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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
23 July 2012 to 26 February 2013
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2013
Report date:
2013

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC))
GLP compliance:
yes (incl. QA statement)
Type of method:
HPLC estimation method
Media:
soil

Test material

Constituent 1
Chemical structure
Reference substance name:
Dimethyl octadecylphosphonate
EC Number:
246-904-0
EC Name:
Dimethyl octadecylphosphonate
Cas Number:
25371-54-4
Molecular formula:
C20H43O3P
IUPAC Name:
dimethyl octadecylphosphonate
Constituent 2
Reference substance name:
M-5925
IUPAC Name:
M-5925
Test material form:
other: waxy solid
Details on test material:
Identification: Dimethyl octadecylphosphonate (CAS No. 25371-54-4)
Batch: B12-5990
Purity: >98% dimethyl octadecylphosphonate
Description: White waxy solid
Storage conditions: room temperature, in the dark
Expiry Date: 18 July 2013
Radiolabelling:
no

Study design

HPLC method

Details on study design: HPLC method:
The determination was carried out using the HPLC screening method, designed to be compatible with OECD 121. The test utilised a high performance liquid chromatograph. A commercially available cyanopropyl reverse phase HPLC column containing lipophilic and polar moieties was used. The dead time was determined by measuring the retention time of thiourea at 600 mg/L solution in methanol:water (55:45, v/v). Solutions of reference standards recommended for the determination of the adsorption coefficient by HPLC based on soil adsorption data (acetanilide, phenol, atrazine, isoproturon, linuron, naphthalene, endosulfan-diol, fenthion, α-edosulfan, phenanthrene and DDT) at approximately 100 mg/l were prepared in methanol. The test item, dimethyl octadecylphosphonate (DMOP) was diluted in tetrahydrofuran to give a concentration of approximately 5 g/l.
The DMOP sample, dead time and reference standard solutions were injected in duplicate using the HPLC system and parameters detailed in the section below.

A calibration curve was constructed from the retention time data of the dead time and reference standard solutions.

The capacity factor and the log10Koc value were determined using the equations below:

Capacity Factor
The capacity factor was determined using the equation below:

k' = (tr - t0)/ t0

Where:
k' = capacity factor
tr = retention time (min)
t0= dead time (min)

Adsorption Coefficient
Log10Koc = (Log10 k' – A)/B

Where

Koc = adsorption coefficient
k' = capacity factor
A = intercept of the calibration curve
B = slope of the calibration curve

The capacity factors k' for the reference standards were calculated using the equation above.

Batch equilibrium or other method

Analytical monitoring:
not required

Results and discussion

Adsorption coefficientopen allclose all
Type:
log Koc
Value:
> 5.63
Type:
Koc
Value:
> 427 000

Results: HPLC method

Details on results (HPLC method):
The retention time of the dead time was 1.948 min.

Results: Batch equilibrium or other method

Adsorption and desorption constants:
The adsorption coefficient of the DMOP was been determined to be >427000, log10 Koc >5.63.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The adsorption coefficient of the test item has been determined to be >427000, log10 Koc >5.63.
Executive summary:

The adsorption coefficinet was determined using the HPLC screening method designed to be compatible with OECD Guideline 121. The test utilised a high performance liquid chromatograph and a commercially available cyanopropyl reverse phase HPLC column containing lipophilic and polar moieties. The dead time was determined by measuring the retention time of thiourea. Solutions of reference standards recommended for the determination of the adsorption coefficient based on soil adsorption data were analysed. The dimethyl octadecylphosphonate (DMOP) sample, dead time and reference standard solutions were injected in duplicate and a calibration curve was constructed from the retention time data of the dead time and reference standard solutions. 

As the slope of the calibration curve for the reference standards showed good first order correlation and as the retention times between duplicate injections for each solution was consistent, the HPLC method was considered valid for the determination of adsorption coefficient.

The adsorption coefficient of the DMOP was determined to be >427000, log10 Koc >5.63.