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Reference
Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
13/07/2018 to 30/07/2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
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))
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of method:
HPLC estimation method
Media:
other: cyanopropyl reverse phase HPLC column containing lipophilic and polar moieties
Specific details on test material used for the study:
Identification:
OK (640-2) (Furoxy Hydroxy)
CAS number: 56271-94-4
Appearance/Physical state: Cream colored solid
Batch: G317624
Purity: 94.905%
Retest date: 05 September 2018
Storage conditions: Approximately 4 °C in the dark
Radiolabelling:
no
Test temperature:
25 °C
Details on study design: HPLC method:
Test System
The determination was carried out by the HPLC screening method, using a procedure
designed to be compatible with Method 121 of the OECD Guidelines for Testing of
Chemicals, 22 January 2001.
The test system utilized a high performance liquid chromatograph. A commercially available
cyanopropyl reverse phase HPLC column containing lipophilic and polar moieties was used.

Performance of the Test

Preparation of sample solution
Test item (0.1003 g) was diluted to 100 mL with methanol. This solution was further diluted
as follows: 10 mL, plus 45 mL of purified water, and then diluted to 100 mL with methanol,
to give a concentration of 100 mg/L.

Preparation of dead time solution
The dead time was determined by measuring the retention time of formamide (purity
99.6%) of a 602 mg/L solution in mobile phase.

Preparation of reference standard solutions
Solutions of reference standards (see table below) were prepared in methanol.

Determination of retention time
The sample, dead time and reference standard solutions were injected in duplicate using the
following HPLC parameters:
HPLC System : Agilent Technologies 1200, incorporating workstation and autosampler
Detector type : variable wavelength (VW)
Column : Waters XSelect HSS Cyano 5µm (150 x 4.6 mm id)
Column temperature : 25 °C
Mobile phase : Methanol: pH 7 buffer solution* (55:45 v/v)
pH of mobile phase : 7.0
Flow-rate : 1.0 mL/min
Injection volume : 10 µL
VW detector wavelength : 210 nm (dead time and reference standards), 275 nm (sample)

* Specification: Disodium hydrogen orthophosphate anhydrous (3 mM), Potassium dihydrogen
orthophosphate (2 mM), Sodium chloride (2 mM)

Evaluation of Data

Capacity factor
The capacity factor for each reference standard was calculated using the following equation:
Equation 1:

k' = (tr-t0)/t0
where k' = capacity factor; tr = retention time (min); t0 = deadtime

Construction of the calibration curve
A correlation of log k' versus log Koc of the reference standards was plotted using linear
regression (Appendix 2). The capacity factors (k') for the reference standards were calculated
using the previous equation. Log10Koc values are those quoted in Method 121 of the OECD
Guidelines for Testing of Chemicals, 22 January 2001.

Adsorption coefficient
Initially the capacity factor of the test item was calculated using Equation 1. The adsorption
coefficient was then calculated using the following equation with reference to the calibration
curve (Appendix 2).

Equation 2:

log10 Koc = log10k' -A/B
where Koc= absorption coefficient; k' = capacity factor; A = intercept of calibration curve; B = slope of calibration curve

4.1.3.4 Classification
The mobility classification of the test item was obtained by comparing the calculated Koc
value to the mobility classes according to P.J. McCall, R.L. Swann, D.A. Laskowski,
S.M. Unger, S.A. Vrona and H.J. Dishburger “Estimation of Chemical Mobility in Soil from
Liquid Chromatography Retention Times”; Bull. Environm. Contam. Toxicol. 24, 190-195
(1980) as shown in the table below:
Key result
Sample No.:
#1
Type:
log Koc
Value:
< 1.25 dimensionless
pH:
7
Temp.:
25 °C
Key result
Sample No.:
#2
Type:
log Koc
Value:
< 1.25 dimensionless
pH:
7
Temp.:
25 °C
Details on results (HPLC method):
- Retention times of reference substances used for calibration: see table below
- Details of fitted regression line (log k' vs. log Koc): log k'= 0.3495 (logKow) - 0.7789 r2= 0.9438
- Graph of regression line attached- yes
- Average retention data for test substance: retention time 1.506 min; capacity factor <0.376; log10k' <-0.425; log10Koc<1.25

System Deadtime

Dead time

                               Retention Times (min)

Mean Retention Time

Injection 1

Injection 2

Formamide

1.973

1.973

1.973

Retention times, capacity factors and absorption coefficients of reference standards

Standard

Retention time (min)

Mean Retention Time (min)

Capacity factor (k’)

Log10 k’

Log10 Kow

Injection1

Injection2

Acetanilide

2.716

2.711

2.714

0.376

-0.425

1.25

Phenol

2.57

2.57

2.57

0.303

-0.519

1.32

Atrazine

3.785

3.785

3.785

0.919

-0.037

1.81

Linuron

5.51

5.51

5.51

1.793

0.254

2.59

Naphthalene

4.752

4.752

4.752

1.409

0.149

2.75

Endosulfan-diol

6.686

6.706

6.696

2.394

0.379

3.02

Fenthion

8.314

8.29

8.302

3.208

0.506

3.31

a-Endosulfan

11.453

11.497

11.475

4.817

0.683

4.09

Diclofop-methyl

12.726

12.658

12.692

5.433

0.735

4.2

Phenanthrene

8.912

8.989

8.95

3.537

0.549

4.09

DDT

24.869

24.747

24.808

11.575

1.064

5.63

Validity criteria fulfilled:
yes
Conclusions:
The adsorption coefficient of the test item has been determined to be less than 17.8,
log10Koc < 1.25. The results classify the test item as having a very high mobility.
Executive summary:

The adsorption coefficient of OK (640-2) (Furoxy Hydroxy) has been determined to be less

than 17.8, log10Koc< 1.25, using the HPLC screening method, designed to be compatible

with Method 121 of the OECD Guidelines for Testing of Chemicals, 22 January 2001.  The

results classify the test item as having a very high mobility.

Description of key information

The adsorption coefficient of OK (640-2) (Furoxy Hydroxy) has been determined to be less

than 17.8, log10Koc< 1.25, using the HPLC screening method, designed to be compatible

with Method 121 of the OECD Guidelines for Testing of Chemicals, 22 January 2001.  The

results classify the test item as having a very high mobility.

Key value for chemical safety assessment

Koc at 20 °C:
17.8

Additional information