Isooctyl mercaptoacetate

Adsorption / desorption

Administrative data

Endpoint:

adsorption / desorption: screening

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

March 03 to May 19 2008

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

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

Test material

Test material information

Constituent 1

Reference substance name:

2-ethylhexyl mercaptoacetate

EC Number:

231-626-4

EC Name:

2-ethylhexyl mercaptoacetate

Cas Number:

7659-86-1

Molecular formula:

C10H20O2S

IUPAC Name:

2-ethylhexyl sulfanylacetate

Constituent 2

Reference substance name:

2-ethylhexylmercaptoacetate

IUPAC Name:

2-ethylhexylmercaptoacetate

Details on test material:

TEST ITEM
Batch number: 12.11.07G
Purity: 99.77 %
Appearance: Colourless liquid
Solubility in water: Insoluble (20 °C)
Log P: 2.43
Density: 0.974 glcm3 (20°C)

Expiry date: 2009-11-12
Recommended storage: Cool and well ventilated place, room temperature, protected from moisture and Iight

Radiolabelling:

no

Study design

Test temperature:

21-23°C for soil
23.2-24.1°C for sediment

HPLC method

Details on study design: HPLC method:

Analyses of 2-Ethylhexyl thioglycolate were carried out by high performance liquid chromatography (HPLC) with an analytical column packed with cyanopropyl (CN-) solid phase. The test item was dissolved in mobile phase and injected into the HPLC where the test item interacted with the stationary phase while passing through the column. Detection was performed with a
DAD Detector.

HPLC-autosampler : WATERS 717 plus
Detection : 2996 Diode Array Detector, WATERS
HPLC-pump : WATERS 616 and 510, respectively
Software : Empower Pro (Build No: 1154), WATERS
Datalogger : VOLTCRAFT, K202
pH Meter : WTW 350i

Injection volume: 100 µL
Mobile phase: See test system
Column temperature: Room temperature
Flow: 0.7 mL/min
Wavelength: 210 nm for NaNO3 ; 215 nm for test item ; 234 nm for reference items

Run time: Maximum 45 min
Standard: Reference items were used as standards.
Calibration: The method was calibrated by determination of the retention times tr of six reference items for soil and for sewage sludge.

A threefold determination of the dead time to was performed with a solution of 5 mg/L NaNO3 in mobile phase. Mean value was calculated.
Determination of the retention times of eight reference items for soif and seven for sewage sludge.
Each reference item was analysed separately before and after analysis of the test item.
The retention time tR of the test item was determined with three injections.
Evaluation and plotting of each calibration graph log k' vs. log Koc of six reference items.

Results and discussion

Adsorption coefficient

Adsorption coefficient 1

Type:

Koc

Value:

1 809

Adsorption coefficient 2

Type:

log Koc

Value:

3.26

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

At the test conditions the adsorption coefficient of 2-Ethylhexyl thioglycolate was found to be log Koc soil = 3.26 and log Koc sewage sludge = 3.42. These values correspond to a Kocsoil = 1809 and Koc sewage sludge = 2642.

According to the McCall classification scheme of soil mobility potential a Koc of 1809 would mean that 2-Ethylhexyl thioglycolate is low mobile in soil.

Executive summary:

The adsorption coefficient (Koc) on soli and on sewage sludge using high performance liquid chromatography (HPLC) was estimated according to OECD 121 and Directive2001/159/EC, Method C.19 for the test item 2-Ethylhexyl thioglycolate (batch number: 12.11.07G).

The test was conducted with mobile phase of 55 % methanol and 45 % HPLC water. Samples of the test item 2-Ethylhexyl thioglycolate were analysed threefold via HPLC on a cyanopropyl (CN-) column with DAD - detection. Calibration was performed using six reference items with known values of log_Kocfor soil and six for sewage sludge, each with a nominal concentration of 5 mg/L. Analysis of the reference items were performed once before and after analysis of test item, respectively. The dead time of the HPLC-system was determined threefold using 5 mg/L sodium nitrate. At the test conditions the adsorption coefficient of 2-Ethylhexyl thioglycolate was found to be log Koc soil = 3.26 and log Koc sewage sludge = 3.42. These values correspond to a Kocsoil = 1809 and Koc sewage sludge = 2642. According to the McCall classification scheme of soil mobility potential a Koc of 1809 would mean that 2-Ethylhexyl thioglycolate is low mobile in soil.