Tetrakis(phenylmethyl)thioperoxydi(carbothioamide)

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:

27 Jul.-20 Sep. 2010

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))

Version / remarks:

Estimation of the adsorption coefficient on soil and on sewage sludge of Luvomaxx TBzTD using HPLC accord-ing to OECD 121 resp. EU C.19

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

GLP-Bescheinigung / Statement of GLP Compliance (according to to § 19 Abs.1 Chemikaliengesetz)

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Test temperature:

Column temperature was room temperature, 25 ± 1 °C.

Details on study design: HPLC method:

HPLC
Pump: Dionex P580 Pump
Injector: Rheodyne 8125)
Column: Reprosil-Pur CN Dr. Maisch, 4.6 mm i.D., 125 mm length, particle size 3 µm
Detector: Dionex, UVD 170S
Program: ChromeleonTM, Version 6.80
Column temperature was room temperature, 25 ± 1 °C.
Program LogKoc.pgm for measurement of the test item

Chemicals
All chemicals used in the test were “analytical grade” or otherwise proved suitable.
Water
Demineralised Water, HPLC-grade, giving no interferences with the detector signal.
Also used was deionised water.
Methanol
CH3OH, HPLC grade, giving no interferences with the detector signal.
Mobile Phase
A mixture of 55% methanol and 45% water, isocratic, was used. The mix was produced by the pump.
Test Item Solution (Lot 20100803)
A solution of the test item was prepared by weighing 13.7 mg Luvomaxx TBzTD into a tared 10 mL volumetric flask containing 10 ml eluent (Lot 28072008), resulting in a solution with a concentration of 1370 mg/l which was used for the measurements. pH was 5.5 (measured with pH indicator paper.)

Analytical monitoring:

yes

Details on sampling:

Pre-Test
A solution of the test item in eluent with a concentration of 1370 mg/L was prepared and injected in order to check detectability and to find an approximate range for log KOC.
The solution gave four peaks at 1.25, 4.46, 7.60 and 15.17 min., respectively.
Based on this result, a suitable mix of reference items was chosen (with DDT as sub-stance with the highest log KOC and a retention time of approx. 30.1 minutes). The undi-luted test item solution was used for the determination of the log KOC of the test item under the same conditions as in the pre-test.

Seven reference items with different retention times were used to produce a calibration curve, since retention time on cyanopropyl columns and KOC are correlated. The reference items were chosen on behalf of the retention time of the test item Luvomaxx TBzTD on the column.

First, a solution of the reference items was analysed three times with HPLC, then a solu-tion of the test item (three times) and finally three more times the solution with the refer-ences.

Details on matrix:

Not avalaible

Details on test conditions:

6.3.4 Test Item Solution (Lot 20100803)
A solution of the test item was prepared by weighing 13.7 mg Luvomaxx TBzTD into a tared 10 mL volumetric flask containing 10 ml eluent (Lot 28072008), resulting in a solution with a concentration of 1370 mg/l which was used for the measurements. pH was 5.5 (measured with pH indicator paper.)
Test System
HPLC
Pump: Dionex P580 Pump
Injector: Rheodyne 8125)
Column: Reprosil-Pur CN Dr. Maisch, 4.6 mm i.D., 125 mm length, particle size 3 µm
Detector: Dionex, UVD 170S
Program: ChromeleonTM, Version 6.80
Column temperature was room temperature, 25 ± 1 °C.
The following instruments and devices were used in the performance of the study:
• Adjustable Pipettes with one-way tips Rainin ® LAUS No. 16, 20, 30
• Analytical scale Mettler Toledo AB 184 SA
• Standard Laboratory Glassware

Sample No.:

#1

Duration:

1.254 min

Initial conc. measured:

1 370 other: mg/l A solution of the test item was prepared by weighing 13.7 mg Luvomaxx TBzTD into a tared 10 mL volumetric flask containing 10 ml eluent (Lot 28072008), resulting in a solution with a concentration of 1370 mg/l which was used for the measurements.

pH:

5.5

Sample No.:

#2

Duration:

4.46 min

Initial conc. measured:

1 370 other: A solution of the test item was prepared by weighing 13.7 mg Luvomaxx TBzTD into a tared 10 mL volumetric flask containing 10 ml eluent (Lot 28072008), resulting in a solution with a concentration of 1370 mg/l which was used for the measurements.

pH:

5.5

Sample No.:

#3

Duration:

7.6 min

Initial conc. measured:

1 370 other: A solution of the test item was prepared by weighing 13.7 mg Luvomaxx TBzTD into a tared 10 mL volumetric flask containing 10 ml eluent (Lot 28072008), resulting in a solution with a concentration of 1370 mg/l which was used for the measurements.

pH:

5.5

Sample No.:

#4

Duration:

15.17 min

Initial conc. measured:

