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EC number: 613-953-8 | CAS number: 66603-10-9
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
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- Endpoint summary
- Stability
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- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
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- Toxicity to other aquatic organisms
- Sediment toxicity
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- Toxicokinetics, metabolism and distribution
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- Specific investigations
- Exposure related observations in humans
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- Additional toxicological data
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Adsorption / desorption
Administrative data
- Endpoint:
- adsorption / desorption: screening
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- Experiments: 28.11.2005 - 12/13.12.2005
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
Data source
Reference
- Reference Type:
- study report
- Title:
- Unnamed
- Year:
- 2 006
- Report date:
- 2006
Materials and methods
Test guideline
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 106 (Adsorption - Desorption Using a Batch Equilibrium Method)
- Deviations:
- no
- GLP compliance:
- yes (incl. QA statement)
- Type of method:
- batch equilibrium method
- Media:
- soil
Test material
- Reference substance name:
- Cyclohexylhydroxydiazene 1-oxide, potassium salt
- EC Number:
- 613-953-8
- Cas Number:
- 66603-10-9
- Molecular formula:
- C6H11KN2O2
- IUPAC Name:
- Cyclohexylhydroxydiazene 1-oxide, potassium salt
- Test material form:
- solid: particulate/powder
- Details on test material:
- Test item: (N-Cyclohexyl-diazeniumdioxy)-potassium
IUPAC name: Cyclohexylhydroxydiazene 1-oxide, potassium salt
Chemical name: Cyclohexylhydroxydiazene 1-oxide, potassium salt; synonyma: (N-Cyclohexyl-diazeniumdioxy)-potassium, K-HDO, K-NCH, Xyligen K powder, Xyligen K
Molecular formula: C6 H11 K N2 O2
Molecular mass: 182.27
Constituent 1
- Specific details on test material used for the study:
- See table below
- Radiolabelling:
- no
Study design
- Test temperature:
- Mean room temperature of 22.94 ± 0.46 °C.
HPLC method
- Details on study design: HPLC method:
- The HPLC - Instrument parameters and the chromatographic conditions are given in the table below.
1.1. HPLC - MEASUREMENTS:
1.1. Calibration:
The calibration of the analytical method was performed in three calibration ranges:
High calibration range: 10 - 130 µg/mL
Mid calibration range: 1 - 13.0 µg/mL
Low calibration range: 0.1 - 1.3 µg/mL
All calibration lines were measured with 7 calibration points in duplicate. The calibration function and the correlation coefficient were calculated.
To eliminate some variations in detector response during the test, three recalibration standards with concentrations corresponding to the calibration ranges were analyzed before and after each sample group.
All measured concentrations were multiplied with the corresponding recalibration factor. The applied recalibration factors were in the range of 0.88 to 1.050, i.e. the change in detector response was less or equal 20 % over the test duration of about 5 weeks.
For the measurements of Tier 3 desorption complete new calibration lines were measured.
1.2. System validation:
To determine the system suitability a system validation procedure was developed. The system validation test contained:
Injection test: Injection volume of the auto sampler varied from 1 to 100 µl
Linearity test 1: Standard solutions I - IV (concentration range 107.9 - 0.1079 µg/mL)
Linearity test 2: Test item solutions I - III (concentration range 100.5 - 1.005 µg/mL)
Reproducibility: 7-fold injections of standards (calibration range High, Mid, Low)
1.3. Sample measurement:
The samples were measured with the HPLC-conditions described in the table "HPLC - Instrument parameters". A set of recalibration standards, which include the three calibration ranges, were measured before and after a sample set.
Batch equilibrium or other method
- Analytical monitoring:
- yes
- Details on sampling:
- See above
- Details on matrix:
- COLLECTION AND STORAGE
Soils were derived from LUFA "Landwirtschaftliche Untersuchungs- und Forschungsanstalt", Agricultural Investigation and Development Institute, Speyer, Germany
PROPERTIES
see table "Soil information" - Details on test conditions:
- TEST CONDITIONS
The adsorption /desorption characteristics of K-HDO were investigated according to the OECD Guideline No. 106 (OECD Guideline for Testing of Chemicals "Determination of Soil Adsorption/Desorption, using a Batch Equilibrium Method" , 2000). The laboratory study was performed with five certified soils.
The test comprises three tiers. The tier 1 is the preliminary study, the tier 2 is the screening test (in 5 soils) and the tier 3 is the determination of Freundlich adsorption isotherms or the study of desorption by means of desorption kinetics/Freundlich desorption isotherms, as appropriate.
TEST SYSTEM
- Water filtered (i.e. yes/no; type of size of filter used, if any):
- Amount of soil per treatment: To prepare the blank recovery samples, 2 x 2.0 g soil (calculated as dry matter) was fortified with 1.0 mL of the blank solution, mixed well and equilibrated for 2 hours without shaking.
To prepare the high range recovery samples, 2.0 g soil (calculated as dry matter) was fortified with 1.0 mL of the test item stock solution, mixed well and equilibrated for 2 hours without shaking.
