Hydroxyl-2-pyridone

Adsorption / desorption

Administrative data

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2002-05-21 to 2002-05-21

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2002

Materials and methods

Test guideline

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

GLP compliance:

yes

Type of method:

HPLC estimation method

Media:

other: HPLC column

Test material

Test material information

Constituent 1

Reference substance name:

Hydroxyl-2-pyridone

EC Number:

212-506-0

EC Name:

Hydroxyl-2-pyridone

Cas Number:

822-89-9

Molecular formula:

C5H5NO2

IUPAC Name:

1-hydroxy-1,2-dihydropyridin-2-one

Test material form:

solid: particulate/powder

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: batch A0103550
- Expiration date of the lot/batch: 01/10/2003
- Purity: 98.9%

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Room temperature in the dark
- Stability under test conditions: Stable

Radiolabelling:

no

Study design

HPLC method

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: Column
- Type, material and dimension of analytical (guard) column: Hypersil BDS-CN; 150 x 4.6 (ID) mm; dp=5 µm (Alltech, Deerfield, USA)
- Detection system: UV at 210 nm
- Column temperature: 35°C

MOBILE PHASES
- Type: 55/45 methanol/0.05 M phosphate buffer added to 400 mL Milli-Q water, adjusted to pH 7.0 with 1 M sodium hydroxide and filled to 450 mL with Milli-Q water.
- pH: 7
- A solution of the reference substance in methanol, at a concentration of 1.5 g/L was used. This solution was diluted by a factor of 100 with mobile phase. As reference blank solution, 99/1 (v/v) mobile phase/methanol was used.
- A 5.3 g/L solution of formamide in methanol was diluted by a factor 10 with mobile phase. This solution was used for the determination of t0 (retention time of the unretarded component). As blank formamide solution, 10% methanol in mobile phase was used.
- A 1.1 g/L stock solution of Oxypyrion was prepared in mobile phase. The test solution was prepared by diluting the stock solution by a factor 10 with mobile phase. As blank solution mobile phase was used.

REFERENCE SUBSTANCES
- Identity: Phenol

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 1 µL
- Quantity of reference substances: 1 µL

REPETITIONS
- Number of determinations: two for the reference substance and the test item solution, and one for the mobile phase, the blank solution and the formamide solution

EVALUATION
- Calculation of capacity factors k': the capacity factor is calculated from the retention of the substance concerned and the unretarded component.
- Determination of the log Koc value: Using the capacity factors of the reference substances, a plot of log Koc (x-value) versus log k' (y-value) was constructed, using linear regression analysis. The log Koc value of each component of the test substance was calculated from the following equation: log k'= a * log Koc + b

Batch equilibrium or other method

Analytical monitoring:

no

Results and discussion

Adsorption coefficient

Adsorption coefficient 1

Key result

Type:

Koc

Value:

< 21 dimensionless

pH:

7

Temp.:

35 °C

Adsorption coefficient 2

Key result

Type:

log Koc

Value:

< 1.3 dimensionless

pH:

7

Temp.:

35 °C

Results: HPLC method

Details on results (HPLC method):

- Retention times of reference substances used for calibration: 2.3 minutes
- Graph of regression line attached: no
- Average retention data for test substance: 5 minutes

Applicant's summary and conclusion

Validity criteria fulfilled:

not specified

Conclusions:

The HPLC method (OECD 121) using soil-adsorption-reference data was applied for the determination of the adsorption coefficient (Koc) of Oxypyrion. Testing with the ionised form was performed at pH 7. In the chromatogram of Oxypyrion, a broad tailing peak was observed. Because retention time of the major part of the peak was smaller than the retention time of the reference substance phenol, it was concluded that at pH 7 the adsorption coefficient of the test substance (Koc) is < 21 (log Koc < 1.3). The results of the test can be considered reliable without restriction.