2,2-bis[(allyloxy)methyl]butyl (3-{[({2,2-bis[(allyloxy)methyl]butoxy}carbonyl)amino]methyl}-3,5,5-trimethylcyclohexyl)carbamate

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:

16 July 2009 to 27 September 2009

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: "The Guidelines for the testing of chemicals" State Environmental Protection Administration (SEPA) of China, No.106

Deviations:

no

GLP compliance:

yes

Type of method:

HPLC estimation method

Media:

soil

Radiolabelling:

no

Test temperature:

22.5°C

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: Agilent triple quad 6410 LC/MS, USA
Column: ZORBAX SB C18 30 mm x 2.1 mm x 3.5 µm

-Conditions:
Current velocity: 0.4 mL/min
Column temperature: 40°C
Run time: 2 min
Testing volume: 1 µL
Mobile phase A: 0.1% formic acid in water (20%)
Mobile phase B: Acetonitrile (80%)

ESI(+) ionisation mode
Dry gas: N2; Gas flow: 11 L/min; Gas temperature: 350°C
Capillary: 4000 V

CALIBRATION CURVE
0.1 g (0.0001 g) of the test material was added into a 100 mL measuring flask, 80 mL acetonitrile was added to resolve, then it was diluted to the degree. The stock solution was diluted to give standard solutions 10, 8, 6, 4, 2, 1 and 0.1 ng/mL. The plot working curve was y = 20412x + 3878.4 R2 = 0.999.

LOD
100 pg/mL of test material treatment fluid is prepared for the LOD test and run 6 times. The LOD of the method can be calculated by SIN, LOD = 2.4 x10^-8 g/L.

PREPARATION OF TEST SOLUTION
The test material was weighed into the glass container, CaCl2 solution was added and it was oscillated for 48 h at 30°C. The test solution was then left to reach room temperature and the supernatant was filtered through a 0.45 µm pore size membrane filter. As the test solution was almost insoluble in CaCI2 solution, this study could not applicable with the standardised guideline.

SOILS
Standard soil samples were supplied by China Environmental Monitoring Station. Three types of soil with different characteristics in the cation changing, clay content, organic carbon and pH were used. They were ESS-1 (collected from Dehui Changchun), ESS-2 (collected from Jin Town Dalian) and ESS-3 (collected from Jinwanzi Changsha).

CONDITIONS
-Temperature: 22.5°C
-Relative humidity: 55%

METHODS
-Screening experiment
Adsorption test: The standard soil samples were weighed and mixed with CaCl2 solution (twice the soil weight) and gently oscillated for 24 hours before testing. The test solution was added (one/fifth of the soil weight) and oscillated for 24 hours. Each soil group set up a parallel and a blank sample, and set a blank without soil. The concentration of the test material was analysed by Agilent HPLC 1100. If the test material was non-adsorbing or showed weak adsorption (the adsorption rates less than 25%), then no desorption test was conducted. If the adsorption rates were more than 25%, a desorption test was conducted.

Desorption test: A certain volume of CaCl2 solution was added into the soils which were left from the adsorption test, and oscillated for 16 hours, then tested. The same volume of CaCl2 solution was added again and the process repeated. If the test material was easily desorbed, there was no need for further testing. If not, a further test was conducted to calculate the mass balance and adsorption isotherms.

-Further test
Adsorption test: The adsorption test was conducted with an appropriate concentration of test material solution to confirm equilibrium conditions (equilibrium time and equilibrium concentration), then the adsorption isotherms of the test material were calculated by conducting an adsorption test with 4 test solutions of different concentrations (approx. 0.04, 0.2, 1 and 5 mg/L) .

Mass balance: After adsorption equilibrium is reached, one concentration group is tested. Using a solvent in which the test material could be easily dissolved, the solution was extracted three times and the extraction solution tested. Methanol was used as an extraction agent in this experiment.

DATA PROCESSING
-Adsorption rate (A %) = 100 (G-CeV0)/G = 100X/G
-Desorption rate (D %) = 100 [(C1+C2)V ¿ (V0-V)Ce]/X

Where:
A = Adsorption rate at adsorption equilibrium (%)
D = Desorption rate (%)
G = The mass of control sample with only the test material in deionised water (g)
Ce = Concentration of the material in the aqueous phase after adsorption (mg/L)
V0 = Initial volume of test solution (mL)
C1 = The concentration of test material after the first desorption test (mg/L)
C2 = The concentration of test material after the second desorption test (mg/L)
V = Volume of the test solution after the desorption test (mL)