To prepare the low range recovery samples, 2.0 g soil (calculated as dry matter) was fortified with 0.1 mL of the test item stock solution and 0.9 ml of 0.01 m CaCl2 solution, mixed well and equilibrated for 2 hours without shaking.
- Measuring equipment:
- Test performed in closed vessels due to significant volatility of test substance: no
- Test performed in open system: yes
- Method of preparation of test solution: see table below
Results and discussion
Adsorption coefficient
- Key result
- Type:
- other: Freundlich adsorption constants KFads for all soils
- Value:
- >= 20.5 dimensionless
Results: Batch equilibrium or other method
- Adsorption and desorption constants:
- The determined Freundlich adsorption constants KFads for all soils were between 20.5 (soil Bruch West) and 223.8 (Soil LUFA 2.2), the respective organic carbon content normalized values (KF,oc ads) between 10606 and 805.
The determined Freundlich desorption constant KFdes for all soils was between 27.0 (soil Bruch West) and 343.8 (soil LUFA 2.2). - Recovery of test material:
- The recovery rate of CaCl2-soluble K-HDO was determined to be 95.6 % for the 0.1 mg/L level and 100.8 % for the 10 mg/L level.
The recovery rate of Methanol/Eluent-extract soluble K-HDO was determined to be 80.5 % for the 50 mg/kg concentration level and 89.1 % for the 500 mg/kg level.
All determined recovery rates met the validation criteria requested to be between 70 and 110 %.
- Transformation products:
- no
- Details on results (Batch equilibrium method):
- See tables below
- Statistics:
- Mean, standard deviation and relative standard deviation were calculated.
Any other information on results incl. tables
LoD and LoQ of the determination of K-HDO:
|
CaCl2- Extract |
CaCl2- Extract |
Methanol / Eluent - Extract* |
Methanol / Eluent- Extract |
|
mg/L extract |
mg/kg soil |
mg/L extract |
mg/kg soil |
Limit of detection LoD |
0.05 |
1.2 |
0.05 |
0.6 |
Limit of quantification LoD |
0.1 |
10 |
4 |
50 |
Results of preliminary test:
Test substance |
K-HDO |
Sample purity |
100 % as (N-Cyclohexyldiazeniumdioxy)-potassium monohydrate |
Weighed soil |
2 g soil |
Volume of CaCl2solution |
49-50 mL CaCl2extraction solution |
Nominal concentration of a.s. final solution |
Analytically verified concentrations used |
Analytical concentration final of a.s. solution |
Was determined for each solution and used for calculation |
Concentration of the test solution (show calculation) |
Analytically verified concentrations used |
Details of the analytical method used: |
Determination of the K-HDO content was performed by analysis of K-HDO using HPLC and UV/VIS detection. The method was calibrated in the range from 0.1-130 µg/mL K-HDO and validated. |
Method |
HPLC-UV/VIS |
Recovery rate (CaCl2-soluble K-HDO recovery rate) |
95.6 % at 0.1 mg/L level 100.8 % at the 10 mg/L level |
Detection limit |
0.05 mg/L CaCl2extract |
Results of test - adsorption:
|
Bruch West |
LUFA 2.1 |
LUFA 2.2 |
LUFA 2.3 |
LUFA 6S |
Concentration of test material [mg/L] |
0.8-201 |
0.8-201 |
0.8-201 |
0.8-201 |
0.8-201 |
After contact of 24 hours with soil |
0.387-175.8 |
0.176-126 |
0.079-35 |
0.28-146.9 |
0.142-124.6 |
Correction for blank with soil |
0 |
0 |
0 |
0 |
0 |
Correction for blank without soil |
0 |
0 |
0 |
0 |
0 |
Final corrected concentration [mg/L] |
0.387-175.8 |
0.176-126 |
0.079-35 |
0.28-146.9 |
0.142-124.6 |
Initial concentration of test solution [mg/L] |
0.8-201 |
0.8-201 |
0.8-201 |
0.8-201 |
0.8-201 |
Decrease in concentration [mg/L] |
0.413-26.2 |
0.624-75 |
0.72-166 |
0.52-54.1 |
0.658-76.4 |
Quantity adsorbed [mg] |
20.8-1259.6 |
31.4-3750.8 |
36.2-8300 |
26-2705 |
33.1-3819 |
Quantity of soil [g of oven-dried equivalent] |
2 |
2 |
2 |
2 |
2 |
Quantity adsorbed [mg] per gram of soil |
10.4-628.5 |
15.7-1872.8 |
18.1-4142.5 |
13-1351 |
16.5-1909 |
Test material adsorbed [%] |
51.8-12.5 |
78.1-37.1 |
90.1-82.6 |
64.8-26.9 |
82.3-38 |
Temperature [°C] |
22.9 |
22.9 |
22.9 |
22.9 |
22.9 |
Distribution coefficient at adsorption equilibrium Kd |
26.88-3.58 |
89.4-14.9 |
289-118.2 |
45.9-9.2 |
149-15.3 |
Organic carbon normalized adsorption coefficient |
1058-140.7 |
14186-2358.7 |
10796-5602 |
4499-902 |
6339-822 |
Freundlich adsorption coefficient |
20.5 |
66.3 |
223.8 |
38.1 |
79.8 |
Organic carbon normalized Freundlich adsorption coefficient |
805 |
10518 |
10606 |
3739 |
4360 |
PH-value of the aqueous phase at adsorption equilibrium |
7.2-7.4 |
5.9-6.7 |
5.5-6.3 |
6.75-7 |
6.9-7.2 |
Results of test - desorption:
|
Bruch West |
LUFA 2.1 |
LUFA 2.2 |
LUFA 2.3 |
LUFA 6S |
Temperature [°C] |
22.1 |
22.1 |
22.1 |
22.1 |
22.1 |
Evaluated concentration range [µg/g] |
20-5015 |
20-5015 |
20-5015 |
20-5015 |
20-5015 |
Freundlich desorption coefficient |
27 |
103.3 |
343.8 |
53.7 |
93.5 |
Organic carbon normalized Freundlich desorption coefficient |
1064 |
15472 |
16293 |
5261 |
5112 |
[%] of desorbed test material |
34-55 |
17-24 |
4-9 |
23-39 |
14-35 |
Correlation coefficient R² |
0.964 |
0.998 |
0.976 |
0.972 |
0.985 |
Applicant's summary and conclusion
- Validity criteria fulfilled:
- yes
- Conclusions:
- The adsorption in all soils exceeded 25 %.
