Boronic acid, B-(2-fluoro-3-methoxyphenyl)-

Adsorption / desorption

Administrative data

Endpoint:

adsorption / desorption, other

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13th July 2018 to 2nd August 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: MEP PR China. The Guidelines for the Testing of Chemicals: No. 106 'Adsorption-desorption using a batch equilibrium method (2013)

GLP compliance:

yes

Type of method:

HPLC estimation method

Media:

soil

Test material

Test material information

Constituent 1

Reference substance name:

(2-fluoro-3-methoxyphenyl)boronic acid

EC Number:

609-099-0

Cas Number:

352303-67-4

Molecular formula:

FC6H3(OCH3)B(OH)2

IUPAC Name:

(2-fluoro-3-methoxyphenyl)boronic acid

Test material form:

solid: particulate/powder

Study design

Test temperature:

20 - 25 oC

HPLC method

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: Waters e2695-2489 HPLC
- Type, material and dimension of analytical (guard) column: Agent Eclipse XDB-C18 5μm (4.6ID x 250nm)
- Detection system: UV

MOBILE PHASES
- Type: Acetonitrile:0.1% formic acid water solution (30:70)
- Solutes for dissolving test and reference substances: acetonitrile

METHOD LINEARITY
Method linearity was evaluated by analysing calibration standards and plotting areas v concentration.

The LOD is 0.5mg/L

Batch equilibrium or other method

Matrix properties

Matrix properties 1

Matrix no.:

#1

Matrix type:

other: Black

% Clay:

33.4

% Silt:

25.9

% Sand:

40.7

% Org. carbon:

1.16

pH:

6.54

CEC:

28.2 other: cmol/kg

Matrix properties 2

Matrix no.:

#2

Matrix type:

other: Red

% Clay:

44.5

% Silt:

14.3

% Sand:

41.2

% Org. carbon:

0.57

pH:

5.02

CEC:

12.7 other: cmol/kg

Matrix properties 3

Matrix no.:

#3

Matrix type:

other: Paddy

% Clay:

18.1

% Silt:

17.1

% Sand:

64.8

% Org. carbon:

1.14

pH:

6.88

CEC:

6.8 other: cmol/kg

Matrix properties 4

Matrix no.:

#4

Matrix type:

other: Moisture

% Clay:

19.9

% Silt:

17.9

% Sand:

62.2

% Org. carbon:

0.38

pH:

7.82

CEC:

1.9 other: cmol/kg

Matrix properties 5

Matrix no.:

#5

Matrix type:

other: Aquic Brown

% Clay:

16.5

% Silt:

42.8

% Sand:

40.7

% Org. carbon:

1.19

pH:

5.47

CEC:

7.3 other: cmol/kg

Details on matrix:

COLLECTION AND STORAGE
- Geographic location: Huai'an - Jiangsu Province, Shenyang - Liaoning Province, Fu zhu City - Fujian Province, Suihua - Heilongjiang Province and Heze - Shendong Province
- Storage conditions: Room Temperature
- Soil preparation: 2 mm sieved

PROPERTIES
- Soil texture
- % sand: 40.7, 41.2, 64.8, 62.2 and 40.7
- % silt: 25.9, 14.3, 17.1, 17.9 and 42.8
- % clay: 33.4, 44.5, 18.1, 19.9 and 16.5
- pH: 6.54, 5.02, 6.88, 7.82 and 5.47
- Organic carbon (%): 1.16, 0.57, 1.14, 0.38 and 1.9
- CEC (cmol/kg): 28.2, 12.7, 6.8, 1.9 and 7.3
- Moisture (%): 3.3, 1.0, 1.8, 0.7 and 1.6
- Biomass (mg/kg): 360.24, 308.99, 805.86, 75.85 and 267.41

Details on test conditions:

Solution Preparation: 0.01 M CaCl2 was prepared by dissolving 4.44g CaCl2 into 4L water.

1) Test 1 - Preliminary Study
(a) Solution/soil ratio 1:1 - red and moisture soil
5.0g soil with 5 mL solution (0.01 M CaCl2) was agitated at 160rpm overnight at 20-25 0C in order to achieve pre-equilibrium. Then soil samples of 40mg/L were prepared by addition of aliquots of stock solution. Another 24 hours agitation was run to reach adsorption equilibrium. Both the concentration of aqueous and oil phases were measured on 2nd, 4th, 6th, 16th and 24th hours to calculate the adsorption percentage and mass balance rate.
A blank run per soil with the same amount of soil with 0.01 M CaCl2 solution (without test substance) were subjected to the same test procedure.

