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Reference
Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
29 May, 2020
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
GLP compliance:
yes (incl. QA statement)
Type of method:
HPLC estimation method
Media:
other: HPLC method
Specific details on test material used for the study:
Physical appearance : Black powder
Purity as per CoA : 99.1 % (w/w)
Batch No. : 1404301
Manufactured date : 20 September 2014
Expiry date : 08 April 2024
Density : 1.2654 g/cm3
pH : 5.0 (susp. of 2 % (w/w) in water)
Recommended storage condition : Ambient (+15 to +25 °C)
Radiolabelling:
no
Details on study design: HPLC method:
EQUIPMENT
- Apparatus: High Performance Liquid Chromatograph (HPLC) equipped with DAD, auto sampler and PC based data system.
- HPLC column: Inertsil CN, 250mm long, 4.6mm i.d., 5 µm particle size
- Column Thermostat: 25 °C

MOBILE PHASES: Milli-Q Water: Acetonitrile (45:55, v/v)
Flow Rate: 1.0 mL/min.
Detector wave length: 254 nm
Injection Volume: 10 µL
Runtime: 20 minutes

• All the HPLC parameters were remain constant throughout the analysis.
• Formamide solution of known concentration was injected in duplicate to determine the dead time based on its retention time.
• All the selected reference substance solutions were analyzed in duplicate separately and analyzed with the test item solution in triplicate and to determine the retention time for the test item and all the reference substances.
• The calibration mixture (mixture of all the reference substance, details will be given in raw data) was injected before and after the sample injections to check the instrument performance.

DETERMINATION OF DEAD TIME
- Method: The dead time (t0) was determined based on retention time of inert substances (formamide), which was not retained on the column. Measurement was done in duplicate.

REFERENCE SUBSTANCES
1. R.S Name: Acetanilide
Purity: >99.9%
Source: Sigma Aldrich
Batch No.: STBH7145
2. R.S Name: Formamide
Purity: 99.7 %
Source: Spectrochem Pvt. Ltd.
Batch No.: B300593

3. R.S Name: Methyl Benzoate
Purity: >99.9 %
Source: Aldrich Chemistry
Lot No.: STBF7480V

4. R.S Name: Benzyl Benzoate
Purity: 99.9 %
Source: Sigma Aldrich
Lot No.: MKCC3882

5. R.S Name: Diphenylamine
Purity: 99.0 %
Source: SDFCL, Mumbai
Batch No: D15A/0414/1509/13

6. R.S Name: Phenanthrene
Purity: 99.5%
Source: Sigma Aldrich
Batch No.: MKCG6676

7. R.S Name: Benzo [a] pyrene
Purity: 100%
Source: Sigma Life Science
Batch No.: SLBV8459


DETERMINATION OF RETENTION TIMES
The test item in triplicate and reference substances duplicate was injected separately in quantities as small as possible and their retention time was determined (tR).

REPETITIONS
- Number of determinations: The samples were prepared and were analyzed in triplicate for test item FAT 36038/J and in duplicate for all the reference and inert substances by HPLC.

EVALUATION
- Calculation of capacity factors k': Capacity factor for each of the substance was calculated as
k' = (tR-t0)/t0
where,
tR - Retention time of test and reference substances (min.)
t0 - Dead time (min.)

- Calculation of retention times: The test item in triplicate and reference substances duplicate was injected separately in quantities as small as possible and their retention time was determined (tR).
- Calibration Graph
Calibration graph of log k versus log KOC for the reference substances was plotted by taking log k' on the X axis and log KOC on the Y axis.
- Adsorption Coefficient of the Test Item
From the calibration graph, values of ‘a’ (intercept), ‘b’ (slope) and ‘r' (correlation coefficient) was obtained. By substituting a, b values, and log k' values of the test item in the below equation, partition coefficient was obtained.
log KOC = a + b × log k'

- Quality Criteria
The value of log KOC derived from repeated measurements (in duplicate) made under identical conditions and using the same set of reference substances should fall within 0.25 log units.
Sample No.:
#1
Type:
Koc
Value:
15 488.17
Temp.:
20 °C
Remarks on result:
other: pH not specified

The experimental method exercised in this study used HPLC to determine KOC. This was accomplished by using a cyanopropyl column consisting of stationary phase with both non-polar and polar sites. The interaction of the non-polar and polar sites on the column with polar and non-polar groups on the molecule is similar to how the molecule would act in the presence of organic matter in soil or sewage sludge. Because of this similarity, we are able to relate the retention time on a column with the adsorption coefficient on organic matter.


