2-(3,5-dimethylhex-3-en-2-yloxy)-2-methylpropyl cyclopropanecarboxylate

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:

From 19 May 2016 to 28 July 2016

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

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:

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:

2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Date of inspection: 23 and 24 May 2013 / Date of signature: 16 September 2013

Type of method:

HPLC estimation method

Media:

other: Reverse phase HPLC on cyanopropyl-modified silica stationary phase containing lipophilic and polar moieties - separation of reference substances with known Koc.

Specific details on test material used for the study:

Batch No. : SC00017257
Purity : 97.6%
Date of Expiry : 15 April, 2018

Radiolabelling:

no

Test temperature:

35°C
(The determination was performed at 35°C (temperature of the column), but the value obtained above can be considered to represent the value at an unspecified, probably ambient temperature since no mention is made in the guidelines of the temperature at which the tabulated reference substances log Koc values were determined. Adsorption coefficients of the test and reference substances are assumed to vary with temperature in the same way).

Details on study design: HPLC method:

EQUIPMENT
HPLC equipment, Perkin Elmer (series 200) HPLC system comprising:
- a high pressure pump (module N2910102, serial number 291N8051901A)
- an auto-sampler (module N2930100, serial number 293N8052404A)
- a column compartment (module N2601581, serial number OVH0802151130)
- a refractive index detector (series 200a, serial number 125829)
Column 250 mm x 4.6 mm, Nucleodur 100-5 CN-RP (Macherey-Nagel), serial number E15120578, batch 34514011
Flow rate 1.0 mL/min
Column temperature 35°C
Injected volume 100 µL

MOBILE PHASES
- Type: methanol/water 55/45 (v/v)

DETERMINATION OF DEAD TIME
- Method: Formamide is used as an unretained compound for the determination of the dead time t0.

REFERENCE SUBSTANCES
Individual solutions of these seven substances in methanol were prepared. On the day of the determination, a calibration mixture of these seven substances were prepared by mixing 2mL of each of the individual solutions and adding enough ultrapure water to obtain a solvent composition similar to the mobile-phase (11.45 mL)
- Identity: Formamide, 2-Nitrobenzamide, Methyl benzoate, Naphthalene, 1,2,3-Trichloro-benzene, Phenanthrene, 4,4-DDT.

HPLC PROCEDURE
A solution of the test substance was prepared (10.0 mg in 25 mL methanol/water 55/45 v/v). After equilibration of the HPLC system, the calibration mixture was injected first, followed by the test chemical solution twice and the calibration mixture again. Retention time tR were measured and averaged and the decimal logarithms of the capacity factors k were calculated. The linear regression parameters of the relationship log Koc = f(log k) were also calculated from the data obtained with the calibration mixture and therewith log Koc of the test substance was determined from its measured capacity factor.

REPETITIONS
- Number of determinations: 2

Key result

Sample No.:

#1

Type:

log Koc

Value:

3.7 dimensionless

Temp.:

35 °C

Key result

Sample No.:

#2

Type:

log Koc

Value:

3.7 dimensionless

Temp.:

35 °C

Details on results (HPLC method):

The chromatograms of the test substance show one peak at an average retention times of 10.42 minutes, corresponding to an adsorption coefficient (log value) of 3.7.

The determination was performed at 35°C (temperature of the column), but the value obtained above can be considered to represent the value at an unspecified, probably ambient temperature since no mention is made in the guidelines of the temperature at which the tabulated reference substances log Koc values were determined. Adsorption coefficients of the test and reference substances are assumed to vary with temperature in the same way.

