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Adsorption / desorption

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Reference
Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
16 November 2016 to 13 December 2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
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:
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. certificate)
Type of method:
HPLC estimation method
Media:
soil/sewage sludge
Radiolabelling:
no
Test temperature:
30 °C
Details on study design: HPLC method:
PREPARATION OF THE DEAD TIME SOLUTION
- The dead time was determined by measuring the retention time of formamide (purity quoted by supplier: 99.94%) at 615 mg/L in methanol.

PREPARATION OF REFERENCE STANDARD SOLUTIONS
- Solutions of reference standards were prepared in methanol as shown in Table 6 (below).

PREPARATION OF THE SAMPLE SOLUTION
- Test item (0.0536 g) was diluted to 100 mL with methanol:water (55:45 v/v) to give a concentration of 0.536 g/L.

DETERMINATION OF RETENTION TIME
- The sample, dead time and reference standard solutions were injected in duplicate using the High Performance Liquid Chromatography (HPLC) parameters shown in the table below.

CALCULATION OF CAPACITY FACTORS
- Capacity factors were determined using the equation k’ = (tr – t0) / t0 where k’ = capacity factor; tr = retention time (min); t0 = dead time (min)

CONSTRUCTION OF THE CALIBRATON CURVE
- A correlation of Log10 k' versus Log10 Koc of the reference items was plotted using linear regression (see Figure 1, attached).
- The capacity factors (k') for the reference items were calculated from the retention time data of the dead time and reference item solutions.
- The Log10 Koc values of the reference standards are those quoted in Method 121 of the OECD Guidelines for Testing of Chemicals, 22 January 2001.

ADSORPTION COEFFICIENT
- The Log10 Koc value was calculated using the equation Log10 Koc = (Log10 k’ – A) / B where Koc = adsorption coefficient; k’ = capacity factor; A = intercept of the calibration curve; B = slope of the calibration curve

MAJOR COMPUTERISED SYSTEMS
- EZChrom Elite version 3.3.2
Key result
Type:
log Koc
Value:
< 1.25 dimensionless
pH:
6.5
Temp.:
30 °C
Details on results (HPLC method):
RESULTS
- Typical chromatographs are presented in Appendix 2 (attached).
- The retention times of the dead time and the retention times, capacity factors and Log10 K0c values for the reference standards are shown in Table 7 (attached).
- The calibration curve from which the sample results were taken is presented in Figure 1 (attached).
- The retention times, capacity factors and Log10 Koc values for the sample are shown in Table 8 (below).

TABLE 8 – RETENTION TIMES, CAPACITY FACTOR AND LOG10 Koc VALUES FOR THE SAMPLE

Injection

Retention time (min)

Capacity factor (k’)

Log10 k’

Log10 Koc

1

1.999

1.04 x 10-2

-1.98

< 1.25

2

1.997

9.20 x 10-3

-2.04

< 1.25

Overall Log10 Koc: < 1.25

Adsorption coefficient: < 17.8

Validity criteria fulfilled:
yes
Conclusions:
The adsorption coefficient of the test item was determined to be < 17.8 with Log10 Koc < 1.25.
Executive summary:

GUIDELINE

The determination was carried out using the HPLC screening method, designed to be compatible with Method C.19 Adsorption Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 121 of the OECD Guidelines for Testing of Chemicals, 22 January 2001.

METHODS

The test utilised a High Performance Liquid Chromatograph. A commercially available cyanopropyl reverse phase HPLC column containing lipophilic and polar moieties was used. The dead time was determined by measuring the retention time of formamide (purity quoted by supplier: 99.94%) at 615 mg/L in methanol. Solutions of reference standards were prepared in methanol and the test item (0.0536 g) was diluted to 100 mL with methanol:water (55:45 v/v) to give a concentration of 0.536 g/L.

 

RESULTS

The adsorption coefficient of the test item was determined to be < 17.8 with Log10 Koc < 1.25.

Description of key information

The adsorption coefficient of the test item was determined to be < 17.8 with Log10 Koc < 1.25 (OECD 121 and EU Method C.19).

Key value for chemical safety assessment

Additional information

GUIDELINE

The determination was carried out using the HPLC screening method, designed to be compatible with Method C.19 Adsorption Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 121 of the OECD Guidelines for Testing of Chemicals, 22 January 2001.

METHODS

The test utilised a High Performance Liquid Chromatograph. A commercially available cyanopropyl reverse phase HPLC column containing lipophilic and polar moieties was used. The dead time was determined by measuring the retention time of formamide (purity quoted by supplier: 99.94%) at 615 mg/L in methanol. Solutions of reference standards were prepared in methanol and the test item (0.0536 g) was diluted to 100 mL with methanol:water (55:45 v/v) to give a concentration of 0.536 g/L.

 

RESULTS

The adsorption coefficient of the test item was determined to be < 17.8 with Log10 Koc < 1.25.