O,O,O-triphenyl phosphorothioate

Adsorption / desorption

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

adsorption / desorption: screening

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

In Article 13 of Regulation (EC) No 1907/2006, it is laid down that information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI (of the same Regulation) are met. Furthermore according to Article 25 of the same Regulation testing on vertebrate animals shall be undertaken only as a last resort.

According to Annex XI of Regulation (EC) No 1907/2006 (Q)SAR results can be used if (1) the scientific validity of the (Q)SAR model has been established, (2) the substance falls within the applicability domain of the (Q)SAR model, (3) the results are adequate for the purpose of classification and labeling and/or risk assessment and (4) adequate and reliable documentation of the applied method is provided.

For the assessment of the substance (Q)SAR results were used for adsorption. The criteria listed in Annex XI of Regulation (EC) No 1907/2006 are considered to be adequately fulfilled and therefore the endpoint(s) sufficiently covered and suitable for risk assessment.

Therefore, further experimental studies on adsorption/desorption are not provided.

Principles of method if other than guideline:

KOCWIN (v2.00): estimation using first-order Molecular Connectivity Index (MCI)
KOCWIN (v.2.00): estimation using estimated or experimentally derived logKow

Key result

Type:

Koc

Value:

198 000 L/kg

Temp.:

25 °C

Remarks on result:

other:

Remarks:

MCI method. The substance is within the applicability domain of the model.

Key result

Type:

Koc

Value:

3 972 L/kg

Temp.:

25 °C

Remarks on result:

other:

Remarks:

estimation from logKow. The substance is within the applicability domain of the model.

Koc Estimate from MCI:

---------------------

First Order Molecular Connectivity Index ........... : 11.235

Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 6.4566

Fragment Correction(s):

1  OrganoPhosphorus [P=S] ............... : -1.1599

Corrected Log Koc .................................. : 5.2966

 

Estimated Koc: 1.98e+005 L/kg  <===========

 

Koc Estimate from Log Kow:

-------------------------

Log Kow (User entered  ) ......................... : 5.00

Non-Corrected Log Koc (0.55313 logKow + 0.9251) .... : 3.6907

Fragment Correction(s):

1  OrganoPhosphorus [P=S] ............... : -0.0917

Corrected Log Koc .................................. : 3.5990

 

Estimated Koc: 3972 L/kg  <===========

Validity criteria fulfilled:

yes

Reference 2

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From Oct. 8, 1997 to Nov. 15, 1997

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 106 (Adsorption - Desorption Using a Batch Equilibrium Method)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Radiolabelling:

no

Test temperature:

40°C

Details on study design: HPLC method:

HPLC pump: M 480, from Gynkotek, München, BRD
Degasser: DG-1300, from Gynkotek, München, BRD
Autosampler: Gina M 160, from Gynkotek, München, BRD
UV detector: UVD 160-2, from Gynkotek, München, BRD
Thermostat: MGW Lauda RM 20, from MGW, Lauda-Königshofen, BRD
Column thermostat: Cosytherm, from Labor Technik Barkey, Bielefeld, BRD
Column temperature: 40°C
Chromatographic data system: PC AT386 with GYNKOSOFT Version 5.50, from Gynkotek, München, BRD
Column dimensions: 250x4.6 mm
Stationary phase: cyanopropyl (5 μm, Zorbax CN), from VDS Optilab, Berlin, BRD
Injection volume: variable between 10 μl and 200 μl
Mobile phase: methanol: 0.01 mol/l citrate buffer pH 6.0 = 70 : 30 / v:v
Flow rate: 1.0 ml/min
Solutes for dissolving test and reference substances: methanol.

DETERMINATION OF DEAD TIME
A formamide stock solution was prepared by dissolving formamide in methanol. An aliquot of this solution was chromatographed under standard chromatographic conditions and the retention time of formamide was determined.

REFERENCE SUBSTANCES
1,2,3-Trichlorobenzene
Fenthion
Acenaphthene
Phenanthrene
Hexachlorobenzene
Pyrene
4,4'-DDT
REFERENCE COMPONENTS FOR THE COMPONENTS OF THE TEST SUBSTANCE:
For following references 6 reference components which are mono constituents or which contain of several constituents were used:
-2-tert.butylphenyl-diphenylthiophosphate
-4-tert.butylphenyl-diphenylthiophosphate
-Di-(2-tert.butylphenyl)-phenylthiophosphate
-2,4-tert.butylphenyl-diphenylthiophosphate
-Di-(4-tert.butylphenyl)-phenylthiophosphate
-Tri-(2-tert.butylphenyl)-thiophosphate
-Tri-(4-tert.butylphenyl)-thiophosphate
-Di-(2,4-tert.butylphenyl)-phenylthiophosphate
-Tri-(2,4-tert.butylphenyl)-thiophosphate

