4,6-Dichloro-5-fluoropyrimidine

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:

04 - 06 Apr 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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 (incl. QA statement)

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Radiolabelling:

no

Test temperature:

Column temperature: 40 °C

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: Kontron HPLC system with autosampler 465, gradient former 425, pump 422 and column oven 480, UV/VIS detector 430; Software Chromeleon Vers. 6.40, Fa. Dionex
- Type, material and dimension of analytical (guard) column: Material: stainless steel (Bischoff)dimensions: 250 x 4.6 mm stationary phase: Zorbax CN, 5 µm column temperature: 40°C
- Detection system: UV/VIS detection system

MOBILE PHASES
- Type: Methanol / water 55/45 (v/v) (isocratic elution)
- Experiments with additives carried out on separate columns: No
- pH: Not specified
- Solutes for dissolving test and reference substances: Direct injection with eluent

DETERMINATION OF DEAD TIME
- Method: by means of homologous series / by inert substances which are not retained by the column: The dead time is determined by using a homologous series of n-alkyl methyl ketones.

REFERENCE SUBSTANCES
- Identity: Acetanilide, Atrazine, 3,5-Dinitrobenzamide, Linuron, Endosulfan-diol, Fenthion, Pyrazophos, Endosulfan, Diclofop-methyl

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 20 µL injection volume
- Quantity of reference substances: 20 µL injection volume
- Intervals of calibration: Calibration at the start of the test

REPETITIONS
- Number of determinations: 2

EVALUATION
- Calculation of capacity factors k': (tR-t0)/ k' = (capacity factor)
- Calculation of retention times: Retention times were measured
- Determination of the log Koc value: Based on the calibration curve given by the reference substances.

Sample No.:

#1

Type:

Koc

Value:

64

Temp.:

40 °C

Remarks on result:

other: pH not reported

Key result

Sample No.:

#1

Type:

log Koc

Value:

1.8

Temp.:

40 °C

Remarks on result:

other: pH not reported

Details on results (HPLC method):

EQUIPMENT
- Retention times of reference substances used for calibration: 3.970, 4.915, 5.000, 8.050, 9.530, 13.350, 12.750, 15.650, 15.670 (all in minutes)
- Details of fitted regression line (log k' vs. log Koc): A calibration curve was created by using the measured retention times (log k'-values) and the known log K0c-values of the calibration substances for linear regression.
- Average retention data for test substance: 4.730 min.

Validity criteria for the measurement of the adsorption/ desorption:

Target condition according to guideline:	Actual condition according to the study:	Validity criteria met:
Determinations should be run at least in duplicate. The values of log Koc derived from individual measurements should be within a range of 0.25 log unit.	Number of determinations: 2 The values of log Koc between the individual measurements differed in 0.01 log unit.	Yes
To correlate the measured HPLC-retention data of a test substance with its adsorption coefficient Koc, a calibration graph of log Koc versus log k’ has to be established. A minimum of six reference points, at least one above and one below the expected value of the test substance should be used.	A calibration graph with nine reference points was established with log Kocs ranging from 1.25 - 4.20. At least one was beneath and above the measured log Koc of the substance.	Yes
Several mobile phases have been tested and the following two are recommended: - methanol/water (55/45% v/v) - methanol/0.01 M citrate-buffer pH 6.0 (55/45% v/v) HPLC grade methanol and distilled water or citrate-buffer are used to prepare the eluting solvent.	Methanol / water 55/45 (v/v) (isocratic elution) was used as the mobile phase.	Yes

 

Validity criteria fulfilled:

yes

Remarks:

See 'Any other information on results incl. tables'.

Conclusions:

The adsorption coefficient (Koc) of the test item is: 64 (log Koc = 1.80)

Executive summary:

The adsorption coefficient (Koc) of the test substance was determined according to OECD 121 guideline and EEC-guideline 2001/59/EEC C.19. Therefore, nine calibration substances were injected into a HPLC-system under the same analytical conditions (column temperature 40 °C) as the test item. A calibration curve was created by using the measured retention times (log k'-values)and the known log Koc-values of the calibration substances for linear regression.The measured log k'-value of the test item was within the calibrated log k'-range. From the resulted calibration curve and its equation the log Koc of the substance had been interpolated. The adsorption coefficient (Koc) of the test item is: 64 (log Koc = 1.80)

Description of key information

The adsorption coefficient (Koc) of the test substance was determined according to OECD 121 guideline and EEC-guideline 2001/59/EEC C.19. Therefore, nine calibration substances were injected into a HPLC-system under the same analytical conditions (column temperature 40 °C) as the test item. A calibration curve was created by using the measured retention times (log k'-values)and the known log Koc-values of the calibration substances for linear regression.The measured log k'-value of the test item was within the calibrated log k'-range. From the resulted calibration curve and its equation the log Koc of the substance had been interpolated. The adsorption coefficient (Koc) of the test item is: 64 (log Koc = 1.80)

Key value for chemical safety assessment

Koc at 20 °C:

64