-Adsorption coefficient (K¿ and K¿oc)
K¿ = Cs/Ce
Cs = X/m
K¿oc = K¿ / organic carbon x 100%
Ce = C¿e + (C0 ¿ C1)

Where:
m = Mass of soil (g)
X = Mass of the absorbed material (µg)
K' = Adsorption coefficient
K'oc = Coefficient represents a single value which characterizes the partitioning mainly of non-polar organic chemicals between the organic carbon in the soil and water.
Cs = Concentration of the test material in soil after adsorption (µg/g)
Ce = Concentration of the test material in the aqueous phase after adsorption (mg/L)
C'e = Concentration of the test material in the aqueous phase (mg/L)

-Adsorption isotherms: lg (X/m) and lg(Ce) are plotted. If the plots are linear, the values of lgK and 1/n in the Freundlich adsorption isotherms equation X/m = KCe/n were calculated by regression analysis using the equation lg(X/m)= lgK + (1/n) lg(Ce) and calculated Koc, of the test.

-Mass Balance: The content of test material in solution at the beginning of the test, in the aqueous phase and in organic solvent were calculated, to check if the percentage of test material which can be analytically recovered after an adsorption test was close to the nominal amount of test material at the beginning of the test.

Key result

Type:

log Koc

Value:

5.51

Remarks on result:

other: Estimated using prediction software

Remarks:

MCI method

Key result

Type:

log Koc

Value:

4.499

Remarks on result:

other: Estimated using prediction software

Remarks:

Kow method

Details on results (HPLC method):

-In the preliminary test and the screening test, the test material (at 25°C) in its CaCl2 solution was not detected and the LOD of analysis method is 2.4 x 10^-8/L. The solubility of test material in the CaCl2 solution is therefore less than 2.4 x 10^-8 g/L. This study could therefore not be performed in line with "The Guidelines for the testing of chemicals" State Environmental Protection Administration (SEPA) of China, No. 106, 'Adsorption/Desorption'.

-Therefore, the organic carbon adsorption coefficient of the reaction products was estimated using specialist chemical prediction software EPI-Suite v.4.0 Environmental Protection Agency, which could successfully predict the absorption coefficients of the reference substances. The predicted results were:

Koc: 3.235E+005 L/kg (MCI method)
Log Koc: 5.510 (MCI method)
Koc: 3.153E+004 L/kg (Kow method)
LogKoc: 4.499 (Kow method)

Conclusions:

Under the conditions of this study the adsorption and desorption could not be determined in accordance with the guideline because of test material solubility. Therefore specialist chemical prediction software was used to generate estimated values, the predicted Koc was 3.235E+005 L/kg and the LogKoc was 5.510.

Executive summary:

The adsorption/desorption of the test material was investigated in accordance with The Guidelines for the testing of chemicals" State Environmental Protection Administration (SEPA) of China, No. 106 under GLP conditions. Changchun, brown soil of Dalian and red soil of Changsha were used as the absorbents to conduct an adsorption/desorption study with soluble components of the test material in CaCl₂ solution by the balance oscillating method. The results of the preliminary and screening tests indicated that the solubility of the test material in CaCl₂ solution is less than 2.4 x 10^-8 g/L, this study could therefore not be deemed to be applicable with the testing guideline that was used. Therefore, the organic carbon adsorption coefficient of the reaction products was estimated using specialist chemical prediction software EPI-Suite v.4.0 Environmental Protection Agency, which could successfully predict the absorption coefficients. The predicted Koc was 3.235 x 10⁵ L/kg and the Log Koc was 5.510.

Description of key information

Under the conditions of this study the adsorption and desorption could not be determined in accordance with the guideline because of test material solubility. Therefore specialist chemical prediction software was used to generate estimated values, the predicted Koc was 3.235 x 10⁵ L/kg and the Log Koc was 5.510.

Additional information

The adsorption/desorption of the test material was investigated in accordance with The Guidelines for the testing of chemicals" State Environmental Protection Administration (SEPA) of China, No. 106 under GLP conditions. Changchun, brown soil of Dalian and red soil of Changsha were used as the absorbents to conduct an adsorption/desorption study with soluble components of the test material in CaCl₂ solution by the balance oscillating method. The results of the preliminary and screening tests indicated that the solubility of the test material in CaCl₂ solution is less than 2.4 x 10^-8g/L, this study could therefore not be deemed to be applicable with the testing guideline that was used. Therefore, the organic carbon adsorption coefficient of the reaction products was estimated using specialist chemical prediction software EPI-Suite v.4.0 Environmental Protection Agency, which could successfully predict the absorption coefficients. The predicted Koc was 3.235 x 10⁵ L/kg and the Log Koc was 5.510.