(2S)-1-isopropoxy-1-oxopropan-2-yl pivalate

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:

2014-11-20 to 2014-11-21

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))

Version / remarks:

2001

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))

Version / remarks:

2008

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

inspected on June 03-05, 2013 / signed on November 05, 2013

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Specific details on test material used for the study:

- Storage condition of test material: Keep in the dark at 0 - 10 °C, under nitrogen
- Stability under test conditions: Not specified, assumed to be stable

Radiolabelling:

no

Test temperature:

23.4-23.7 °C (23.6 °C)

Details on study design: HPLC method:

Analysis of ST 11 C 13 was carried out by HPLC-DAD. The test and reference items were dissolved in methanol, diluted to mobile phase ratio and injected into the HPLC-DAD system.

EQUIPMENT
- Test system: Analytical HPLC-column (based on silica matrix) packed with a cyanopropyl solid phase containing non-polar and polar moieties coupled to DAD. Methanol and HPLC water in a ratio 55 : 45 was used as mobile phase.
- HPLC-DAD system
HPLC AG|LENT 1100 consisting of:
Auto sampler : G1329A
Auto sampler thermostat : G1330B
Degasser . G1322A
Column oven : G1316A
Detector (test system) . G1315B
Pump : G1312A
Software " Empower 2 (Build No: 2154), WATERS
- HPLC column: YMC-Pack Cyano, 250 x 4.0 mm, S-5 µm, 12 nm, batch 11334, YMC EUROPE GMBH

CONDITIONS OF ANALYSIS
Injection volume: 10 µL
Mobile phase: Methanol : HPLC water (55 : 45)
Flow: 0.8 mL/min
Wavelength: 210, 210, 240, 220, 245, 245, 235, 250 and 250 for Sodium nitrate, Acetanilide, Atrazine, Monuron, Linuron, Phenyl benzoate, Fenthion and Phenanthrene, respectively
Run time: 20 minutes for test item, Fenthion and Phenanthrene; 10 minutes for the others

MOBILE PHASES
- Methanol : HPLC water (55 : 45)
This mobile phase allowed the determination of the adsorption coefficient (Koc) for the test item in a reasonable period with suitable chromatographic properties for the test and reference items. No buffer was used because the adsorption coefficient (Koc) of the test item is independent on the pH value for this test item.
- Column temperature: 20 - 25 °C
- System Suitability: The suitability of the column was confirmed acc. to the guidelines by the data given below: log k' > 0 for log Koc = 3.02 (Endosulfan-diol) and log k' > -0.4 for log Koc = 1.95 (3-Nitrobenzamide) by using methanol/water 55/45 % as mobile phase.

DETERMINATION OF DEAD TIME
- Method: NaNO3 was used for determination of dead time.

REFERENCE SUBSTANCES
- Identity: Acetanilide, Atrazine, Monuron, Linuron, Phenyl benzoate, Fenthion and Phenanthrene

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: Single (three injections)
Stock solutions 100 mg/L each in methanol; 100 mg/L in HPLC-water for NaNO3
Test concentration: 5 mg/L
- Replicates: Two injections (one before and one after the analysis of the test item); Three injections for NaNO3 at the beginning of the sample set.
- Calibration: Calibrations were performed using seven reference items for soil and six for sewage sludge with known log Koc values.
TEST ITEM
Stock solution: 1000 mg/L in methanol
Test concentration: 550 mg/L
Dilution: with HPLC water to mobile phase ratio
Replicates: Single (three injection)

EVALUATION
- Calculation of capacity factors k': (tR-t0)/t0
- Determination of the log Koc value: log Koc = a ' log k' + b
Two individual log Koc values for soil and for sewage sludge for the test item were derived under consideration of the first and second calibration. Finally a mean value for soil and for sewage sludge was calculated from, these individual log Koc values.

tR Retention time [min]
to Dead time [min]
k' Capacity factor
a: slope of the calibration graph
b: y-intercept of calibration graph
Finally, a mean value was calculated from these individual log Koc values.

Key result

Type:

log Koc

Remarks:

soil

Value:

2 dimensionless

Temp.:

23.6 °C

Matrix:

silica matrix

Key result

Type:

log Koc

Remarks:

sewage sludge

Value:

2.1 dimensionless

Temp.:

23.6 °C

Matrix:

silica matrix

Details on results (HPLC method):

- Dead Time of the HPLC-System: The HPLC dead time (to) was determined by threefold injection of a solution of 5 mg/L NaNO3. Dead time of the HPLC system: 1.606 ± 0.001
- Retention times of reference substances used for calibration: See table 5.4.1/1

Table 5.4.1/1: Capacity Factors (k') of the Reference Items for Soil and Sewage Sludge

Reference item	log Koc, soil	log Koc, sewage sludge	1.calibration			2.calibration
			tR1 (min)	K’	Log k’	tR2 (min)	K’	Log k’
Acetanilide	1.26	1.52	4.073	1.536	0.186	4.076	1.538	0.187
Atrazine	1.81	1.66	4.743	1.953	0.291	4.749	1.957	0.292
Monuron	1.99	1.46	5.073	2.159	0.334	5.078	2.162	0.335
Linuron*	2.59	2.43	7.951	3.951	0.597	7.968	3.961	0.598
Benzoic acid phonylester	2.87	3.26	7.671	3.776	0.577	7.689	3.788	0.578
Fenthion	3.31	3.75	13.068	7.137	0.854	13.100	7.157	0.855
Phenanthrene	4.09	4.35	12.302	6.660	0.823	12.322	6.672	0.824

tR1 = Retention time 1. Injection; tR2 = Retention time 2. Injection

k' = Capacity factor; Koc = Adsorption coefficient

*not used for determination of tR for sewage sludge

Table 5.4.1/2: Calibration Data of the Reference Items for Soil and Sewage Sludge

