1,3,5-tris(2,3-dibromopropyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione

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:

26 April 2022 to 28 April 2022

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))

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Radiolabelling:

no

Test temperature:

25 ± 1°C

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: Agilent 1260 Series High Performance Liquid Chromatograph (HPLC) equipped with DAD, auto sampler and PC based data system, Quaternary pump.
- Analytical column: Inertsil CN, 250 mm X 4.6 mm i.d., 5 µm particle size, surface area 450 m2/g and pore size 100 Å
- Detection system: DAD

MOBILE PHASES
- Type: Milli-Q Water : Acetonitrile (45 : 55% v/v)
- pH: 7.11

DETERMINATION OF DEAD TIME
The dead time was determined by means of retention time of inert substance (i.e., Formamide), which was not retained on the column.

REFERENCE SUBSTANCES
1. R.S. Name : Acetanilide
Purity : 99 %

2. R.S. Name : Methyl Benzoate
Purity : 99%

3. R.S. Name : Benzophenone
Purity : 99 %

4. R.S. Name : Benzyl benzoate
Purity : 99.0 %

5. R.S. Name : Phenanthrene
Purity : 98 %

6. R.S. Name : Deltamethrin
Purity : 99.62 %

DETERMINATION OF RETENTION TIMES
Details are given in the attached full study report under "5.3.1 Preparation of Inert Substance, Reference Substances and Test Item Solutions".

REPETITIONS
Inert substance solution (Formamide) was injected in duplicate to determine the dead time based on its retention time.
All the selected reference substance solutions were analyzed in duplicate separately and the test item solution was analyzed in triplicate to determine the retention time.
The calibration mixture was injected before and after the sample injections to check the instrument performance.

EVALUATION
- Calculation of capacity factors k': The k′ value for all reference substances and test item was calculated from the dead time t0 and the respective measured retention times tr according to the following equation: k'= tr-t0/t0
- Determination of the log Koc value: The adsorption coefficient (KOC) was deduced from the capacity factor (k’) using a calibration plot of log k′ versus log KOC of the reference substances. From the calibration line, values of
intercept (a), slope (b) and correlation coefficient (r) were obtained. By substituting the a and b values and the log k’ values of the test item in the equation log KOC = a + b log k’, the logarithm of the adsorption coefficient of the test
item was determined.

Key result

Type:

log Koc

Value:

5.44

Temp.:

25 °C

Key result

Type:

Koc

Value:

275 422.87

Temp.:

25 °C

Details on results (HPLC method):

- Retention times of reference substances used for calibration: Refer to tables 1 and 2 in section "Any other information on results incl. tables".
- Details of fitted regression line (log k' vs. log Koc): The linear regression of log k′ values and log KOC of the calibration standards gave a correlation coefficient of 0.9511 and the following equation describing the regression line:
Log KOC = 4.0994 + 6.9931 (log k′)
- Graph of regression line: refer to the attached full study report (Figures 10 and 11).
- Average retention data for test substance: 7.047 minutes in the determination test, 6.987 minutes in the repeatability test.

The retention time, capacity factor (k'), log k' and log Koc of the six reference substances and of the test item AP 729 obtained in the first determination and during the repeatability test are presented in Tables 1 and 2, respectively. 

Table 1 - Results of Adsorption Coefficient

Reference substance / Chemical	Replication	Retention time (min.)	Mean Retention time (min.)	Capacity factor (k’)	log k’	# log Koc
Formamide (Inert substance)	R1	2.758	2.758	-	-	-
	R2	2.757
Acetanilide	R1	3.628	3.628	0.3154460	-0.5011	1.25
	R2	3.627
Methyl benzoate	R1	4.160	4.161	0.5087020	-0.2935	1.80
	R2	4.162
Benzophenone	R1	4.815	4.815	0.7458303	-0.1274	2.63
	R2	4.814
Benzyl benzoate	R1	5.246	5.246	0.9021030	-0.0447	3.80
	R2	5.246
Phenanthrene	R1	6.214	6.219	1.2548949	0.0986	4.09
	R2	6.223
Deltamethrin	R1	8.182	8.183	1.9670051	0.2938	7.01
	R2	8.184
AP 729	R1	7.047	7.047	1.5551124	0.1918	5.44
	R2	7.044
	R3	7.049