(b) Solution/soil ratio 10:1 - black soil, aquic brown soil and paddy soil
1.0g soil with 10mL solution (0.01 M CaCl2) was agitated at 160rpm overnight at 20-25 0C in order to achieve pre-equilibrium. Then soil samples of 40mg/L were prepared by addition of aliquots of stock solution. Another 24 hours agitation was run to reach adsorption equilibrium. Both the concentration of aqueous and oil phases were measured on 2nd, 4th, 6th, 16th and 24th hours to calculate the adsorption percentage and mass balance rate. A blank run per soil with the same amount of soil with 0.01 M CaCl2 solution (without test substance) were subjected to the same test procedure.

2) Desorption kinetics
Five soils were weighed out and 0.01M CaCl2 was added into centrifugal tubes (ratios as above). The tubes were sealed and agitated overnight to reach pre-equilibrium. Samples with concentrations of 40mg/L were prepared by addition of the standard stock solution and agitated for the adsorption equilibrium time. The sample was centrifuged at 5000rpm for 3 mins. The centrifugal volume was recorded and the aqueous phase was removed. This was replaced by an equal volume of 0.01M CaCl2 solution without the test material. The sample was agitated and analysis was done at 2, 4, 6 ,16 and 24 hours

3) Tier 3 - adsorption isotherms
Five soils were weighed out and 0.01M CaCl2 was added into centrifugal tubes (ratios as above). The tubes were sealed and agitated overnight to reach pre-equilibrium. Samples with concentrations of 8, 20, 50, 100 and 200 mg/L were prepared by addition of the standard solution and agitated for the adsorption equilibrium time. The sample was centrifuged at 5000rpm for 3 mins. The concentration of the aqueous phase or both soil and aqueous phase was determined

4) Desorption isotherms
After the absorption isotherm test and removal of the aqueous phase, an equal volume of 0.01mol/L CaCl2 without test item was added to the soil phase. The samples were agitated for the desorption equilibrium time at 20-25oC. The sample was centrifuged at 5000rpm for 3 mins. The concentration of the aqueous phase was determined.

Duration of adsorption equilibration

Duration of adsorption equilibration 1

Sample No.:

#1

Duration:

24 h

Initial conc. measured:

40 mg/kg soil d.w.

Temp.:

20 - 25 °C

Duration of adsorption equilibration 2

Sample No.:

#2

Duration:

24 h

Initial conc. measured:

40 mg/kg soil d.w.

Temp.:

20 - 25 °C

Duration of adsorption equilibration 3

Sample No.:

#3

Duration:

24 h

Initial conc. measured:

40 mg/kg soil d.w.

Temp.:

20 - 25 °C

Duration of adsorption equilibration 4

Sample No.:

#4

Duration:

24 h

Initial conc. measured:

40 mg/kg soil d.w.

Temp.:

20 - 25 °C

Duration of adsorption equilibration 5

Sample No.:

#5

Duration:

24 h

Initial conc. measured:

40 mg/kg soil d.w.

Temp.:

20 - 25 °C

Duration of desorption equilibration

Duration of desorption equilibration 1

Sample no.:

#1

Duration:

24 h

Temp.:

25 °C

Duration of desorption equilibration 2

Sample no.:

#2

Duration:

24 h

Temp.:

25 °C

Duration of desorption equilibration 3

Sample no.:

#3

Duration:

24 h

Temp.:

25 °C

Duration of desorption equilibration 4

Sample no.:

#4

Duration:

24 h

Temp.:

25 °C

Duration of desorption equilibration 5

Sample no.:

#5

Duration:

24 h

Temp.:

25 °C

Computational methods:

-

Results and discussion

Adsorption coefficient

Adsorption coefficient 1

Key result

Sample No.:

#1

Type:

Koc

Value:

543.1

Matrix:

Black soil

% Org. carbon:

1.16

Adsorption coefficient 2

Key result

Sample No.:

#2

Type:

Koc

Value:

175.6

Matrix:

Red soil

% Org. carbon:

0.57

Adsorption coefficient 3

Key result

Sample No.:

#3

Type:

Koc

Value:

406.1

Matrix:

Paddy soil

% Org. carbon:

1.14

Adsorption coefficient 4

Key result

Sample No.:

#4

Type:

Koc

Value:

243.2

Matrix:

Moisture soil

% Org. carbon:

0.38

Adsorption coefficient 5

Key result

Sample No.:

#5

Type:

Koc

Value:

197.4

Matrix:

Aquic brown soil

% Org. carbon:

1.19

Adsorption coefficient 6

Key result

Sample No.:

#1

Type:

Kd

Value:

6.3

Matrix:

Black soil

% Org. carbon:

1.16

Adsorption coefficient 7

Key result

Sample No.:

#2

Type:

Kd

Value:

1.001

Matrix:

Red soil

% Org. carbon:

0.57

Adsorption coefficient 8

Key result

Sample No.:

#3

Type:

Kd

Value:

4.629

Matrix:

Paddy soil

% Org. carbon:

1.14

Adsorption coefficient 9

Key result

Sample No.:

#4

Type:

Kd

Value:

0.924

Matrix:

Moisture soil

% Org. carbon:

0.38

Adsorption coefficient 10

Key result

Sample No.:

#5

Type:

Kd

Value:

2.349

Matrix:

Aquic brown soil

% Org. carbon:

1.19

Results: Batch equilibrium or other method

Mass balance (%) at end of adsorption phase

Mass balance (%) at end of adsorption phase 1

Sample no.:

#1

Duration:

24 h

% Adsorption:

95.7

Mass balance (%) at end of adsorption phase 2

Sample no.:

#2

Duration:

24 h

% Adsorption:

104.7

Mass balance (%) at end of adsorption phase 3

Sample no.:

#3

Duration:

24 h

% Adsorption:

96.7

Mass balance (%) at end of adsorption phase 4

Sample no.:

#4

Duration:

24 h

% Adsorption:

94.6

Mass balance (%) at end of adsorption phase 5

Sample no.:

#5

Duration:

24 h

% Adsorption:

97.3

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The Kd values were 1.001, 6.3, 4.629, 0.924 and 2.349 for red, black, paddy, moisture and aquic brown soils respectively.  The Koc values were 175.6, 543.1, 406.1, 243.2 and 197.4 for red, black, paddy, moisture and aquic brown soils respectively.  

The desorption ratio ranged from 24.8 - 43.6% in the five soil types at 24 hours.

Executive summary:

The adsorption-desorption behaviour of FMBPA (purity 100.2%) on soil was assessed according to the Guidelines of SEPA PR China, the Guidelines Chemical Testing Good Laboratory Practice (HJ/T 155-2004). 

Ther HPLC method was used to detect FMBPA. Chromatographic separation was carried out on an Agent Eclipse XDB-C18 5μm (4.6ID x 250nm) column with mobile phase consisting of acetonitrile and 0.1% formic acid in Ultra Water (30/70) at a flow rate of 0.8mL.min. The wavelenght was 210nm. The injection volume was 20μl. The minimum detection concentration was 0.5mg/L for the aqueous phase and 5mg/kg for the soil phase. 

Five typical chinese soils (red soil, black soil, paddy soil, moisture soil and aquic brown soil) significantly in cation exchange capacity, clay content, organic matter content and pH value were used in the test. 

The air dried soils were weighed into a polypropylene centrifuge tube (250ml) and 0.01M CaCl₂ solution added. The soil to CaCl₂ solution ratio was 1:1 (5g soil and 5.0ml of 0.01M CaCl₂), 1:10 (1g soil and 10.0ml of 0.01M CaCl₂) and 1:100 (1g soil and 100.0ml of 0.01M CaCl₂). The test item concentration was set at 40mg/L and the adsorption equilibrium time was 24 hours. 

The initial concentration was 40ml/L and the soil/solution ratios were 1:1 for red and moisture soils, 1:10 for black, paddy and aquic brown soils. The test substance in aqueous phase was analysed at 2, 4, 6, 16 and 24 hours contact time. The curve was prepared using concentration and time. The adsorption ratio ranged from 24.8 - 50.8% for the five types of soil at 24 hours. The recovery of mass balance ranged from 94.6 - 104.7% for the five types of soil. The K_d values were 1.001, 6.3, 4.629, 0.924 and 2.349 for red, black, paddy, moisture and aquic brown soils respectively.  The K_oc values were 175.6, 543.1, 406.1, 243.2 and 197.4 for red, black, paddy, moisture and aquic brown soils respectively.  

The desorption ratio ranged from 24.8 - 43.6% in the five soil types at 24 hours. The desorption equilibrium time of 24 hours was selected.  

Adsorption isotherm test: Five concentrations of 8, 20, 50, 100 and 200 mg/L were used for the definitive test. The soil ratios were 1:1 on red and moisture soils and 1:10 on black, paddy and aquic brown soils.