Reactionmass of octan-2-yl prop-2-enoate and octan-3-yl prop-2-enoate and octan-4-yl prop-2-enoate

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:

March 30, 2020 to September 18, 2020

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

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

Specific details on test material used for the study:

Source and lot/batch No.of test material: 3M FMRD, S352546
- Expiration date of the lot/batch: August 12, 2021
- Purity test date:August 12, 2019
- Storage condisition: 15 -25 °C

Radiolabelling:

no

Details on study design: HPLC method:

EQUIPMENT
- Type: HPLC WATERS 2695
- Column: ECLIPSE XDB-CN (4.6 x 250 mm; 5 µm)
- Oven Temperature: 30 °C
- Mobile phase: 60/40 (v/v) methanol/Milli-Q water
- Flow rate: 1.2 mL/min;
- Injection volume: 10 µl
- Detection system: Refractive index detector, wavelength 210 nm

DETERMINATION OF DEAD TIME T0 (retention time of the unretained component): A solution of Sodium nitrate (CAS# 7631-99-4) at 10 mg/L is used to determine dead time. The Sodium nitrate solution was injected three times at the HPLC condition, and the average value of three retention times was considered to be the dead time T0. Under the test condition, the retention times were 1.784 min, 1.798 min and 1.802 min. Mean retention time was 1.795 min.

REFERENCE SUBSTANCES: Six reference compounds were used in this test: Phenol, Carbendazim, Naphtalene, Triazophos, Phenantrene, and 2,4-DDT. Reference substances solutions were prepared at concentrations between 10 and 100 mg/l in mobile phase.

Injection sequence: 1) The reference substances were inject individually for the first time and record the retention time (tR1); 2) The test substance was injected one time and record the retention time (tR); 3) The reference substances were injected individually for the second time and retention time (tR2) recorded. The average value of tR1 and tR2 is calculated to be the tR of reference substances, which was employed in the k’ calculation. The injection sequence was repeated, and the average value of these two injection sequences was calculated as the definite result for the test item (Table 2).

REPETITIONS
- Number of determinations: 2

EVALUATION
- Calculation of capacity factors k': The capacity factor (k') is calculated from the retention time of the test substance (Tr) and the unretained component (T0): k' = (Tr- T0)/T0
- Calculation of retention times: Average retention time of the two injection sequences
- Determination of the log Koc value: Linear regression according to calibration curve of the log k of the reference substances as function of log Koc
log k' = a log Koc + b
a = slope derived from linear regression of reference compound;
b = intercept derived from linear regression of reference compound.

Analytical monitoring:

yes

Details on sampling:

A stability test in CaCl2 solution was performed. 1 mL stock solution of 1008.4 mg/L of MTDID 44428 was added into 1000 mL 0.01 mol/L CaCl2 to achieve a nominal concentration of 1 mg/L. The samples were stirred for 30 minutes. The concentration was measured by taking sample from the upper and middle layer of the test vessel on the 0,4,6 and 24 hours. Duplicate samples were prepared for each time point. 5.0 mL of the sample solution was transferred and added into 0.5 mL of 0.1 mol/L EDTA followed by vortex for 5 seconds. Then 5.0 mL of CH2Cl2 was added and vortexed for 1 minutes, the solution stayed overnight for equilibrium. The Ch2Cl2 layer was filtered by 0.22 µm membrane and diluted 10-fold prior to analysis by GC/MS/MS.

A Tier 1-preliminary batch equilibrium test was conducted based on OECD Guidelines No.106 “Adsorption/desorption Using a Batch Equilibrium Method (2000).

Two preliminary tests were performed with sterilized soils and unsterilized soils, respectively. The sterilized soils were prepared under 121 °C for 30 min. Five soil types were used with a solution/soil ratio of 5:1. Five g of each soil were pre-equilibrated with 25.0 mL 0.01 mol/L CaCl2 solution was agitated at 160 rpm for at least 12h at 20-25 °C. A stock solution of 1008.4 mg/L MTDID 44428 was prepared by adding 0.05042 g test item in 50.0 mL of acetonitrile. After pre-equilibrium, 24.8 µL stock solution of 1008.4 mg/L MTDID 44428 was added into the aqueous phase of each test system to achieve a nominal concentration of 1 mg/L MTDID 44428. Agitation was then continued for another 24 hours to reach adsorption equilibrium. The aqueous phase was then separated from the soil phase by centrifugation at 5000 rpm for 5 min. One vessel were measured for the concentration of MTDID 44428 in aqueous phase (supernates) and soil after 4, 6, and 24 hours. The concentration at time 0 was not measured.

