Dioctyl maleate, branched

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:

14 September 2017 to 16 May 2018

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

Media:

other: Zorbax CN (silica)

Specific details on test material used for the study:

Name: Bernel Ester DCM
Other names: bis(1-methylheptyl) maleate
Physical state: Clear liquid
CAS number: 85566-63-8
EC number 287-673-6
Molecular weight: 340.5 g/mol
Purity: 92.78%
Arrival date: 4 September 2017
Storage conditions: Room temperature (15 to 30°C)

Radiolabelling:

no

Test temperature:

25 °C

Details on study design: HPLC method:

The chromatographic characteristics of Bernel Ester DCM found in trial injections indicated that the log Koc value would be high. It was therefore considered that the most appropriate set of reference standards would be a selection from those with higher log Koc values.

The following reference standards, of known log Koc, were prepared in methanol and then diluted into mobile phase: Formamide (void marker), Acetanilide, Methyl benzoate, Naphthalene, 1,2,3 Trichlorobenzene, Phenanthrene and DDT. A solution of the test substance was prepared in methanol.

Two series of injections were made, each consisting of a single injection of Bernel Ester DCM, duplicate injections of the reference substances and triplicate injections of formamide (the void volume marker) using the following high performance liquid chromatography (HPLC) with ultraviolet (UV) detection conditions.

HPLC Agilent 1100
Column Zorbax CN, 5 μm, 250 x 4.6 mm
Column temperature 25C
Mobile phase Methanol:water, 65:35 v/v
Flow rate 1 mL/min
Injection volume 10 L
Detection wavelength 210 nm
Data collection time 10 minutes for formamide, acetanilide and methyl benzoate
20 minutes for Naphthalene, 1,2,3 Trichlorobenzene and phenanthrene
40 minutes for diluent, DDT, mixed standard and test substance

Analytical monitoring:

yes

Remarks:

UV

Sample No.:

#1

Duration:

2 min

Initial conc. measured:

ca. 33.192 other: ug/l

Sample No.:

#2

Duration:

2 min

Initial conc. measured:

ca. 33.328 other: ug/l

Key result

Sample No.:

#1

Type:

log Koc

Value:

> 4.86 - < 6.09 dimensionless

Temp.:

25 °C

Matrix:

Zorbax CN, 5 μm, 250 x 4.6 mm

Key result

Sample No.:

#2

Type:

log Koc

Value:

> 4.86 - < 6.07 dimensionless

Temp.:

25 °C

Matrix:

Zorbax CN, 5 μm, 250 x 4.6 mm

Details on results (HPLC method):

The test compound eluted as a single peak with a retention time within the range of retention times of the calibration substances. There were only minimal differences between the replicates of retention times for each of the reference and test substances, and between the two injection sequences. The resultant calculated values differed only to a small extent and therefore the results are considered as acceptable.

Adsorption and desorption constants:

The adsorption coefficient was found to be 5.36.

The quantities of each reference standard injected onto the column, statistical and analytical data are respectively shown in Table 5 and Table 6.
The plots of log K vs log Koc are shown in Figure 14 and Figure 15.
Typical chromatograms for Bernel Ester DCM and standards solutions are shown in Figure 16 to Figure 18.

Validity criteria fulfilled:

yes

Conclusions:

The procedures used conformed to those outlined in OECD Guideline 121. The adsorption coefficient was found to be 5.36.

Executive summary:

The procedures used conformed to those outlined in OECD Guideline 121. The adsorption coefficient was found to be 5.36.

Description of key information

The procedures used conformed to those outlined in OECD Guideline 121. The adsorption coefficient was found to be 5.36.

Key value for chemical safety assessment

Koc at 20 °C:

5.36

Additional information

Koc at 25 °C 5.36