Reaction mass of Benzenepropanal, 4-ethyl-α,α-dimethyl- and 3-(2-ethylphenyl)-2,2-dimethylpropanal

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:

10 May 2016 to 12 May 2016

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:

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:

May, 2008

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Media:

soil

Radiolabelling:

no

Test temperature:

30 ºC

Details on study design: HPLC method:

TEST SYSTEM
The determination was carried out using an HPLC screening method, 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. The test system utilized a high performance liquid chromatograph and a cyanopropyl reverse phase HPLC column containing lipophilic and polar moieties.

PREPARATION OF THE TEST SAMPLE SOLUTION
Test item (0.2501 g) was diluted to 50 mL with methanol to give a concentration of 5.00E+03 mg/L.

PREPARATION OF THE DEAD TIME SOLUTION
The dead time was determined by measuring the retention time of formamide (purity* 99.94%, 613 mg/L solution in a matrix of methanol: water (55:45 v/v)).

PREPARATION OF THE REFERENCE ITEM SOLUTIONS
Solutions of reference items (see following table) were prepared in methanol.

Reference Item Purity (%)* Concentration (mg/L)
Acetanilide 99+ 120
Atrazine 99.1 107
Phenol 99.9 143
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
* value quoted by supplier

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 1100 series, incorporating autosampler and workstation
- Column: Luna CN 5μm (150 x 4.6 mm id)
- Column temperature: 30 ºC
- Mobile phase: methanol: water (55:45 v/v)
- pH of mobile phase: 6.9
- Flowrate: 1.0 mL/min
- Injection volume: 10 μL
- Method of detection: UV at 210 nm for the deadtime and reference standards UV at 265 nm for the test item

CONSTRUCTION OF CALIBRATION CURVE
A calibration curve was constructed from the retention time data of the dead time and reference standard solutions. Each capacity factor (k') was calculated. A correlation of log k' versus log Koc of the reference standards was plotted using linear regression.

ADSORPTION COEFFICIENT
The capacity factor for each test item solution injection was calculated and the log10 Koc values determined, with reference to the calibration curve. The adsorption coefficient was calculated.

Key result

Type:

log Koc

Value:

3.01 dimensionless

Remarks on result:

other: Average of 2 constituents

Type:

Koc

Value:

> 860 - < 1 200 dimensionless

Remarks on result:

other: based on 2 constituents

Type:

log Koc

Value:

> 2.94 - < 3.08 dimensionless

Remarks on result:

other: Based on 2 constituents

Details on results (HPLC method):

ADSORPTION COEFFICIENT OF THE SAMPLE
The retention times, capacity factor and log10 Koc value determined for the sample are shown in the table under 'Any other information on results incl. tables'. The Log10 Koc for one peak is 2.94 and for the other peak 3.08 (Adsorption coefficients are 860 and 1.20E+03)

pH CONSIDERATIONS
In the absence of any relevant dissociating functional groups, no specific manipulation of the mobile phase pH was necessary to achieve an unionized form of the test item. Therefore the determination was performed at an unadjusted, approximately neutral pH.

Table: Retention times, capacity factor and log10 Koc value determined for the sample

Peak	Injection	Retention time (mins)	Capacity Factor (k’)	Log10 K’	Log10 Koc	Mean Log10 Koc	Adsorption Coefficient
1	1	3.980	0.728	-0.138	2.94	2.94	860
	2	3.975	0.726	-0.139	2.93
2	1	4.218	0.831	-8.03E-02	3.08	3.08	1.20E+03
	2	4.213	0.829	-8.14E-02	3.08

Validity criteria fulfilled:

yes

Conclusions:

The adsorption coefficient, log Koc is 3.01 an average of two peaks reflecting the two constituents of the substance.

Executive summary:

The adsorption coefficient of Floralozone was tested in an HPLC screening method OECDTG 121. The substance showed two peaks one peak of 860 (log Koc 2.94) and another one 1200 (logKoc 3.08). It is not clear which peak belongs to which constituent, therefore an average is of the two values will be used for the risk characterisation: Log Koc is 3.01.

Description of key information

The adsorption coefficient of Floralozone was tested in an HPLC screening method OECDTG 121. The substance showed two peaks one peak of 860 (log Koc 2.94) and another one 1200 (logKoc 3.08). It is not clear which peak belongs to which constituent, therefore an average is of the two values will be used for the risk characterisation: Log Koc is 3.01.

Key value for chemical safety assessment

Koc at 20 °C:

1 023

Additional information

[LogKoc: 3.01]