For aqueous phase measurement: The volume of aqueous phase recorded. 5.0 mL of the supernatant was transferred and added into 0.5mL of 0.1 mol/L EDTA followed by vortex for about 5 seconds. Then 5.0 mL CH2C12 was added to extract test item by vortex for about 1 min. After extracting, the solution was stayed overnight for equilibrium. The CH2Cl2 layers were diluted and filtered by 0.22 µm membrane, prior to analysis by GC/MS/MS.

For soil phase measurement: 0.3mL of 0.1 mol/L EDTA was added to the remaining soil and allow to settle for about 1 hour. Acetonitrile was added to obtain total volume of 20.0 mL, followed by shaking at 180 rpm for 30 min. The acetonitrile extracts were filtered by 0.22 µm membrane, prior to analysis by GC/MS/MS.

Matrix no.:

#1

Matrix type:

other: Loess soil from Yinchuan, Ningxia autonomous region, P.R.China

% Org. carbon:

1.47

pH:

7.57

Matrix no.:

#2

Matrix type:

other: Aquic brown soil from Shenyang, Liaoning province, P. R.China

% Org. carbon:

1.19

pH:

5.47

Matrix no.:

#3

Matrix type:

other: Red Soil from Qidong, Hunan province, P. R. China

% Org. carbon:

1.13

pH:

4.93

Matrix no.:

#4

Matrix type:

other: Black Soil from Suihua, Heilongjiang province, P.R.China

% Org. carbon:

1.16

pH:

6.54

Matrix no.:

#5

Matrix type:

other: Moisture soil from Wuqing, Tianjin, P.R.China municipality

% Org. carbon:

1.37

pH:

7.25

Key result

Type:

log Koc

Value:

2.8 dimensionless

Temp.:

30 °C

Details on results (HPLC method):

Retention times of reference substances used for calibration: 2.815 - 9.928 minutes
- Details of fitted regression line (log k' vs. log Koc):
1st sequence: log Koc = 4.4147 x log k’+2.5257 (R2=0.9256)
2nd sequence: log Koc = 4.4156 x log k’+2.5337 (R2=0.9250)

- Average retention data for test substance: In the HPLC condition, there was one peak for the test substance. Retention time was 3.865 minutes for the 1st sequence, and 3.858 minutes for the 2nd sequence.

Details on results (Batch equilibrium method):

For the stability test: the measured concentration ar 24 hours was 58% for 4-octyl acrylate isomer (peak 1), 57% for 3-octyl acrylate isomer (peak 2), and 56% for 2-octyl acrylate isomer (peak 3), compare to the concentration at 0 hour. The concentration could not be maintained at 80-120% of the initial concentration.

For the tier 1 preliminary test:
Duplicate control samples were prepared with 0.01 mol/L CaCl2 solution with the test item of 1 mg/L but without soil (C0 control unit). After 24 hours, the mass balance was in the range of 0.2% - 4.4%, indicate that MTDID 44428 was not stable in the CaCl2 solution.

Mass balance in the sterilized soil/solution system were measured at 4- and 6-hours incubation. Mass balances range from 47.1 -151.7% for 4-octyl acrylate isomer (peak 1), 40.7 -105.7% for 3-octyl acrylate isomer (peak 2), and 36.4 – 93.2% for 2-octyl acrylate isomer (peak 3). The % adsorption range from 97.5 - 99.4% for 4-octyl acrylate isomer (peak 1), 96.7 - 99.6% for 3-octyl acrylate isomer (peak 2), and 95.1 – 99.7% for 2-octyl acrylate isomer (peak 3).