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column:
TKA 40116 50.0 mg/l in methanol 200 μl injected
different tertiary butylated phenyl derivatives:
(reference component 1) 44.5 mg/l in methanol 200 μl injected
(reference component 2) 45.5 mg/l in methanol 200 μl injected
(reference component 3) 48.0 mg/l in methanol 200 μl injected
(reference component 4) 52.0 mg/l in methanol 200 μl injected
(reference component 5) 57.5 mg/l in methanol 200 μl injected
(reference component 6) triphenylthiophosphate 48.0 mg/l in methanol 200 μl injected


- Quantity of reference substances:
1,2,3-Trichlorobenzene 27.7 mg/l in methanol 25 μl injected
Fenthion 11.6 mg/l in methanol 50 μl injected
Acenaphthene 9.9 mg/l in methanol 50 μl injected
Phenanthrene 25.3 mg/l in methanol 25 μl injected
Hexachlorobenzene 12.5 mg/l in methanol 50 μl injected
Pyrene 25.1 mg/l in methanol 25 μl injected
4,4'-DDT 10.9 mg/l in methanol 50 μl injected

- Intervals of calibration:
The calibration was performed at regular intervals in duplicate at least once a working day.

REPETITIONS
- Number of determinations: one


EVALUATION
- Calculation of capacity factors k':
k' = ( tR - t0 ) / t0
tR = retention time of reference substance or component of the test substance
t0 = column dead time (retention time of formamide)

- Determination of the log Koc value: Linear regression analysis

Analytical monitoring:

no

Key result

Type:

log Koc

Value:

5.31

Remarks on result:

other: main component CAS 597-82-0

Type:

log Koc

Value:

> 5.63

Remarks on result:

other: Butylated derivates of the main component

Details on results (HPLC method):

- Retention times of reference substances used for calibration:
1,2,3-Trichlorobenzene 4.78 min
Fenthion 5.47 min
Acenaphthene 5.25 min
Phenanthrene 6.01 min
Hexachlorobenzene 7.05 min
Pyrene 7.26 min
4,4'-DDT 8.45 min

- Details of fitted regression line (log k' vs. log Koc):
log Koc = 5.236 x log k' + 4.008; correlation coefficient = 0.976

- Graph of regression line attached

- Average retention data for test substance:
( 1) 8.14 min Triphenylthiophosphate
different tertiary butylated phenyl derivatives:
(2) 10.28 min
(3) 12.99 min
(4) 16.27 min
(5) 18.73 min
(6) 26.21 min
(7) 28.74 min
(8) 60.0 = n. d.

(1) detected in reference component 6 and in the test substance
(2) detected in reference component 1 and in the test substance
(3) detected in reference component 2 and in the test substance
(4) detected in reference component 1
(5) detected in reference component 3
(6) detected in reference component 2
(7) detected in reference component 1 and in reference component 4
(8) substance was not detectable because it was not eluted from the HPLC column with the eluant used

log Koc of the butylated derivates of the main component is much higher than 5.6 (which is the log KOC of 4,4'-DDT)

A suitable set of reference substances with adsorption coefficients (log KOC), which had been determined using the OECD guideline 106, and the test substance and the reference components of the test substance were chromatographed under standard chromatographic conditions and their retention times (t,,) were determined. Using the retention times and the column dead time (t0), which was determined by means of formamide, the corresponding capacity factors (k') were calculated. The log k' of the reference substances and their log KOC- values were used to construct a calibration plot of log k' versus log KOC. The adsorptioncoefficient

(log KOC) of the main component of the test substance was calculated using its log k' and the fitted regression line.

The adsorption-coefficients (log KOC) of the butylated derivatives of the main component, however, could not be correctly determined by means of the normal evaluation procedure, because the retention time (tR) and the corresponding capacity factor (k') of the butylated derivatives of the main component are outside the calibration range.

Furthermore it is impossible to extend the calibration range to higher log KOC-values, because 4,4'-DDT is the substance with the highest log KOC-value, which had been determined by means of the OECD guideline 106. It is essential for the application of the calibration procedure in the HPLC-screening method to have a log K^^-value, which had been determined by means of the

OECD guideline 106. That means there will be no other set of reference substances which will allow for more than an estimation of the adsorption coefficient of the butylated derivatives of the main component of the test substance.

Validity criteria fulfilled:

yes

Description of key information

Adsorption of O,O,O-triphenyl phosphorothioate to the solid phase is expected.

Key value for chemical safety assessment

Koc at 20 °C:

199 526

Additional information

The adsorption coefficient was determined in a HPLC screening study according to OECD 106 using O,O,O-triphenyl phosphorothioate in a lower purity (purity > 25%)(Fraunhofer IME, 1997). The KOC of the individual components were investigated and for CAS 597-82-0 determined to be 199526 (log KOC = 5.3). This result is supported by EPISUITE estimations resulting in log KOCs of 5.3 (MCI method) and 3.6 (estimated from measured log Kow of 5) (BASF SE, 2011). Based on the consensus of MCI methodology and experimental data the log KOC of 5.3 is used for further assessments.