Reaction products of 2,5-dimercapto-1,3,4-thiadiazole, sodium salt, with 1-octanethiol and hydrogen peroxide

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:

21 September 2017 to 7 March 2018

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))

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))

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Media:

soil

Specific details on test material used for the study:

-Purity: >99% (UVCB)
-Description: Amber Clear Liquid

Test temperature:

30 °C (Column temperature)

Details on study design: HPLC method:

Preparation of sample solution - Test Substance Stock

A 10 mg/mL of the test material primary stock solution was prepared by bringing 0.0992 g (tested as 100%) of the test stubstance to a final volume of 9.92 mL with methanol.

This stock solution was stored in a freezer in a clear glass bottle with Teflon-lined cap. A 1 mg/mL secondary stock solution was prepared by bringing 1 mL of the 10 mg/mL primary stock solution to a volume of 10 mL with methanol.

Mobile phase flow rate: 1.0 mL/min
UV wavelength: 210 and 240 nm

Key result

Sample No.:

#1

Type:

log Koc

Value:

ca. 7.62 dimensionless

Matrix:

soil

Key result

Sample No.:

#2

Type:

log Koc

Value:

ca. 8.23 dimensionless

Matrix:

soil

Key result

Sample No.:

#3

Type:

log Koc

Value:

ca. 8.71 dimensionless

Matrix:

soil

Key result

Sample No.:

#4

Type:

log Koc

Value:

ca. 9.25 dimensionless

Matrix:

soil

Key result

Sample No.:

#1

Type:

log Koc

Value:

ca. 7.57 dimensionless

Matrix:

sludge

Key result

Sample No.:

#2

Type:

log Koc

Value:

ca. 8.16 dimensionless

Matrix:

sludge

Key result

Sample No.:

#3

Type:

log Koc

Value:

ca. 8.62 dimensionless

Matrix:

sludge

Key result

Sample No.:

#4

Type:

log Koc

Value:

ca. 9.14 dimensionless

Matrix:

sludge

Details on results (HPLC method):

The log Koc values of the test material in soil and sludge ranged from 7.62 to 9.25 and from 7.57 to 9.14, respectively.

The mean retention times of the four major components of the test material approximately 25.9, 34.5, 43.5, and 56.5 minutes. The mean log Koc values determined for these components for soil and sludge ranged from 7.62 (Koc 41,668,651) to 9.24 (Koc 1,731,122,699) and from 7.57 (Koc 37,197,330) to 9.13 (Koc ,1,343,255,426) respectively, which were calculated by extrapolation from the calibration curves. The duplicate log Koc values for each major constituent in reaction products of 2,5-dimercapto-1,3,4-thiadiazole, sodium salt, with 1-octanethiol and hydrogen peroxide were considered acceptable since they fell within a range of ± 0.25 log units.

Validity criteria fulfilled:

yes

Conclusions:

The log Koc values of the test material in soil and sludge ranged from 7.62 to 9.25 and from 7.57 to 9.14, respectively.

Executive summary:

The objective of this study was to determine the adsorption coefficient (Koc) for the test material. The study has been performed to the standardized guideline OECD 121, under GLP conditions.

 

The adsorption distribution coefficient (Kd) is the ratio of the concentration of the test substance in the soil (Cs) and the concentration of the test substance in the aqueous phase (Caq) at the point of equilibrium. The adsorption coefficient (Koc) is the adsorption distribution coefficient (Kd) normalized with the organic carbon content of the soil (foc). A series of reference substances with well-characterized partition coefficients were injected onto the analytical column which was then followed by an injection of the test substance. The retention of each reference substance injected onto such a column is proportional to the adsorption coefficient of that substance, with water-soluble chemicals eluting first and oil-soluble chemicals last. The adsorption coefficient of the test substance was derived from the retention factor (k), using a calibration plot of log k versus log Koc of the reference substances.

 

The mean retention times of the four major components comprising the test material were approximately 25.9, 34.5, 43.5, and 56.5 minutes.

 

The mean log Koc values determined for these components for soil and sludge ranged from 7.62 (Koc 41,668,651) to 9.24 (Koc 1,731,122,699) and from 7.57 (Koc 37,197,330) to 9.13 (Koc ,1,343,255,426) respectively, which were calculated by extrapolation from the calibration curves. The duplicate log Koc values for each major constituent in the test material were considered acceptable since they fell within a range of ± 0.25 log units.

Description of key information

The objective of this study was to determine the adsorption coefficient (Koc) for the test material. The study has been performed to the standardized guideline OECD 121, under GLP conditions. The mean retention times of the four major components comprising the test material were approximately 25.9, 34.5, 43.5, and 56.5 minutes. The mean log Koc values determined for these components for soil and sludge ranged from 7.62 (Koc 41,668,651) to 9.24 (Koc 1,731,122,699) and from 7.57 (Koc 37,197,330) to 9.13 (Koc ,1,343,255,426) respectively, which were calculated by extrapolation from the calibration curves. The duplicate log Koc values for each major constituent in the test material were considered acceptable since they fell within a range of ± 0.25 log units.