Mass balance in the unsterilized soil/solution system were measured at 4-, 6- and 24-hours incubation. Mass balances range from 0.5 – 10.2% for 4-octyl acrylate isomer (peak 1), 0.7 -11.1% for 3-octyl acrylate isomer (peak 2), and 0.5 – 12.9% for 2-octyl acrylate isomer (peak 3). The % adsorption was not reported.

Due to the lack of recovery in the soil free control unit (0.01 mol/L CaCl2 solution), the batch equilibrium method was not suitable for the test item MTDID 44428. Therefore, the HPLC method was subsequently employed to estimate the log Koc of test item.

Table 2. Log Koc determination for MTDID 44428 using HPLC method

Substances	tR1 (min)	tR2 (min)	Mean tR (min)	k’	log k’	log Koc
Sodium Nitrate			1.795
First sequence
Phenol	2.820	2.817	2.819	0.570	-0.244	1.32
Carbendazim	3.012	3.001	3.007	0.675	-0.171	2.35
Naphtalene	3.944	3.934	3.939	1.195	0.077	2.75
Triazophos	4.366	4.352	4.359	1.429	0.155	2.55
Phenantrene	5.625	5.608	5.617	2.130	0.328	4.09
p,p’-DDT	9.928	9.864	9.896	4.514	0.655	5.63
MTDID 44428	3.865			1.154	0.062	2.80
Second sequence
Phenol	2.817	2.815	2.816	0.569	-0.245	1.32
Carbendazim	3.001	2.998	3.000	0.671	-0.173	2.35
Naphtalene	3.934	9.926	3.930	1.190	0.075	2.75
Triazophos	4.352	4.347	4.350	1.424	0.153	2.55
Phenantrene	5.608	5.596	5.602	2.121	0.327	4.09
p,p’-DDT	9.864	9.843	9.854	4.490	0.652	5.63
MTDID 44428	3.858			1.150	0.061	2.80

 

Conclusions:

The adsorption coefficient (log Koc) of MTDID 44428 was determined to be 2.80 at 30°C according to OECD 121 "Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using HPLC".

Executive summary:

A Tier 1 preliminary batch equilibrium method was performed according to OECD Guidelines No.106 “Adsorption/desorption Using a Batch Equilibrium Method (2000). During the study, it was demonstrated that the test item was not stable in the calcium chloride solution. Two replicates control samples containing 0.01 mol/L CaCl2 solution with a starting nominal concentration of MTDID 44428 at 1 mg/L and no soil were prepared. After 24 hours,the mass balance was in the range of 0.2% - 4.4%.The batch equilibrium method was considered not suitable for the test item, the HPLC method was subsequently employed to estimate the log Koc of test item.

Log Koc value of MTDID 44428 was determined according to OECD 121 "Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using HPLC". Six reference substances including Phenol, Carbendazim, Naphtalene, Triazophos, Phenantrene, and 2,4-DDT were employed. One peak was found for MTDID 44428. Under the analytical conditions used, the test substance had a log Koc value of 2.80. The study was conducted according to test guidelines and under GLP compliance. The reference substances are approved for use in the method but bear little or no structural similarity to the test substance. Therefore, this study is considered as reliable with restrictions and a key study.

Description of key information

The adsorption coefficient (log Koc) of MTDID 44428 was determined to be 2.80 at 30°C according to OECD 121 "Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using HPLC".

Key value for chemical safety assessment

Koc at 20 °C:

630

Additional information

A Tier 1 preliminary batch equilibrium method was performed according to OECD Guidelines No.106 “Adsorption/desorption Using a Batch Equilibrium Method (2000). During the study, it was demonstrated that the test item was not stable in the calcium chloride solution, with mass balance range from 0.2% - 4.4% after 24 hours. Therefore, the batch equilibrium method was considered not suitable for the test item.

Log Koc value of MTDID 44428 was determined according to OECD 121 "Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using HPLC". Six reference substances with experimentally literature log Koc values of 1.32 – 5.63 were used. Under the analytical conditions used, the test substance had a log Koc value of 2.80 at 30 °C. This study was conducted according to test guidelines and under GLP compliance. The reference substances are approved for use in the method but bear little or no structural similarity to the test substance. Therefore, this study is considered as reliable with restrictions and a key study. This study is pertinent to the fate of MTDID 44428 and may be used for Risk Assessment.