Analysis of the inert substance (Formamide) provided a dead time analysis (t0) of 3.8440 min. The linear regression (Figure 11) of reported log KOC values and measured retention times log k′ (capacity factor) of the calibration standards gave a correlation coefficient of 0.9683 and an equation describing the line of:


Log KOC= 4.3763 + 4.4042 (log k′)


The obtained correlation coefficient was in acceptable range, i.e., above 0.95. Using the regression, log KOC values of the test item FAT 36038/J was calculated allowing the adsorption coefficient to be determined. The obtained adsorption coefficient (KOC) of the test item FAT 36038/J was 15488.17 and the respective log KOCvalue was 4.19. Similarly, the log KOC values of the test item FAT 36038/J was calculated from the results obtained from the repeatability test and thelog KOC value (4.28) thus obtained was within 0.25 log units as compared to the first determination mentioned above.

Validity criteria fulfilled:
yes
Conclusions:
The obtained adsorption coefficient (KOC) of FAT 36038/J was 15488.17 and the respective log KOC value was 4.19.
Executive summary:

The adsorption coefficient (Koc) of the test item FAT 36038/J was determined by HPLC method in accordance with OECD 121. The experimental method exercised in this study used HPLC to determine KOC. This was accomplished by using a cyanopropyl column consisting of stationary phase with both non-polar and polar sites. The interaction of the non-polar and polar sites on the column with polar and non-polar groups on the molecule is similar to how the molecule would act in the presence of organic matter in soil or sewage sludge. Because of this similarity, the retention time on a column can be realted with the adsorption coefficient on organic matter. Analysis of the inert substance (Formamide) provided a dead time analysis (t0) of 3.8440 min. The linear regression of reported log KOC values and measured retention times log k′ (capacity factor) of the calibration standards gave a correlation coefficient of 0.9683 and an equation describing the line of:


Log KOC= 4.3763 + 4.4042 (log k′)


The obtained correlation coefficient was in acceptable range, i.e.,above 0.95.


Using the regression, log KOCvalues of the test item FAT 36038/J was calculated allowing the adsorption coefficient to be determined. The obtained adsorption coefficient (KOC) of the test item FAT 36038/J was 15488.17 and the respective log KOC value was 4.19. Similarly, the log KOC values of the test item FAT 36038/J was calculated from the results obtained from the repeatability test and the log KOCvalue (4.28) thus obtained was within 0.25 log units.

Description of key information

The obtained adsorption coefficient (KOC) of FAT 36038/J TE was 15488.17 and the respective log KOCvalue was 4.19.

Key value for chemical safety assessment

Koc at 20 °C:
15 488.17

Additional information

The adsorption coefficient (Koc) of the test item, FAT 36038/J was determined by HPLC method in accordance with OECD 121.The experimental method exercised in this study used HPLC to determine KOC. This was accomplished by using a cyanopropyl column consisting of stationary phase with both non-polar and polar sites. The interaction of the non-polar and polar sites on the column with polar and non-polar groups on the molecule is similar to how the molecule would act in the presence of organic matter in soil or sewage sludge. Because of this similarity, the retention time on a column can be realted with the adsorption coefficient on organic matter. Analysis of the inert substance (Formamide) provided a dead time analysis (t0) of 3.8440 min. The linear regression of reported log KOC values and measured retention times log k′ (capacity factor) of the calibration standards gave a correlation coefficient of 0.9683 and an equation describing the line of:


Log KOC= 4.3763 + 4.4042 (log k′)


The obtained correlation coefficient was in acceptable range, i.e.,above 0.95.


Using the regression, log KOC values of the test item FAT 36038/J was calculated allowing the adsorption coefficient to be determined. The obtained adsorption coefficient (KOC) of the test item FAT 36038/J was 15488.17 and the respective log KOC value was 4.19. Similarly, the log KOC values of the test item FAT 36038/J was calculated from the results obtained from the repeatability test and the log KOC value (4.28) thus obtained was within 0.25 log units.