4-[[5-(anilino)carbonyl-2-methoxyphenyl]azo]-3-hydroxynaphthalene-2-carboxamide

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

The study was conducted between 13 September 2000 and 7 December 2000.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC))

Version / remarks:

(draft)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Specific details on test material used for the study:

Identity: ST463.
Appearance: magenta powder
Storage conditions: room temperature
Batch number: 6558
Expiry date: August 2001
Purity: 99.4%
Date received: 1 August 2000

Radiolabelling:

no

Test temperature:

30°C

Details on study design: HPLC method:

Procedure:
As the test substance is ionisable, the test was conducted at both pH 4 and pH 10 thus covering the range of environmentally significant pH values. The pH 4 test was conducted as follows:

In order to correlate the measured capacity factor (k) of the test material with its Koc, six reference materials were selected from a list of recommended compounds. These reference compounds were selected to have a log10Koc values between 1.4 and 5.4. An internal standard (formamide) with no retention on the HPLC column was used to determine the deadtime for the HPLC system. THe following reference mixture was prepared in HPLC mobile phase.

Reference substance Known log10Koc Concentration (mg/L)
I.D.S Deadtime only 6220
Phenol 1.43 486
Nitrobenzene 2.36 116
Naphthalene 3.04 108
2-Methylnapthalene 3.87 112
Anthracene 4.41 7.17
DDT 5.38 34.9

A solution of test substance (10.07 mg/l in demethyl sulpoxide:methanol (1:1 v/v)) was prepared and chromatographed in duplicate, bracketed by samples of the reference mixture, using the following conditions:

HPLC conditions:
Instrument: Hewlett Packard 1050 Liquid Chromatograph
Column: Hypersil 5 µm CPS (25 cm x 4.6 mm internal diameter)
Column temperature: 30°C
Mobile phase compostion: Methanol:pH 4 buffer (55:45 v/v)
Flow rate: 1 ml/min
Injection volume: 25 µm
Detector: UV set at 210 nm (reference mixture); UV set at 516 nm (test substance)
Internal deadtime standard (I.D.S): Formamide

pH 10 test:
The pH 10 test was conducted identically, with the exception that the mobile phase employed was methanol:pH 10 buffer (55:45 v/v).

The adsorption coefficient is deduced from the capacity factor (k) give by:
k = tr - t0 / t0
where:
tr is the measured time of sample of reference
t0 is the retention time of the internal deadtime standard.

Sample No.:

#1

Type:

log Koc

Value:

> 5.4 dimensionless

pH:

4

Temp.:

30 °C

Sample No.:

#2

Type:

log Koc

Value:

> 5.4 dimensionless

pH:

10

Temp.:

30 °C

Details on results (HPLC method):

pH 4 test:
The reference standards eluted in order of their log10Koc values. The test substance was longer retained than any of the reference standards and therefore has a log10Koc value of greater than 5.4.

pH 10 test:
As a pH 4, the test substance was found to have a log10Koc value of greater than 5.4.

Validity criteria fulfilled:

not applicable

Conclusions:

The test substance was found to have a log10Koc value of >5.4.

Executive summary:

The adsorption coefficient of the substance was determined using the HPLC method. The study was conducted to OECD guideline 121.

The test substance was found to have a log₁₀K_oc value of >5.4.

Description of key information

The adsorption coefficient of the substance was determined using the HPLC method. The study was conducted to OECD guideline 121.

The test substance was found to have a log₁₀K_ocvalue of >5.4.

Key value for chemical safety assessment

Koc at 20 °C:

251 189

Additional information

[LogKoc: 5.4]