N,N’-di[3-(p-toluene sulfonyl)oxy]phenyl urea

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

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))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Radiolabelling:

no

Test temperature:

25 +/- 1°C

Details on study design: HPLC method:

Performance: The test item is in its undissociated form in the pH range 3 to 9 and accordingly the test was performed using the buffer solution at pH7 as an eluent.

Measurement conditions:
Instrument: HPLC with built-in UV Vis spectrophotometer.
Software: LabSolutions CS (Shimadzu.
Column: Inertsil CN-3 (150 mm x 2.1 mm I.D., particle size 5 µm, GL Sciences)
Column temperature: 25°C
Eluent: Methanol/buffer solution (pH 7) [10 mmol/L potassium dihydrogen phosphate solution adjusted to pH 7 with 1 mol/L sodium hydroxide solution] (6/4 v/v)
Flow rate: 0.2 mL/min
Measurement wavelength: Reference item 210 nm, test item and solvent blank 260 nm
Injection volume: 2 µL
Test temperature: 25 +/- 1°C

Reference substances: Formamide (for dead time: t0, 200.9 mg), N,N-Dimethylbenzamide (10.3 mg), atrazine (10 mg), linuron (2.3 mg), 1,2,3-trichlorobenzene (10.3 mg), phenanthrene (10 mg), and DDT (10.3 mg). Methanol was used as the solvent with all reference substances.

Preparation of test solutions: The test sample (10.3 mg) was weighed with an electronic balance and then filled up 25 mL with methanol by ultrasonic irradiation. This solution (1 mL) was filled up to 10 mL with the eluent and the solution was used as a solvent blank.
Measurement of retention times for reference items, and making of regression line: The reference item solution was injected twice to the test equipment and the retention times of reference items were measured. The capacity factors (K) of reference items were calculated. A regression line was made by the method of least squares using the adsorption coefficient (logKoc) and the logarithmic values of the capacity factors for reference items. The capacity factor (K), teh slope of regression equation (a) and the intercept of regression equation (b) were rounded to three decimal places.

K = (tR - t0)/t0
tR: Retention time of reference item (min)
t0: Dead time (min) (average of two measurements)
Log Koc = a x log K + b
a: Slope of regression equation
b: Intercept of regression equation

Measurement of retention time for test item: The test item solution was injected twice to the test equipment and the retention time of test item was measured. The solvent blank was injected once to the test equipment. It was confirmed that no peak existed at the peak position of test item by analysis of solvent blank.
Injection order: Reference item solution (first time), Test item solution (first time), test item solution (second time), solvent blank, reference item solution (second time).
Calculation of adsorption coefficient: The adsorption coefficient of test item was not calculated using the regression equation of regression line, because the retention time of test item was longer than DDT (Log Koc = 5.63). Therefore, the Log Koc was regarded as > 5.63.

Sample No.:

#1

Type:

log Koc

Value:

> 5.63 dimensionless

pH:

7

Temp.:

25 °C

Matrix:

Methanol used as solvent

Details on results (HPLC method):

See Table in 'Any other information on results incl tables.' section for details.

Calculation table for adsorption coefficient by HPLC Method

		tR	K	Log K	Log Koc
Reference item	Formamide (1)	2.22	t0 =2.23
	Formamide (2)	2.23
	N,N-Dimethylbenzamide (1)	2.51	0.128	-0.892	1.52
	N,N-Dimethylbenzamide (2)	2.51	0.128	-0.892	1.52
	Atrazine (1)	2.85	0.281	-0.551	1.81
	Atrazine (2)	2.86	0.285	-0.545	1.81
	Linuron (1)	3.70	0.663	-0.179	2.59
	Linuron (2)	3.71	0.667	-0.176	2.59
	1,2,3-Trichlorobenzene (1)	4.46	1.004	0.002	3.16
	1,2,3-Trichlorobenzene (2)	4.47	1.009	0.004	3.16
	Phenanthrene (1)	6.98	2.137	0.330	4.09
	Phenanthrene (2)	6.99	2.142	0.331	4.09
	DDT (1)	11.04	3.962	0.598	5.63
	DDT (2)	11.06	3.971	0.599	5.63
Test item	A	12.70	-	-	> 5.63
	B	12.69	-	-	> 5.63
	(A, B: Individual measurement)			Average	> 5.63

Log Koc = 2.684 x log K + 3.440

r = 0.962

Validity criteria fulfilled:

not applicable

Conclusions:

The duplicate retention times of the test item and reference items were almost identical in all cases. Therefore, the results are judged to be valid. The Log Koc value was determined to be greater than the highest reference substance (> 5.63 at 25°C).

Description of key information

An OECD 121 study is available on the substance. As the value was screened as > 5.63 (greater than the highest reference substance value) no key value for chemical safety assessment is included.