination of log P_ow of the test item. It is thus concluded that the test item charcoal (Probe 3: C-Fix = 88.7%) has a log P_ow of < 0.3 -1.474.

Validity of the study

Table 4:     Validity criteria and results

Peak	Parameter	Criterion	Found	Assessment
1	Range (Max – Min log POW)	< 0.1	not calculable	not calculable
	Value within range of ref. items	0.30 - 2.70	not calculable*	not calculable
2	Range (Max – Min log POW)	< 0.1	0.016	valid
	Value within range of ref. items	0.30 - 2.70	0.213	not valid
3	Range (Max – Min log POW)	< 0.1	0.028	valid
	Value within range of ref. items	0.30 - 2.70	1.003	valid
4	Range (Max – Min log POW)	< 0.1	0.005	valid
	Value within range of ref. items	0.30 - 2.70	1.474	valid
5	Range (Max – Min log POW)	< 0.1	0.001	valid
	Value within range of ref. items	0.30 - 2.70	2.748	not valid

* This peak lies within the dead time of the method and not within the range of log P_OWs of the reference items. Therefore the corresponding log P_ow is stated as < 0.3.

** As there is only a minor deviation from this single validity criteria but all other validity criteria are met the study is considered to be valid.

Applicant's summary and conclusion

Conclusions:

It is concluded that the test item charcoal (Probe 3: C-Fix = 88.7%) has a log POW of < 0.3 -1.474. The result is related to the used charcoal extract (charcoal (Probe 3: C-Fix = 88.7%) with a nominal concentration of 224360 mg/L in methanol/water (75/25 % v/v) under the testing conditions (temperature = 25+1°C, pH = 5.5) used.