Reaction products of 4-amino-5-hydroxynaphthalene-2,7-disulfonic acid, coupled twice with diazotized 2-[(4-aminophenyl)sulfonyl]ethyl hydrogen sulfate, sodium salts

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:

September 03, 2009 to September 10, 2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.19 (Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Liquid Chromatography (HPLC))

Deviations:

no

GLP compliance:

yes

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Radiolabelling:

no

Test temperature:

25 °C

Details on study design: HPLC method:

HPLC equipment: HPLC System Agilent 1100 series: HPLC pump G1311A, autosampler G1313A, column oven G1316A, degaser G1322A and UV/Vis detector G1314A by Agilent
Column: Stationary phase: LiChrospher 100 CN 5µm by Duratec (15408-07)
particle size: 5 µm, pore size: 100 Å
material: stainless steel, dimensions: 250 mm x  4.6 mm
column temperature: 25 °C
Mobile Phase: Methanol / KH2PO4 (c=0.05 mol/l) 50:50 % (v/v) (pH = 4.0), isocratic elution
Flow rate: 1.0 ml/min
Injection volume: 10 µl
Detection wavelength: 250 nm (dead time marker); 250 nm (calibration substances), 600 nm (test item)

Injection amounts:
Dead time marker: 224.4 µg
Calibration substances: 0.70 – 1.46 µg
Test item: 0.032 µg
The dead time marker was dissolved in methanol and diluted 0.1 to 1 in the mobile phase and injected as single standards twice. The calibration substances were dissolved in methanol and diluted 0.1 to 1 in the mobile phase and injected as single standards twice. The item was dissolved in methanol and diluted from 1 ml to 10 ml with methanol and again from 0.5 ml to 1 ml with buffer solution (c(KH2PO4) = 0.5 mol/l) and injected as single sample twice.

Determination of the Dead Time t0
Dead time marker tR in min
1. Measurement tR in min
2. Measurement tR in min
Mean
Formamide 3.24 3.24 3.24

Dead time: t0 = 3.24 min
Table 2: Calibration Data – 1. Measurement
(*from OECD guideline 121, adopted January 2001)
Calibration substance 1. Inj. tR in min k log k log KOC *
Acetanilide 4.19 0.29 -0.53 1.25
Atrazin 4.60 0.42 -0.38 1.81
Monuron 4.92 0.52 -0.29 1.99
Triadimenol 5.76 0.78 -0.11 2.40
Linuron 6.58 1.03 0.01 2.59
Pyrazophos 8.99 1.77 0.25 3.65
Diclofop-methyl 11.07 2.41 0.38 4.20
4’4 DDT 22.39 5.90 0.77 5.63

Analytical monitoring:

yes

Details on sampling:

The dead time marker was dissolved in methanol and diluted 0.1 to 1 in the mobile phase and injected as single standards twice. The calibration substances were dissolved in methanol and diluted 0.1 to 1 in the mobile phase and injected as single standards twice.

The item was dissolved in methanol and diluted from 1 ml to 10 ml with methanol and again from 0.5 ml to 1 ml with buffer solution (c(KH2PO4) = 0.5 mol/l) and injected as single sample twice.

Details on matrix:

not applicable - HPLC Method

Details on test conditions:

not applicable

Computational methods:

- Adsorption coefficient per organic carbon (Koc):
The HPLC method is based on the correlation between the retention of a substance on a reversed phase column packed with a commercially available cyanopropyl solid phase containing lipophilic and polar moieties and the adsorption coefficient KOC.
log Koc=a+bxlogk

Type:

log Koc

Value:

< 1.25

Details on results (HPLC method):

log KOC of the Test Item – 1. Measurement

Test Item 1. Inj. tR in min k Log k log KOC
Test substanc 2.52 -0.22 < -0.53 < 1.251)
*1): below log KOC value of the lowest calibration substance (acetanilide)


Calibration Data - 2. Measurement
(*from OECD guideline 121, adopted January 2001)
Calibration substance 2. Inj. tR in min k log k log KOC *
Acetanilide 4.20 0.29 -0.53 1.25
Atrazin 4.61 0.42 -0.38 1.81
Monuron 4.92 0.52 -0.29 1.99
Triadimenol 5.76 0.78 -0.11 2.40
Linuron 6.58 1.03 0.01 2.59
Pyrazophos 8.99 1.77 0.25 3.65
Diclofop-methyl 11.07 2.41 0.38 4.20
4’4 DDT 22.42 5.91 0.77 5.63



Table 5: log KOC of the Test Item – 2. Measurement
Test Item 2. Inj. tR in min k Log k log KOC
test substance 2.52 -0.22 < -0.53 < 1.251)
*1): below log KOC value of the lowest calibration substance (acetanilide)

log KOC of the Test Item

log KOC
1. Measurement <1.25
2. Measurement <1.25
Mean <1.25

Adsorption and desorption constants:

not applicable

Recovery of test material:

not applicable

Concentration of test substance at end of adsorption equilibration period:

not applicable

Concentration of test substance at end of desorption equilibration period:

not applicable

Transformation products:

no

Details on results (Batch equilibrium method):

not applicable

log K_OC of the Test Item

 

	log KOC
1. Measurement	<1.25
2. Measurement	<1.25
Mean	<1.25

Validity criteria fulfilled:

yes

Conclusions:

The log Kow is <1.25 for the test substance. It will not be adsorbed by organic carbon in soil and thus can be classified to be of very high mobility.

Executive summary:

The adsorption coefficient of the test item was determined in a GLP compliant study, performed according to the OECD Guideline for the Testing of Chemicals, No. 121, Estimation of the Adsorption Coefficient (Koc) on Soil and Sewage Sludge using High Performance Liquid Chromatography (HPLC), Adopted Test Guideline (January 2001) and the EC Directive 2001159/EC, C. 19, EC publication L 225, August 2001.

Using the HPLC method, the log of the adsorption coefficient (Koc) was estimated to be log Koc: <1.25, therefore Koc: < 17.8, indicating that the test item will not be absorbed by organic carbon in the soil. Using QSAR calculations correlating the Koc with water solubility or n-octanol/water partition coefficient, the average adsorption coefficient of the test item was estimated to be Koc = 11 (all regressions), confirming the very high mobility of the test item.

Description of key information

With a log Koc of <1.25 L/kg (equivalent to a Koc value of <18) the substance may be considered mobile. 

Key value for chemical safety assessment

Koc at 20 °C:

17.8

Additional information

The adsorption/desorption characteristics of the test substance were investigated in a GLP-compliant study performed in accordance with OECD Guideline 121 (HPLC Method) (RCC, 2005). In this study, all solutions were analysed with HPLC with UV-VIS detector, reversed phase column (LiChrospher 100 CN column) and an aqueous mobile phase (methanol/water solution (55/45 v/v)). The log k’ values of reference substances were plotted against their known log Koc values. The log Koc value for the test substance was calculated by substituting its mean log k’ in the calibration curve. Under the conditions of the test, the log Koc of the test substance was determined at ≤1.25 (equivalent Koc ≤18 L/kg) which indicates that the test substance is very mobile.Using QSAR calculations correlating the Koc with water solubility or n-octanol/water partition coefficient, the average adsorption coefficient of the test item was estimated to be Koc = 11 (all regressions), confirming the very high mobility of the test item.

[LogKoc: 1.25]