Benzenamine, N-phenyl-, styrenated

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:

2016-03-18 - 2016-04-01 (experimental phase)

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:

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

Deviations:

no

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))

Version / remarks:

Method C.19 Adsorption Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Media:

other: virtual estimation via HPLC using reference items for soil or sewage sludge matrices

Radiolabelling:

no

Test temperature:

column temperature: 30°C

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: HPLC System: Agilent Technologies 1100 series, incorporating autosampler and workstation
- Type, material and dimension of analytical (guard) column: Phenomenex Luna CN 5 μm 100 Å (150 x 4.6 mm), 30°C
- Detection system: UV detector, wavelength: 210 nm for dead time and reference items, 288 for test item

MOBILE PHASES
- Type: 55:45 (v/v) methanol:purified water
- Experiments with additives carried out on separate columns: no
- pH: 6.34
- Solutes for dissolving test and reference substances: methanol
Due to the high affinity of some of the test item isomers for the HPLC column stationary phase, it was necessary to amend the mobile phase composition to 100% methanol to achieve complete elution. This was performed at a time (24 to 25 min) greater than the retention time of the highest log Koc reference item, such that the test item isomers eluted by the amended mobile phase demonstrated a log Koc value greater than 5.63.


DETERMINATION OF DEAD TIME
- Method: by inert substances which are not retained by the column
The dead time was determined by measuring the retention time of formamide (purity 99.94%, 620 mg/L solution in 55:45 (v/v) methanol:purified water).

REFERENCE SUBSTANCES
- Identity:
Reference Item Purity* (%) Concentration (mg/L)
Acetanilide 99+ 120
Phenol 99.9 143
Atrazine 99.1 107
Isoproturon >98.0 163
Triadimenol 98.0 106
Linuron 99.7 100
Naphthalene 99+ 114
Endosulfan-diol 99.9 160
Fenthion 97.9 152
α-Endosulfan 99.6 101
Phenanthrene ≥99.5 125
Diclofop-methyl 99.1 133
DDT 98.7 144

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 10µl of a 256 mg/L solution
- Quantity of reference substances: 10µl, solution see above

REPETITIONS
- Number of determinations: duplicates

EVALUATION
- Calculation of capacity factors k': The capacity factors (k') for the reference items were calculated from the retention time data of the dead time and reference item solutions using Equation k' = (tr - t0) / t0
k' = capacity factor, tr = retention time (min), t0 = dead time (min)
- Calculation of retention times: determined
- Determination of the log Koc value: The log10 Koc value was determined using the following Equation with reference to the calibration curve: Log10Koc = (log10k' - A) / B
Koc = adsorption coefficient, k' = capacity factor, A = intercept of the calibration curve, B = slope of the calibration curve

Key result

Sample No.:

#1

Type:

log Koc

Remarks:

Peak 1

Value:

4.77 dimensionless

pH:

6.34

Temp.:

30 °C

Remarks on result:

other: Koc = 5.94 x 10exp4

Key result

Sample No.:

#2

Type:

log Koc

Remarks:

Peak 2

Value:

> 5.63 dimensionless

pH:

6.34

Temp.:

30 °C

Remarks on result:

other: Koc > >4.27 x 10exp5

Key result

Sample No.:

#3

Type:

log Koc

Remarks:

Peak 3

Value:

> 5.63 dimensionless

pH:

6.34

Temp.:

30 °C

Remarks on result:

other: Koc > >4.27 x 10exp5

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): y = 0.4037x - 1.3118; R² = 0.9808
- Graph of regression line attached
- Average retention data for test substance:
Peak 1: 11.878 min
Peak 2: 27.865 min
Peak 3: 28.295 min

Validity criteria fulfilled:

yes

Remarks:

The calibration curve for the reference items showed good first order correlation (R² = 0.9808) and retention times between duplicate injections were consistent, indicating that the HPLC method was valid for the estimation of the Koc of the test item.

Conclusions:

The study was conducted under GLP according to OECD guideline 121 on the registered substance itself without deviations. The method is to be considered scientifically reasonable with no deficiencies in documentation. The adsorption coefficient (Koc) of the test item has been determined to be in the range from 5.94 x 10exp4 to greater than 4.27 x 10exp5, log10 Koc from 4.77 to greater than 5.63. The test item can therefore be classified as immobile.

Executive summary:

The adsorption coefficient (Koc) of Benzenamine, N-phenyl-, styrenated CAS No. 68442-68-2 has been determined to be in the range from 5.94 x 10exp4 to greater than 4.27 x 10exp5, log10 Koc from 4.77 to greater than 5.63, using the HPLC screening method. The procedure was designed to be compatible with Method C.19 Adsorption Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 121 of the OECD Guidelines for Testing of Chemicals, 22 January 2001, under GLP, and to satisfy the data requirements of REACH Regulation (EC) No 1907/2006. The test item can therefore be classified as immobile.

Description of key information

The adsorption coefficient (Koc) is in the range from 5.94 x 10exp⁴ to greater than 4.27 x 10exp⁵, log10Koc from 4.77 to greater than 5.63 (HPLC screening method, OECD 121, GLP)

Key value for chemical safety assessment

Koc at 20 °C:

59 400

Additional information

[LogKoc: 4.77]