Registration Dossier

Administrative data

Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
June 01, 2007- June 06, 2007
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study with acceptable restriction. Study of ammonium salt of MeDONA hydrolysis product.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report date:
2007

Materials and methods

Test guidelineopen allclose all
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))
Deviations:
no
Qualifier:
according to guideline
Guideline:
other: EC no. 67/548/EEC Annex V, Part C.19: "Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC)"
Deviations:
no
GLP compliance:
yes
Type of method:
HPLC estimation method
Media:
soil/sewage sludge

Test material

Constituent 1
Reference substance name:
E-19729
IUPAC Name:
E-19729

Study design

HPLC method

Details on study design: HPLC method:
EQUIPMENT
- Apparatus: HPLC System Agilent 1100 series;
- Type, material and dimension of analytical column: LiChrospher 100 CN 5 µm by Duratec (18304-04), stainless steel, dimensions: 250 mm x 4.6 mm
- Detection system: UV/Vis detector G1315B by Agilent, detection wavelength at 210 nm (dead time marker and calibration substances), 200 nm (test item)

MOBILE PHASES:
- Type: 50/50 (v/v) MethanoI/NH4H2PO4 (c=0.05 mol/l)
- Experiments with additives carried out on separate columns: no
- pH: 7.1
- Solutes for dissolving test and reference substances: dead time marker and calibration substances were dissolved in acetonitrile and diluted in the mobile phase; test substance was dissolved and diluted in the mobile phase.

DETERMINATION OF DEAD TIME
- Method: by inert substances which are not retained by the column: 22.76 µg of formamide (CAS# 75-12-7) was diluted in mobile phase and resulted a mean dead time of 3.24 minutes.

REFERENCE SUBSTANCES
- Identity:
Acetanilide
Atrazine
Monuron
Triadimenol
Linuron
Pyrazophos
Diclofop-methyl

It is notable that the reference substances are aromatic compounds and/or pesticides. The reference substances are approved for use in the method, but bear little or no structural similarity to the test substance. This is a limitation of the test guideline.

The reference substances are approved for use in the method, but bear little or no structural similarity to the test substance.

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 21.82 µg
- Quantity of reference substances: 0.77 - 1.05 µg
- Intervals of calibration: None

REPETITIONS
- Number of determinations: Two (duplicate) injections

EVALUATION
- Calculation of capacity factors k': k' = (Tr - T0) / T0, where: Tr = retention time;
T0 = mean column dead time (formamide peak);

- Calculation of retention times: mean retention times were taken for the unretained and test substance retention times only. Retention times for the duplicated injections of the reference substance peaks were used to generate the regression curve.

- 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 Koc = a +b x logk

Results and discussion

Adsorption coefficient
Type:
log Koc
Value:
<= 1.3

Results: HPLC method

Details on results (HPLC method):
The test substance has log Koc value below the lowest calibration substance (acetanilide).

- Retention times of reference substances used for calibration: See table 1
- Details of fitted regression line (log k' vs. log Koc):
1st measurement: a = 2.38, b = 2.71, r^2 = 0.98192, log Koc < 1.25
2nd measurement: a = 2.38, b = 2.72, r^2 = 0.9822, log Koc < 1.25

- Graph of regression line attached: See Figure 1.
- Average retention data for test substance: 3.92 min.

Any other information on results incl. tables

Table 1. Koc determination of E-19729

Substance

Tr,1 [min]

Tr,2 [min]

mean Tr (n=2)

log Koc

Formamide (t0)

3.24

3.24

3.24

 

 

 

 

 

 

Acetanilide

4.43

4.44

 

1.25

Atrazine

5.08

5.06

 

1.81

Monuron

5.45

5.46

 

1.99

Triadimenol

6.80

6.80

 

2.40

Linuron

8.10

8.09

 

2.59

Pyrazophos

12.26

12.23

 

3.65

Diclofop-methyl

16.87

16.83

 

4.20

 

 

 

 

 

E-19729

3.92

3.92

3.92

< 1.25

Applicant's summary and conclusion

Conclusions:
Log Koc value of test substance was ≤1.3.
Executive summary:

MeDONA is hydrolytically unstable, producing a strong acid which will be deprotonated at environmentally relevant pH. The tested substance is the ammonium salt of the MeDONA hydrolysis product.

Log Koc values of test substance (CAS# 958445-44-8) were assessed according to OECD Guideline TG121 and EC no. 440/2008, Part C.19: "Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC)" with mobile phase buffered to pH 7.1. Under the analytical conditions used, the test substance had a log Koc value below the lowest calibration substance (acetanilide), which has a log Koc of 1.25. Therefore, MeDONA hydrolyzes to a substance with log Koc ≤1.3.

The study was conducted according to internationally accepted 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 classified as reliable with restrictions.