Triethyl phosphonoacetate

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 16 December 2011 to 3 September 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Study conducted in compliance with international and OECD standard guidelines under GLP conditions. The study report was well documented with all mandatory information included.

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

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))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

2011-08-31

Type of method:

HPLC estimation method

Media:

other:

Radiolabelling:

no

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: Agilent Technologies 1200 Series
- Type: XSelect HSS Cyano
- Type, material and dimension of analytical (guard) column:
Column dimension: 5µ (150 * 4.6 mmid)
Column temperature: 35°C
Flow-rate : 1.0 ml/min
- Detection system: Refractive index detector
- Detection system temperature : 40°C

MOBILE PHASES
- Type: methanol/water (55:45 v/v)
- Experiments with additives carried out on separate columns: no
- pH: 5.7
- Solutes for dissolving test and reference substances: * for standard reference solution (exception of acetanilide, phenol): methanol
* for acetanilide, phenol and test item solution :mobile phase

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

REFERENCE SUBSTANCES
- Identity: Acetanilide, Phenol, Isoproturon, Triadimenol, Linuron, Naphthalene, Endosulfan-diol, Fenthion, Phenanthrene, Diclofop-methyl, DDT

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column:10µl
- Quantity of reference substances:10µl
- Intervals of calibration (log Koc): 1.25 to 5.63

REPETITIONS
- Number of determinations:2

EVALUATION
- Calculation of capacity factors k': k'= (tr-t0)/t0 [tr=retention time and t0= dead time]
- Determination of the log Koc value: log Koc= (logk' -A)/B

Analytical monitoring:

not specified

Type:

Koc

Value:

< 17.8

Type:

log Koc

Value:

< 1.25

Details on results (HPLC method):

- Retention times of reference substances used for calibration:
Formamide : 1.996
Acetanilide: 2.835 to 2.840
Phenol: 2.722 to 2.723
Isoproturon: 4.331 to 4.340
Triadimenol: 6.116 to 6.122
Linuron: 6.390 to 6.395
Naphthalene: 5.416 to 5.418
Endosulfan-diol: 8.327 to 8.341
Fenthion: 10.105 to 10.136
Phenanthrene: 10.939 to 10.944
Diclofop-methyl: 16.558 to 16.564
DDT: 36.670 to 37.424 to 36.670

- Details of fitted regression line (log k' vs. log Koc): A= -0.713
B = 0.366
- Graph of regression line attached
- Average retention data for test substance: 2.646 to 2.648

Adsorption and desorption constants:

No data

Recovery of test material:

No data

Concentration of test substance at end of adsorption equilibration period:

No data

Concentration of test substance at end of desorption equilibration period:

No data

Details on results (Batch equilibrium method):

No data

Statistics:

No data

Results of the calibration:

The capacity factors (k') and log Koc for the reference standards are shown in the following table:

Standard	Capacity factor (k’)	Log k’	Log Koc
Acetanilide	0.422	-0.375	1.25
Phenol	0.364	-0.439	1.32
Isoproturon	1.172	6.88*10^-^2	1.86
Triadimenol	2.065	0.315	2.40
Linuron	2.202	0.343	2.59
Naphthalene	1.714	0.234	2.75
Endosulfan-diol	3.175	0.502	3.02
Fenthion	4.070	0.610	3.31
Phenanthrene	4.481	0.651	4.09
Diclofop-methyl	7.296	0.863	4.20
DDT	17.559	1.24	5.63

Adsorption coefficient of sample:

The capacity factors (k') and log Koc value determined for the sample are shown in the following table:

Standard	Capacity factor (k’)	Log Koc	Mean log Koc	Adsorption coefficient
1	-0.487	< 1.25	<1.25	< 17.8
2	-0.487	< 1.25

In absence of any dissociating functional groups, non specific manipulation of the mobile phase pH was required. Therefore the determination was performed at an approximately neutral pH

Validity criteria fulfilled:

yes

Conclusions:

The adsorption coefficient (Koc) of the test item has been determined to be less than 17.8; log Koc <1.25.

Executive summary:

The determination was carried out using HPLC method, according to Method C19 Adsorption coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008, Method 121 of the OECD Guidelines for testing of Chemicals, 22 January 2001 and according to GLP. No deviation from the guideline was observed during the test.

The test used a high performance liquid chromatography system and a cyanopropyl reverse phase HPLC column containing lipophilic and polar moieties.

While passing through the column along within the mobile phase, the test item interacted with the stationary phase. As a result of partitioning between the mobile and stationary phase, the test item was retained. 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 was the case for organic matter in soil or sewage sludge matrices. This enables the relationship between the retention time on the column and the absorption coefficient on organic matter to been established.

The adsorption coefficient (Koc) of the test item has been determined to be less than 17.8; log Koc <1.25.

Description of key information

Experimental value for Koc : < 17.8
Experimental value for log Koc: < 1.25

Key value for chemical safety assessment

Koc at 20 °C:

17.8

Additional information

The determination was carried out using HPLC method, according to Method C19 Adsorption coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008, Method 121 of the OECD Guidelines for testing of Chemicals, 22 January 2001 and according to GLP. No deviation from the guideline was observed during the test.

In absence of any dissociating functional groups, non-specific manipulation of the mobile phase pH was required. Therefore the determination was performed at an approximately neutral pH.