1 370 other: A solution of the test item was prepared by weighing 13.7 mg Luvomaxx TBzTD into a tared 10 mL volumetric flask containing 10 ml eluent (Lot 28072008), resulting in a solution with a concentration of 1370 mg/l which was used for the measurements.

pH:

5.5

Computational methods:

Not avalaible/applicable

Type:

log Koc

Value:

2.422

Temp.:

25 °C

Remarks on result:

other: Log KOC + sd =2.422 ± 0.002

Type:

log Koc

Value:

3.422

Temp.:

25 °C

Remarks on result:

other: Log KOC + sd= 3.422 ± 0.002

Key result

Type:

log Koc

Value:

4.608

Temp.:

25 °C

Remarks on result:

other: Log KOC + sd= 4.608 ± 0.001

Details on results (HPLC method):

Calibration log k’ vs. log KOC
The calibration function was drawn up from the six measurements of the capacity factors of the reference items. By plotting the (known) log KOC values of the reference items against the mean log capacity factors and performing linear regression, a calibration func-tion was obtained.
Calculation of log KOC
With the calculated capacity factors for the test item, each log KOC from the three determi-nations was calculated.
Finally, mean and standard deviation of the log KOC were calculated.

Capacity Factor k’
The capacity factor k´ for every peak was calculated as follows:

K= tr-to/ to


with tr retention time
to dead time (retention time of sodium nitrate)

Adsorption and desorption constants:

not avalaible

Findings and Results

  Reference Items

 Measurement Data

The retention times which were found for the reference items are presented in the following table.

Table    Retention Times Reference Items

Compound	RT1	RT2	RT3	RT4	RT5	RT6
	min.	min.	min.	min.	min.	min.
Sodium nitrate	1.306	1.308	1.302	1.260	1.280	1.280
Phenole	3.032	3.037	3.036	3.032	3.030	3.032
Methylbenzoate	3.433	3.444	3.444	3.441	3.440	3.442
3,5-Dinitrobenzamide	3.623	3.622	3.624	3.623	3.621	3.621
Naphthaline	5.186	5.182	5.188	5.199	5.212	5.214
1,2,3-Trichlorbenzene	6.442	6.432	6.461	6.482	6.512	6.514
Pyrazophos	8.707	8.698	8.749	8.790	8.779	8.822
4,4’-DDT	29.560	29.617	29.383	30.085	30.966	31.081

 

 Calculated Values

The capacity factors k’ were calculated from the retention times using the equation stated in chapter 8.1. The values are given in the following table.

Table9.1-b      Mean Retention Times, Capacity Factors Reference Items

Compound	RT Mean	RT Stand. Dev.	RT Relative Stand. Dev.	k’
	min.	min.	%
Sodium nitrate	1.289	0.019	1.480	0.0000
Phenole	3.033	0.003	0.089	1.3525
Methylbenzoate	3.441	0.004	0.119	1.6686
3.5-Dinitrobenzamide	3.622	0.001	0.033	1.8095
Naphthaline	5.197	0.014	0.265	3.0306
1,2,3-Trichlorbenzene	6.474	0.035	0.538	4.0211
Pyrazophos	8.758	0.049	0.556	5.7923
4,4’-DDT	30.115	0.742	2.463	22.3573

 

  Log K_OC/ log k’

The log K_OCvalues of the reference items were taken from the guideline. The values for log k’ and log K_OCof the reference items are presented in the following table:

Table9.1-c      Log k’ and log K_OCof Reference Items

Compound	log k’	log KOC
Phenole	0.1311	1.32
Methylbenzoate	0.2223	1.80
3,5-Dinitrobenzamide	0.2575	2.31
Naphthaline	0.4815	2.75
1,2,3-Trichlorbenzene	0.6043	3.16
Pyrazophos	0.7628	3.65
4,4’-DDT	1.3494	5.63

 

    

 

 Correlation Results

Dead time is 1.289 ± 0.019 minutes, with a RSD of 1.48%.

 

The RSD of the retention times of the reference items lay all below1 % except for Sodium nitrate and DDT, which have RSDs of retention times of 1.48 and 2.46%, respectively.

 

Equation of the regression:

log k’ = 0.2934 * log K_OC– 0.32
with a coefficient of determination r²= 0.986.

Validity criteria fulfilled:

yes

Remarks:

No observations were made which might give doubts concerning the validity of the study outcome.

Conclusions:

Although area is not necessarily correlated to absolute concentration if a UV detector is used, it is believed that the test item of Luvomaxx TBzTD consists mainly of the fourth peak, indicating that the log Koc should be regarded as 4.608.
No observations were made which might give doubts concerning the validity of the study outcome.

Executive summary:

The adsorption/desorption potential of TBzTD was determined according to an OECD 121 testing.

Based on the results, the log Koc of TBzTD is 4.6.

Key value for chemical safety assessment

Koc at 20 °C:

40 551

Additional information

The adsorption/desorption potential of TBzTD was determined according to an OECD 121 testing.

Based on the results, the log Koc of TBzTD is 4.6.