1-Octanol, reaction products with phosphorus oxide (P2O5), potassium salts

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:

24 July 2018 to 10 August 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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:

2016

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

GLP compliance:

yes

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Specific details on test material used for the study:

Purity: UVCB; solid matter 41.4%

Radiolabelling:

no

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: Acquity UPLC system (UPLC-MS/MS)
- Type, material and dimension of analytical column: Acquity UPLC HSS Cyano; 100 mm x 2.1 mm i.d., dp = 1.8 μm
- Detection system: Detector 1: Acquity UPLC TUV detector; Detector 2: Xevo TQ-S mass spectrometer

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

DETERMINATION OF DEAD TIME
- Method: by inert substances which are not retained by the column

REFERENCE SUBSTANCES
- Identity:
Acetanilide
Monuron
2,5-Dichloroaniline
Naphthalene
Benzoic acid phenylester
Fenthion

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 5 µL
- Quantity of reference substances: 5 µL

REPETITIONS
- Number of determinations: injected in duplicate

Analytical monitoring:

no

Sample No.:

#1

Type:

log Koc

Value:

1.15 dimensionless

Remarks on result:

other: Di ester

Sample No.:

#2

Type:

log Koc

Value:

1.19 dimensionless

Remarks on result:

other: Mono ester

Details on results (HPLC method):

For the di ester in the test item, two transitions (m/z 321.1 → m/z 78.8 and m/z 321.1 → m/z 208.9) were recorded. For the mono ester, one transition (m/z 208.9 → m/z 78.8) was recorded. All three transitions were used to determine the adsorption coefficient. In the chromatogram of the test solution at each transition, one major test item peak was observed.

The equation of the regression line was: log k’ = 0.431 x log Koc – 1.050 (r = 0.987, n = 12).

As this curve was constructed using UV detector responses and the test item was recorded using the MS detector, retention time of the test item had to be corrected for the difference in retention time between the UV and MS detector. The difference was determined using acetanilide. Under the conditions of the test, Acetanilide had a mean retention time of 0.993 minutes on the UV-detector and a mean retention time of 1.007 minutes on the MS-detector. The mean retention time of the response of the test item at each MRM was corrected for the difference in time (i.e. 0.015 minutes).

Validity criteria fulfilled:

yes

Conclusions:

The log Koc values of the test item at neutral pH were: log Koc 1.15 (Di ester), log Koc 1.19 (Mono ester).

Executive summary:

The test item is a UVCB that contains reaction products of 1-octanol and phosphorus pentoxide. The reaction products are mono‐, di‐ and trioctanyl phosphate esters and a mixture thereof. The adsorption/desorption properties of the UVCB test item were assessed following the OECD 117 HPLC method. The log Koc was determined to be 1.15 (di ester) and 1.19 (mono ester).

Description of key information

The test item is a UVCB that contains reaction products of 1-octanol and phosphorus pentoxide. The reaction products are mono‐, di‐ and trioctanyl phosphate esters and a mixture thereof. The adsorption/desorption properties of the UVCB test item were assessed following the OECD 117 HPLC method. The log Koc was determined to be 1.15 (di ester) and 1.19 (mono ester). Weighted mean value of 1.17 recommended for CSA input.

Key value for chemical safety assessment

Koc at 20 °C:

1.17