A mixture of: disodium 6-[3-carboxy-4,5-dihydro-5-oxo-4-sulfonatophenyl)pyrazolin-4-yl-azo]-3-[2-oxido-4-(ethensulfonyl)-5-methoxyphenylazo]-4-oxidonaphthalene-2-sulfonate copper (II) complex; disodium 6-[3-carboxy-4,5-dihydro-5-oxo-4-sulfonatophenyl)pyrazolin-4-yl-azo]-3-[2-oxido-4-(2-hydroxyethylsulfonyl)-5-methoxyphenylazo]-4-oxidonaphthalene-2-sulfonate copper (II) complex

Adsorption / desorption

Administrative data

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14 May 1997 to 17 June 1997

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1997

Report date:

1997

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 106 (Adsorption - Desorption Using a Batch Equilibrium Method)

Deviations:

no

GLP compliance:

yes

Media:

soil

Test material

Test material information

Constituent 1

Reference substance name:

A mixture of: disodium 6-[3-carboxy-4,5-dihydro-5-oxo-4-sulfonatophenyl)pyrazolin-4-yl-azo]-3-[2-oxido-4-(ethensulfonyl)-5-methoxyphenylazo]-4-oxidonaphthalene-2-sulfonate copper (II) complex; disodium 6-[3-carboxy-4,5-dihydro-5-oxo-4-sulfonatophenyl)pyrazolin-4-yl-azo]-3-[2-oxido-4-(2-hydroxyethylsulfonyl)-5-methoxyphenylazo]-4-oxidonaphthalene-2-sulfonate copper (II) complex;

EC Number:

423-940-7

EC Name:

A mixture of: disodium 6-[3-carboxy-4,5-dihydro-5-oxo-4-sulfonatophenyl)pyrazolin-4-yl-azo]-3-[2-oxido-4-(ethensulfonyl)-5-methoxyphenylazo]-4-oxidonaphthalene-2-sulfonate copper (II) complex; disodium 6-[3-carboxy-4,5-dihydro-5-oxo-4-sulfonatophenyl)pyrazolin-4-yl-azo]-3-[2-oxido-4-(2-hydroxyethylsulfonyl)-5-methoxyphenylazo]-4-oxidonaphthalene-2-sulfonate copper (II) complex;

Cas Number:

85585-91-7

IUPAC Name:

4-[2-(7-{2-[4-(ethenesulfonyl)-2-hydroxy-5-methoxyphenyl]diazen-1-yl}-8-hydroxy-6-sulfonaphthalen-2-yl)diazen-1-yl]-5-oxo-1-(4-sulfophenyl)-4,5-dihydro-1H-pyrazole-3-carboxylic acid 4-[2-(8-hydroxy-7-{2-[2-hydroxy-4-(2-hydroxyethanesulfonyl)-5-methoxyphenyl]diazen-1-yl}-6-sulfonaphthalen-2-yl)diazen-1-yl]-5-oxo-1-(4-sulfophenyl)-4,5-dihydro-1H-pyrazole-3-carboxylic acid dicopper tetrasodium hydride

Test material form:

solid

Specific details on test material used for the study:

Identification: Pacified Reactive Black 31
Description: dark brown crystalline solid
Lot: 0942
Dates received: 1 May 1997
Storage conditions: room temperature

Radiolabelling:

no

Study design

Test temperature:

Not stated

HPLC method

Details on study design: HPLC method:

HPLC system: Hewlett-Packard 1050 (or equivalent) incorporating autosampler abd workstation

Column: Novapoak C18 4 µ (300 x 3.9 mm id)

Mobile phase: methanol: water (55/45 v/v), containing 0.5% w/v tetrabutylammonium bromide

Flow rate: 1.0 ml/min

UV detector wavelength: 565 nm

Injection volume; 150 µl

retention time: ~6-7 minutes

Batch equilibrium or other method

Analytical monitoring:

yes

Details on sampling:

Screening test: adsorption
An aliquot (0.0849 g) of test material was diluted to 100 ml with 0.017 M calcium chloride solution. This was further distilled by a factor of 102 with 0.017 M CaCl2 solution.

Sample control preparation and treatment
Duplicate wet soil/test solution mixtures, and a wet soil 0.01 M CaCl2 solution (blank) were prepared for each soil type. A control consisting of test solution with no soil was also prepared. Each sample was protected from light in order to minimise photo degradation.

Samples were shaken continuously for a period of time. Agitation was adequate to maintain the soil in suspension, but not so vigorous as to cause the breakdown of the soil structture.

After equilibration, the samples were centrifuged to separate the phases and an aliquot (20.0 ml) was taken for analysis by HPLC.

Details on test conditions:

Soil 1 - very strongly to strongly acidic soil (pH 4.5 - 5.5)

Soil 2 - moderately to slightly acidic soil (pH 5.5-6.5)

Soil 3 - slightly alkaline soil (pH 7.1- 8.0)

Each soil was characterised with repsect to pH, organic carbon content, particle size distribution, cation exchnage capacity and exchangeable cations.

The moistire content of each soil was determined by drying samples at approximately 105°C for a minimum of 12 hours.

Equilbration of each soil was determined by gently shaking the soil and glass double-distilled water together for a period of 24 hours pror to the start of the test.

Results and discussion

Adsorption coefficient

Adsorption coefficient 1

Key result

Sample No.:

#1

Type:

Koc

Value:

113 000 dimensionless

Temp.:

21 °C

Remarks on result:

other: Soil type 1: 99.3% test material adsorbed

Adsorption coefficient 2

Key result

Sample No.:

#2

Type:

Koc

Value:

43 400 dimensionless

Temp.:

21 °C

Remarks on result:

other: Soil type 2: 99.4% test material adsorbed

Adsorption coefficient 3

Key result

Sample No.:

#3

Type:

Koc

Value:

129 000 dimensionless

Temp.:

21 °C

Remarks on result:

other: Soil tyoe 3: 99.4% test material adsorbed

Any other information on results incl. tables

Desorption

Soil type % test material desorbed % Test material remaining on adsorbent after desorption step

1 <1.19 >98.8

2 <1.05 >99.0%

3 <1.04 >99.0%

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The soil adsorption coefficient (Koc) of Pacified Reactive Black 31 has been determined to be 9.49E+04, log10 Koc 4.98.

Executive summary:

The adsorption / desorption characteristics in three different soil types have neen determined in accordance with OECD Guideline 106. "Adsorption / Desorption", OECD Guidelines for the Testing of Chemicals, 12 May 1981.

The soil adsorption coefficient (Koc) of Pacified Reactive Black 31 has been determined to be 9.49E+04, log10 Koc 4.98.