SUMILIZER GP

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:

14 - 18 Mar 2003

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

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))

Version / remarks:

2001

Qualifier:

according to guideline

Guideline:

EU Method C.19 (Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Liquid Chromatography (HPLC))

Version / remarks:

2001

GLP compliance:

yes (incl. QA statement)

Remarks:

Federal Office of Public Health, Bern, Switzerland

Type of method:

HPLC estimation method

Media:

soil

Radiolabelling:

no

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: Varian autosampler 9095, Varian pump 9012, Varian detector 9050, Jones column oven 7990
- Type, material and dimension of analytical (guard) column: LiChrospher 100 CN, part, size 5 µm, 250 mm x 4 mm
- Detection system: UV (210 nm for reference items and formamide and 250 nm for test item solutions)

MOBILE PHASES
- Type: LiChrospher 100 CN, part, size 5 /vm, 250 mm x 4 mm
- Experiments with additives carried out on separate columns: yes / no
- pH: 8.5
- Solutes for dissolving test and reference substances: acetonitrile

DETERMINATION OF DEAD TIME
- Method: by means of homologous series: Formamide (50 µL) was diluted to 50 mL with acetonitrile to obtain a stock solution. The stock solution (36 µL) was diluted to 1 mL with acetonitrile. This formamide solution was injected three times for the determination of the dead time of the HPLC system.)

REFERENCE SUBSTANCES
- Identity: phenol, isoproturon, linuron, pyrazophos, Diclofop-methyl, 2,4-DDT (mixed standard)

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 176.5 µg/mL
- Quantity of reference substances: phenol: 5.5 µg/mL, 5.4 µg/mL isoproturon, 3.6 µg/mL linuron, 39 µg/mL pyrazophos, 8.4 µg/mL diclofop-methyl, 11.6 µg/mL (mixed standard)
- Intervals of calibration:

REPETITIONS
- Number of determinations: 3 (test item), 6 (mixed standard)

EVALUATION
- Calculation of capacity factors k': the capacity factor (k’) is calculated from the retention time of the reference items, the test item (tr) and an unretarded item (t0)
- Determination of the log Koc value: The log k’ value of the test item was used to calculate its log K0c value.

Type:

log Koc

Value:

> 5.63

Remarks on result:

other: Limit value based on 2,4-DDT

Type:

Koc

Value:

>= 1 291 569 - <= 1 406 043 L/kg

pH:

8.1

Remarks on result:

other: first peak, extrapolated

Type:

log Koc

Value:

6.1 dimensionless

pH:

8.1

Remarks on result:

other: first peak, extrapolated

Type:

Koc

Value:

>= 38 000 000 - <= 47 000 000 L/kg

pH:

8.1

Remarks on result:

other: second peak, extrapolated

Type:

log Koc

Value:

>= 8.6 - <= 8.7 dimensionless

pH:

8.1

Remarks on result:

other: second peak, extrapolated

Details on results (HPLC method):

- Retention times of reference substances used for calibration (mean values): phenol: 2.89 min, isoproturon: 3.20 min, linuron: 3.62 min, pyrazophos: 4.13 min, Diclofop-methyl: 4.82 min, 2,4-DDT: 6.09 min
- Details of fitted regression line (log k' vs. log Koc): r = 0.990
- Graph of regression line attached: yes
- Average retention data for test substance: Test item peak 1: 7.31 min, test item peak 2: 15.63 min

Tale 1: Results of linear regression of Log k' vs. Log Koc

Substances	Number of analyses	Mean retention time (min)	k’	Log k‘	Log Koc
Formamide (=dead time)	3	2.17	-	-	-
Phenol	6	2.89	0.33	-0.48	1.32
Isoproturon	6	3.20	0.47	-0.32	1.86
Linuron	6	3.62	0.67	-0.18	2.59
Pyrazophos	6	4.13	0.90	-0.04	3.65
Diclofop-methyl	6	4.82	1.22	0.09	4.20
2,4-DDT	6	6.09	1.81	0.26	5.63
Linear regression	Slope =				0.167
	y-axis intercept =				-0.649
	Coefficient of regression =				0.990

Table 2: Results of test item analyses

Number of analyses	Retention time (min)	k’	Log k‘	Log Koc	Mean log Koc	Koc	Mean Koc
1 Test item Peak
1	7.28	2.35	0.37168	6.1	6.1	1291569	1343527
2	7.31	2.37	0.37397	6.1		1332967
3	7.35	2.39	0.37784	6.1		1406043
2. Test item Peak
1	15.35	6.07	0.78319	8.6	8.6	3.8E+08	4.29E+08
2	15.69	6.23	0.79432	8.6		4.4E+08
3	15.87	6.31	0.80009	8.7		4.7E+08

Validity criteria fulfilled:

not applicable

Description of key information

Log Koc = 6.1 - 8.7 (OECD 121)

Additional information

The adsorption coefficient (Koc) of the test item was determined in a GLP study performed according to OECD 121.

The test item solution of 176.5 µg/mL was injected three times. A combined reference substance solution containing phenol, isoproturon, linuron, pyrazophos, Diclofop-methyl and 2,4-DDT was injected six times. The log Koc was calculated using a regression curve (log k' vs. log Koc). The reference items covered the range of log Koc 1.32 to 5.63.

The retention times of the test item in the HPLC chromatogram are longer than the retention time of the highest reference item used. Therefore, the logarithm of the adsorption coefficient of the test item was extrapolated from the regression curve to be 6.1 (first test item peak) and 8.6 (second test item peak). The Koc of the test item were calculated to be 1343527 and 4.3 x 10^8 indicating a strong potential to adsorb to soil and sediment.