Linear regression parameters: log Koc = a * log k + b
Crrelation coefficient r = 0.9466
a = 2.5156
b = 2.7784
See graph in "Illustration"

Table 5.4.1/1: Adsorption coefficient calculations

		Log Koc	tR1	tR2	tRmean	k	Log k
Reference substances	Formamide 2-Nitrobenzamide Methyl benzoate Naphthalene 1,2,3-Trichlorobenzene Phenanthrene 4,4-DDT	1.45 1.80 2.75 3.16 4.09 5.63	3.154 3.686 5.212 7.793 9.122 12.655 29.608	3.156 3.684 5.206 7.764 9.091 12.565 29.336	3.16 3.69 5.21 7.78 9.11 12.61 29.47	0.168 0.651 1.465 1.886 2.997 8.341	-0.775 -0.186 0.166 0.276 0.477 0.921
Test substance			10.418	10.421	10.420	2.3021 / 2.3030 k (mean) = 2.3025	0.3621 / 0.3623 Log k (mean) = 0.3622

tR1, tR2, tRm: retention times (1rst measurement, 2ndr measurement, average)

Validity criteria fulfilled:

yes

Conclusions:

log Koc = 3.7

Executive summary:

The adsorption coefficient (Koc) on soil and on sewage sludge of the test substance was determined by the HPLC method according to the OECD Guideline 121 with GLP compliance. The reverse phase High Performance Liquid Chromatography on cyanopropyl-modified silica stationary phase, containing lipophilic and polar moieties, is used. While passing through the column among with the mobile phase the test substance interacts with the stationary phase. As a result of the partitioning between the mobile and stationary phase, the test substance is retarded. The dual-composition of the stationary phase having polar and non-polar sites allows for interaction of polar and non-polar groups of a molecule in a similar way as it is the case for organic matter in soil or sewage sludge matrices. This enables the relationship between the retention time on the column and the adsorption coefficient on organic matter to be established.

The result is: log Koc = 3.7

Description of key information

OECD 121 (HPLC), GLP, key study, validity 2:

Log Koc = 3.7;

Koc = 5012 L/kg;

The registered substance is immobile in soils (according to P.J. McCall et al., 1981).

Key value for chemical safety assessment

Koc at 20 °C:

5 012

Additional information

To assess the adsorption potential of the registered substance, one key experimental study is available. This study was performed on the registered substance according to OECD Guideline 121 (HPLC screening method) under GLP conditions.

Solutions of reference substances were prepared in methanol for calibration: Formamide (for dead-time determination), 2 -Nitrobenzamide, Methyl benzoate, Naphthalene, 1,2,3 -Trichlorobenzene, Phenanthrene and 4,4 -DDT. On the day of the determination, a calibration mixture of these seven substances were prepared by mixing each of the individual solutions and adding enough ultrapure water to obtain a solvent composition similar to the mobile phase (methanol/water 55/45 v/v). A solution of the test substance was also prepared in the mobile phase.

After equilibration of the HPLC system, the calibration mixture was injected first, followed by the test chemical solution twice and the calibration mixture again. Retention time tR were measured and averaged and the decimal logarithms of the capacity factors k were calculated. The linear regression parameters of the relationship log Koc = f(log k) were also calculated from the data obtained with the calibration mixture and therewith log Koc of the test substance was determined from its measured capacity factor.

The chromatograms of the test substance show one peak at an average retention times of 10.42 minutes, corresponding to an adsorption coefficient log Koc value at 3.7 and a Koc value at 5012 L/kg. The determination was performed at 35°C (temperature of the column), but the value obtained above can be considered to represent the value at an unspecified, probably ambient temperature since no mention is made in the guidelines of the temperature at which the tabulated reference substances log Koc values were determined. Adsorption coefficients of the test and reference substances are assumed to vary with temperature in the same way.

In conclusion, the result indicates that the substance is immobile in soils (according to P.J. McCall et al., 1981¹).

 

¹McCall P.J., Laskowski D.A., Swann R.L., and Dishburger H.J., (1981), “Measurement of sorption coefficients of organic chemicals and their use, in environmental fate analysis”, in Test Protocols for Environmental Fate and Movement of Toxicants. Proceedings of AOAC Symposium, AOAC,

Washington DC.

 

Mobility classification scheme:

Range of Koc	Mobility class
0 - 50	Very high
50 - 150	High
150 - 500	Medium
500 - 2000	Low
2000 - 5000	Slightly
> 5000	Immobile

 

[LogKoc: 3.7, Koc = 5012]