Charcoal

Water solubility

Administrative data

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010-6-28 to 2010-10-29

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted in accordance with EC directive 440/2008, method A.6 "water solubility", dated 31. May 2008 under the GLP compliance.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

yes

Remarks:

Deionised water with TOC <1 ppm and conductivity below 0.1 µS/cm was used

Principles of method if other than guideline:

The column elution method is based on the elution of a test substance with water from a micro-column which is filled with the test material. The water solubility is given by the mass concentration of the eluate when this has reached a plateau as a function of time. For the determination of charcoal, a HPLC column was filled with 700 mg of the test item and eluted with a continuous flow of 25 mL/h. The first column volumes were discarded and then seven fractions were collected and determined by the analysis of total carbon (TC) using a carbon analyser.
In a second experiment, the flow rate was reduced to 13 mL/h and 2 mL fractions were collected and analysed accordingly.

GLP compliance:

yes

Type of method:

column elution method

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.: 19062009 1PP
Appearance: Charcoal typic
Composition: Charcoal, carbon content in the test item 85.6% (elementary analysis)
CAS-no.: 16291-96-6
EINECS-no.: 240-383-3
Purity: C-Fix: 73.3%
Expiry date: Dec. 2030
Storage: Room temperature 20±5 °C, keep away from humidity
Preparation:
20 g of the test item charcoal was finely ground and the fraction 100-500 µm was used fort the test.

Results and discussion

Water solubility

Water solubility:

< 1 mg/L

Temp.:

21.3 °C

Details on results:

All measurements lay below the limit of quantification (LOQ) of total carbon (TC) (1.87 mg/L).

Deviation from study plan:
A temperature of 21.3±0.2 °C instead of 20.0±0.5 °C was considered as uncritical due to the low solubility measured.

Any other information on results incl. tables

The analytical results are presented in the following tables:

 

Measurements at flow rate 24.68 mL/h

Sample #	TC [mg/L]	TC*of the test item [%]	Concentration of the test item [mg/L]	pH
1	2.88	85.6	3.36	6
2	1.77 (< LOQ)	85.6	< LOQ	6
3	1.41 (< LOQ)	85.6	< LOQ	6
4	0.91 (< LOQ)	85.6	< LOQ	6
5	0.82 (< LOQ)	85.6	< LOQ	6
6	1.11 (< LOQ)	85.6	< LOQ	6
7	0.63 (< LOQ)	85.6	< LOQ	6

 

Measurements at flow rate 12.64 mL/h

Sample #	TC [mg/L]	TC*of the test item [%]	Concentration of the test item [mg/L]	pH
8	0.74 (< LOQ)	85.6	< LOQ	6
9	0.87(< LOQ)	85.6	< LOQ	6
10	0.96 (< LOQ)	85.6	< LOQ	6
11	0.96 (< LOQ)	85.6	< LOQ	6
12	1.06 (< LOQ)	85.6	< LOQ	6
13	1.13 (< LOQ)	85.6	< LOQ	6
14	0.88 (< LOQ)	85.6	< LOQ	6

 

* The TC (total carbon) of the test item was measured by elementary analysis (not within this study; value was provided by the monitor.)

The value of sample 1 was considered as outlier. The experiment was finished after 14 consecutive fractions.

 

Solubility results:

13 of the 14 measured values lay below the limit of quantification (LOQ) of total carbon (TC)(1.87 mg/L). The single value lying above the LOQ was considered as outlier.

The concentration of the test item was therefore calculated from the LOQ of TC and the carbon content of the test item as < 2.18 mg/L.

The values of the TC content lay above the limit of detection of 0.5 mg/L. The mean of these values lay below 1 mg/L,calculated with value 4 -14. Value 1 -3 are not chosen for mean calculation because they lay out of the equilibrium according to the guideline (>30% difference). Therefore the water solubility of charcoal (Probe 1: C-Fix = 73.3%) is <1 mg/L.

 

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): slightly soluble (0.1-100 mg/L)
The water solubility of charcoal was <1.0 mg/L at 21.3±0.2°C.