Registration Dossier

Administrative data

Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2014

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC))
GLP compliance:
yes
Type of method:
HPLC estimation method
Media:
soil

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: Dark Brown Liquid
Details on test material:
Identity: Cashew Nutshell Extract, Decarboxylated
Appearance: Dark brown liquid
Storage conditions: Room temperature
Lot number: RM-9359 MIXTURE
Purity: UVCB

Study design

HPLC method

Details on study design: HPLC method:
A liquid chromatograph, comprising a pulse-free pump, injection valve with injection loop and suitable detector, was used in conjunction with a commercially available analytical column packed with a solid phase containing a moderately polar stationary phase with lipophilic and polar moieties (e.g. cyano-propyl bonded phase). The following mobile phases were used:

- methanol/water (55/45% v/v)
- methanol/0.01M citrate-buffer pH 6.0 (55/45% v/v)

HPLC grade methanol and distilled water were used to prepare the eluting solvent. The mobile phase was degassed before use. If methanol/water mixtures were not appropriate, other organic solvent/water mixtures were tried, e.g. ethanol/water or acetonitrile/water mixtures.

Measurements were made on ionisable substances at selected pH values by appropriate buffering of the HPLC eluent. Isocratic elutions were employed and the temperature during the measurements were recorded.

A minimum of 6 standard reference compounds were injected and the retention times determined. At least one standard was above and one below the expected value of the test substance. Chemicals injected onto the column move along it by partitioning between the mobile phase and the stationary phase. The velocity of each component thereby depends on the degree of adsorption on the stationary phase. The dual nature of the stationary phase allows for interaction of polar and apolar parts of a molecule in a similar way as is the case for soil. This enables the relationship between the retention time on such a column and the adsorption coefficient on the organic parts of the soil to be established.

The capacity factor, k, was determined for reference compounds from the expression: k = (tr - t0)/t0; where tr is the retention time of the compound and t0 is the deadtime, i.e. the average time a solvent molecule needs to pass through the column. The deadtime was obtained using an unretained molecule, e.g. formamide, urea, thiourea or sodium nitrate. The corresponding logarithms of the capacity factors, log10k, was calculated and plotted as a function of log10Koc. The retention time of the test substance was determined in duplicate, and log10Koc calculated by interpolation of the calculated capacity factor on the calibration graph.

For very low and very high adsorption coefficients, extrapolation was necessary. Especially in these cases, care has been taken concerning the confidence limits of the regression curve and the validity of the extrapolation.

Batch equilibrium or other method

Details on test conditions:
Instrument: Agilent 1200 Series Liquid Chromatograph with Chemstation software
Column: HyperClone CN (CPS) (25 cm x 4.6 mm internal diameter)
Column temperature: 25ºC
Mobile phase composition: Acetonitrile:water (55:45 v/v)
Flow rate: 1.0 ml/minute
Injection volume: 20 µl
Detector: UV set at 210 nm

Results and discussion

Adsorption coefficient
Key result
Type:
log Koc
Value:
>= 4.4 - <= 5.7 dimensionless

Results: HPLC method

Details on results (HPLC method):
Soil adsorption: a log10Koc range of 4.4 to 5.7 was determined for the main components of the test substance.

Any other information on results incl. tables

A calibration plot of log10k versus log10Kocwas constructed for the reference standards. The logarithms of the capacity factors for the test substance were then calculated and the log10Kocvalues were determined by interpolation (Table 1).

The main components of the test substance were found to have log10Kocvalues between 4.4 and 5.7.

Table 1         HPLC determination of log10Koc

  

Sample

Component

tr(minutes)

k

log10k

log10Koc

 

 

 

 

 

 

Standard Run A

Acetanilide

3.356

0.208

-0.682

1.3

(t0= 2.778 minutes)

Nitrobenzene

4.071

0.465

-0.332

2.4

 

Naphthalene

4.725

0.701

-0.154

2.8

 

2-Methylnaphthalene

5.009

0.803

-0.095

3.9

 

Anthracene

5.564

1.003

0.001

4.4

 

DDT

8.085

1.910

0.281

5.6

 

 

 

 

 

 

Sample A

Test substance

5.899 - 8.619

1.121 - 2.099

0.050 - 0.322

4.4 - 5.7

(t0= 2.781 minutes)

 

 

 

 

 

 

 

 

 

 

 

Sample B

Test substance

5.897 - 8.619

1.123 - 2.103

0.050 - 0.323

4.4 - 5.7

(t0= 2.778 minutes)

 

 

 

 

 

 

 

 

 

 

 

Standard Run B

Acetanilide

3.358

0.208

-0.682

1.3

(t0= 2.780 minutes)

Nitrobenzene

4.072

0.465

-0.333

2.4

 

Naphthalene

4.727

0.700

-0.155

2.8

 

2-Methylnaphthalene

5.011

0.803

-0.096

3.9

 

Anthracene

5.566

1.002

0.001

4.4

 

DDT

8.088

1.909

0.281

5.6

 

 

 

 

 

 

 

Linear regression (based on mean of standard runs A and B): log10Koc= 4.70 log10k + 4.15

Applicant's summary and conclusion

Conclusions:
The main components of the test substance were found to have log10Koc values between 4.4 and 5.7.
Executive summary:

Soil adsorption: a log10Koc range of 4.4 to 5.7 was determined for the main components of the test substance.