2-ethylhexyl nitrate

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 March 2010 to 21 April 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: compliant to GLP and testing guideline; adequate coherence between data, comments and conclusions

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:

yes

Remarks:

The reference item 4,4-DDT was expired since 31 October 2009

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Test temperature:

The temperature during the analytical phase was around 22 °C.

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: Autosampler, HPLC pump, Ultrasonic tank, Magnetic stirrer, Balance, Usual laboratory apparatus
- Column: Supelco - Length: 25 cm
- Particle size: 5.0 µm - Internal diameter: 4.6 mm
- Stationary phase: Supelcosil LC-CN
- Flow rate: 0.9 mL/min
- Injected volume: 40 µL - Wave length analysis: 210 nm
- Detection system: UV visible detector Hitachi L-4250

MOBILE PHASES
- Type: Methanol / water 45/55 v/v
- Solutes for dissolving test and reference substances: methanol

DETERMINATION OF DEAD TIME
- Method: by inert substances which are not retained by the column
Preparation of the thiourea solution

REFERENCE SUBSTANCES
- Identity: Acetanilide, methylbenzoate, isoproturon, 1,2,3-trichlorobenzene, pyrazophos and 4,4'-DDT

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 100 mg
- Quantity of acetanilide, 1,2,3-trichlorobenzene, pyrazophos or 4,4'-DDT introduced in the column: 10 mg
- Quantity of methylbenzoate introduced in the column: 20 mg
- Quantity of isoproturon introduced in the column: 5 mg

REPETITIONS
- Number of determinations: 2

EVALUATION
- The adsorption / desorption coefficient is given by the following equation: Logk' = a log Koc + b where k' is the capacity factor of the chromatographic column, a and b the coefficient of the calibration curve
The coefficients of the calibration curve are obtained through the chromatographic analysis of at least six analytical reference items with known adsorption coefficient.

Type:

log Koc

Value:

3.75

Temp.:

22 °C

Details on results (HPLC method):

The results of the adsorption coefficient determination of 2-ETHYLHEXYL NITRATE are given in tables (see below).

First run: Using the Capacity factor and the adsorption coefficient of the reference items, the following calibration curve was obtained: log k' = 0.380 logKoc - 0.878

Second run: Using the Capacity factor and the adsorption coefficient of the reference items, the following calibration curve was obtained: log k' = 0.382 logKoc - 0.881

Variation in the retention times of the reference items are very small. Therefore a stable configuration of the HPLC column can be assumed.

First run:

Products	Mean Retention Time (min)	Value of the Capacity factor k'	Value of log k'	Value of log Koc
Acetanilide	4.68	0.28	-0.55	1.25
Methyl benzoate	5.80	0.59	-0.23	1.80
Isoproturon	6.73	0.84	-0.074	1.86
1,2,3 -trichlorobenzene	12.22	2.35	0.37	3.16
Pyrazophos	20.15	4.52	0.66	3.65
4,4' DDT	55.37	14.2	1.15	5.63
Test item	16.45	3.51	0.54	3.74

Second run:

roducts	Mean Retention Time (min)	Value of the Capacity factor k'	Value of log k'	Value of log Koc
Acetanilide	4.67	0.28	-0.55	1.25
Methyl benzoate	5.80	0.59	-0.23	1.80
Isoproturon	6.74	0.85	-0.072	1.86
1,2,3 -trichlorobenzene	12.32	2.38	0.38	3.16
Pyrazophos	20.41	4.59	0.66	3.65
4,4' DDT	56.19	14.4	1.16	5.63
Test item	16.63	3.56	0.55	3.75

Validity criteria fulfilled:

yes

Conclusions:

The adsorption / desorption coefficient of 2-ETHYLHEXYL NITRATE is equal to 3.75

Key value for chemical safety assessment

Koc at 20 °C:

5 623