Parameters	Soil		Sewage sludge
	1.calibrationn	2.calibration	1.calibrationn	2.calibration
Slope	3.518	3.518	4.308	4.308
Intercept	0.7197	0.7162	0.4657	0.4614
r^2	0.9120	0.9120	0.9225	0.9225
r	0.9550	0.9550	0.9605	0.9605

r : Correlation Coefficient; r²: Coefficient of determination

Table 5.4.1/3: Retention Times, Capacity Factors (k') and Adsorption Coefficient (Koc) of ST 11 C 13 for Soil and sewage sludge

 

ST 11 C 13	tR (min)	K’	Log k’	logKoc soil 95% CI
				1.calibrationn	2.calibration
Soil
ST 11 C 13	5.352	2.333	0.3679	2.0 ± 0.1 1.7 to 2.4	2.0 ± 0.1 1.6 to 2.4
	5.352	2.333	0.3679
	5.351	2.332	0.3677
Mean	5.352	2.333	0.3678	2.0
Sewage sludge
ST 11 C 13	tR (min)	K’	Log k’	logKoc sewage sludge 95% CI
ST 11 C 13	5.352	2.333	0.3679	2.1 ± 0.2 1.5 to 2.6	2.0 ± 0.2 1.5 to 2.6
	5.352	2.333	0.3679
	5.351	2.332	0.3677
Mean	5.352	2.333	0.3678	2.1

 

tR = Retention time

CI = Confidence Interval

Validity Criteria

The validity criteria were fulfilled:

A signal-to-noise ratio > 3 was provided for NaNO3, reference and the test items.

The value of logKoc derived from repeated measurements made under identical conditions and using the same set of reference items fell within a range of ± 0.25 log units.

The column temperature during the measurement was kept in the range of 20-25 ± 1 °C and did not differ more than ± 1 °C.

Validity criteria fulfilled:

yes

Conclusions:

The adsorption coefficient log Koc of the test item ST 11 C 13 was determined to be 2.0 for soil and 2.1 for sewage sludge.

Executive summary:

The adsorption coefficient (Koc) for the test item ST 11 C 13 on soil and on sewage sludge using high performance liquid chromatography (HPLC) was estimated according to OECD 121 guideline with GLP compliance.

 

The test was performed temperature controlled, (23.6 °C, mean value) with a mobile phase consisting of 55 % methanol and 45 % HPLC water. A 550 mg/L sample of the test item ST 11 C 13 was analyzed threefold via HPLC on a cyanopropyl (CN-) column with DAD-detection.

 

Calibrations were performed using seven reference items for soil and six for sewage sludge with known logKoc values (given by the guidelines). The reference items were measured twice, once before and once after the measurement (double injection of one replicate) of the test item. Dead time of the HPLC-system was determined with sodium nitrate.

 

Two individual logKoc values for soil and for sewage sludge for the test item were derived under consideration of the first and second calibration. Finally a mean value for soil and for sewage sludge was calculated from, these individual logKoc values. Based on these data a logKoc of 2.0 for soil and a logKoc of 2.1 for sewage sludge were determined for ST 11 C 13.

 

ST 11 C 13	logKoc soil 95% CI		logKoc sewage sludge 95% CI
	1.calibrationn	2.calibration	1.calibrationn	2.calibration
	2.0 ± 0.1 1.7 to 2.4	2.0 ± 0.1 1.6 to 2.4	2.1 ± 0.2 1.5 to 2.6	2.0 ± 0.2 1.5 to 2.6
Mean	2.0		2.1

 

The adsorption coefficient log Koc of the test item ST 11 C 13 was determined to be 2.0 for soil and 2.1 for sewage sludge.

Description of key information

OECD Guideline 121, EU Method C.19, GLP, key study, validity 1:

log Koc = 2.0 for soil and 2.1 for sewage sludge

Koc = 100 for soil and 126 for sewage sludge

The substance is considered highly mobile in soils (according to the criteria developed by P.J. McCall et al., 1981).

Key value for chemical safety assessment

Koc at 20 °C:

126

Additional information

To assess the adsorption potential of the registered substance on soil and on sewage sludge, one key study is available.

This study (NOACK, 2015) was performed on the registered substance according to OECD Guideline 121 and EU Method C.19 (HPLC screening method) under GLP conditions. According to this study, the adsorption coefficient log Koc of the registered substance was determined at 2.0 for soil and 2.1 for sewage sludge. The results indicate that the substance is environmnetally high mobile in soils (according to P.J. McCall et al., 1981¹).

¹McCall P.J., Laskowski D.A., Swann R.L., and Dishburger H.J., (1981), “Measurement of sorption coefficients of organic chemicals and their use, in environmental fate analysis”, in Test Protocols for Environmental Fate and Movement of Toxicants. Proceedings of AOAC Symposium, AOAC,

Washington DC.

Mobility classification scheme:

Range of Koc	Mobility class
0 - 50	Very high
50 - 150	High
150 - 500	Medium
500 - 2000	Low
2000 - 5000	Slightly
> 5000	Immobile

[LogKoc: 2.1]