 

Table 2 - Results of Adsorption Coefficient (Repeatability)

Reference substance / Chemical	Replication	Retention time (min.)	Mean Retention time (min.)	Capacity factor (k’)	log k’	# log Koc
Formamide (Inert substance)	R1	2.758	2.7585	-	-	-
	R2	2.759
Acetanilide	R1	3.626	3.6250	0.3141	-0.5029	1.25
	R2	3.624
Methyl benzoate	R1	4.155	4.1550	0.5063	-0.2956	1.80
	R2	4.155
Benzophenone	R1	4.799	4.7970	0.739	-0.1314	2.63
	R2	4.795
Benzyl benzoate	R1	5.225	5.2270	0.8949	-0.0482	3.80
	R2	5.229
Phenanthrene	R1	6.194	6.1945	1.2456	0.0954	4.09
	R2	6.195
Deltamethrin	R1	8.150	8.1485	1.954	0.2909	7.01
	R2	8.147
AP 729	R1	6.986	6.9873	1.5330	0.1855	5.42
	R2	6.981
	R3	6.995

Note: the log K_oc values of the reference standards are obtained in batch equilibrium experiments (published data, reference OECD 121, Table 3). 

Validity criteria fulfilled:

yes

Conclusions:

The KOC value for AP 729 was determined to be 275422.87 (log KOC = 5.44).

Executive summary:

The present study was conducted according to OECD Guideline 121 to determine the adsorption coefficient K_oc using high performance liquid chromatography (HPLC).

A cyanopropyl column consisting of stationary phase with both non-polar and polar sites was used at controlled temperature (25 ± 1°C): the interaction of the non-polar and polar sites on the column with polar and non-polar groups on the molecule is similar to how the molecule would act in the presence of organic matter in soil or sewage sludge. Due to this similarity, it is possible to relate the retention time on the selected column with the adsorption coefficient on organic matter.

The determination of the dead time by inert substance (Formamide) provided a dead time value (t₀) of 2.758 min. The details of the retention time, capacity factor (k′), log k′ and log K_oc of the six reference substances of both first determination and repeatability tests are provided in Table 1 and Table 2 in section "Any other information on results incl. tables".

The linear regression of reported log K_oc values and measured capacity factors log k′ of the calibration standards gave a correlation coefficient of 0.9511 and an equation describing the regression line (log KOC = a + b log k’). 
The obtained correlation coefficient was in acceptable range, i.e., above 0.95.

Using the regression equation obtained, the log K_oc value of the test item AP 729 was calculated allowing the adsorption coefficient to be determined. The obtained K_oc of the test item AP 729 was 275422.87 and the respective log K_oc value was 5.44.

Similarly, the log K_oc value of the test item AP 729 was calculated from the results obtained from the repeatability test and alog K_oc value of 5.42 was obtained and was within 0.25 log units as compared to the first determination mentioned above.

Description of key information

A study was conducted according to OECD Guideline 121 to determine the adsorption coefficient K_oc using high performance liquid chromatography (HPLC).

A cyanopropyl column consisting of stationary phase with both non-polar and polar sites was used at controlled temperature (25 ± 1°C).
The linear regression of reported log K_oc values and measured capacity factors log k′ of the calibration standards gave a correlation coefficient of 0.9511 and an equation describing the regression line (log KOC = a + b log k’). 
Using the regression equation obtained, the log K_oc value of the test item AP 729 was calculated: the obtained K_oc of the test item AP 729 was 275422.87 and the respective log K_oc value was 5.44.

Key value for chemical safety assessment

Koc at 20 °C:

275 422.87