Propanoic acid, 2-hydroxy-, 2-ethylhexyl ester, (2S)-

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:

2010

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

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))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Media:

other: HPLC column

Radiolabelling:

no

Test temperature:

Column temperature 35 ± 1 °C

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: Alliance Separation Module 2695
- Type, material and dimension of analytical (guard) column: Hypersil BDS-CN, 150 mm ± 4.6 mm i.d., dp = 5 µm
- Detection system: Dual λ Absorbance Detector 2487

MOBILE PHASES
- Type: 55/45 (v/v) methanol/water
- pH: neutral
- Solutes for dissolving test and reference substances: methanol; The stock solutions were diluted to obtain an end solution of 55/45 (v/v) methanol/water.

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

REFERENCE SUBSTANCES
- Identity: Acetanilide, Atrazine, Monuron, 2,5-Dichloroaniline, Benzoic acid phenylester, Fenthion, Phenanthrene, 2,4-DDT


DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 10 µl (7.7 µg)
- Quantity of reference substances: 10 µl (5.5 µg)

REPETITIONS
- Number of determinations: The reference substance and test substance solutions were injected in duplicate. Blank solutions were analysed by single injection.

EVALUATION
- Calculation of capacity factors k': k' = (tr - t0)/t0 where:
tr = retention time
t0 = mean column dead time

- Calculation of retention times: Taken from the HPLC chromatograms
- Determination of the log Koc value: log k' = a logKoc + b; where: a = slope, b = intercept

Analytical monitoring:

not required

Type:

Koc

Value:

330

Temp.:

35 °C

Remarks on result:

other: HPLC column temperature 35 °C

Type:

log Koc

Value:

2.52

Temp.:

35 °C

Remarks on result:

other: HPLC column temperature 35 °C

Details on results (HPLC method):

HPLC chromatograms of the test substance solution and corresponding blank solution are shown in Figure 1 (see below).
- Retention times of reference substances used for calibration: See Table 1 below
- Details of fitted regression line (log k' vs. log Koc): The equation of the regression line was: log k’ = 0.264 × log Koc – 1.214 (r = 0.97, n = 16).
- Graph of regression line attached: Figure 2 (see illustration below) shows the calibration curve of the log k’ of the reference substances as function of log Koc.
- Average retention data for test substance: See Table 1 below

Table 1: K_ocof the test substance

Substance	tr,1 [min]	tr,2 [min]	mean tr (n=2)	log Koc	Koc	Area %
Formamide (t0)	1.961	1.960	1.961
Acetanilide	2.165	2.165		1.26
Atrazine	2.307	2.307		1.81
Monuron	2.351	2.350		1.99
2,5-Dichloroaniline	2.525	2.524		2.55
Benzoic acid phenylester	2.758	2.757		2.87
Fenthion	3.268	3.267		3.31
Phenanthrene	3.418	3.417		4.09
2,4-DDT	4.903	4.904		5.63
Impurity I	1.301	1.301	1.301	<1.26	<1.8x10^1	0.37
Test substance	2.518	2.517	2.518	2.52	3.3x10^2	98.7
Impurity II	2.804	2.804	2.804	3.21	1.6x10^3	0.91

 

Validity criteria fulfilled:

yes

Conclusions:

The log Koc of 2-ethylhexyl-S-lactate is 2.52.

Executive summary:

The HPLC method using soil-adsorption-reference data was chosen for the determination of the adsorption coefficient of PURASOLV^®EHL (2-ethylhexyl-S-lactate).

The K_ocand log K_ocvalue of the test substance was:

	neutral pH
	Koc	log Koc
Test substance	3.3 × 10²	2.52

Description of key information

The log Koc of 2-ethylhexyl-S-lactate is 2.52.

Key value for chemical safety assessment

Koc at 20 °C:

330

Additional information

[LogKoc: 2.52]