The recovery rates of the CaCl2-soluble K-HDO recovery test were calculated to be 95.6 % for the 0.1 mg/I concentration level and 100.8%for the 10 mg/I level.
The recovery rates of the Methanol/Eluent-extraction of K-HDO from soil were calculated to be 80.5 % for the 50 mg/kg concentration level and 89.1% for the 500 mg/kg level.
The recovery rate of the mass balance experiment was calculated to be 90.2%.The mass balance, considering the aqueous and the soil phase (by extraction with methanol/eluent) was> 90%, indicating the stability of the compound during the test.
Taking the adsorption behaviour of the test item into account, the adsorption equilibration time was 24 hours. Since adsorption may continue by longer agitation due to diffusion, slow degradation or the formation of bound residues, the obtained adsorption data represent worst case values. The organic carbon normalized Freundlich adsorption coefficient KF,ocadsvalues are considerable and in the range from 805 to 10606.
The maximal desorption was reached after 8 hours of agitation for all soils.The resulting organic carbon normalized Freundlich desorption coefficient KF,ocdeswere in the range from 1064 to 16394 and therefore significantly 1.4 fold higher than the corresponding adsorption values, indicating irreversible adsorption - Executive summary:
The adsorption /desorption characteristics of K-HDO were investigated according to the OECDGuideline No. 106 (OECD Guideline for Testing of Chemicals "Determination of Soil Adsorption/Desorption, using a Batch Equilibrium Method" , 2000).
The laboratory study was performed with five certified soils.
1. An analytical method was adapted and validated to determine K-HDO in extraction solvents from an adsorption/desorption study. The validation parameters confirm the suitability of the method for the adsorption/desorption study.
2. The performance of the study shows different adsorption behaviours of K-HDO towards the soils used with the present concentrations. The soil LUF A 2.2 shows the strongest adsorption of all the investigated soils, followed by the soils LUF A 2.1, and LUFA 6S. The adsorption of the soils Bruch West and LUFA 2.3 is lower.
3. The adsorption equilibrium time was reached at 24 h. After this time, only a slight adsorption increase was observed so that the adsorption values obtained represent worst case values.
4. The determined Freundlich adsorption constants KFads for all soils were between 20.5 (soil Bruch West) and 223.8 (Soil LUFA 2.2), the respective organic carbon content normalized values (KF,oc ads) between 10606 and 805.
5. The desorption equilibrium time was reached at 8 h.
6. The desorption behaviour of K-HDO corresponds to the adsorption on the soils.
7. The determined Freundlich desorption constant KFdes for all soils was between 27.0 (soil Bruch West) and 343.8 (soil LUFA 2.2).
8. For all the soils the organic carbon normalized Freundlich adsorption constant KF,ocads and the organic carbon normalized Freundlich desorption constant KF,ocdes were calculated.
9. The Freundlich desorption coefficient KFdes is higher than the corresponding Freundlich adsorption coefficient KFads by the reversibility factor 1.4 (averaged over all the soils). The test item K-HDO is practically irreversibly adsorbed on the soils.
The parameters of Freundlich adsorption/desorption equation were summarized in the following table:
Parameter
Soil
Bruch West
LUFA 2.1
LUFA 2.2
LUFA 2.3
LUFA 6S
Mean
Freundlich adsorption coefficient
KFads
20.5
66.3
223.8
38.1
79.8
85.7
exponent
n
1.498
1.404
1.105
1.373
1.555
inverse exponent
1/n
0.6677
0.7138
0.9100
0.7281
0.6433
organic carbon normalized Freundlich adsorption coefficient
KF,OCads
805
10518
10606
3739
4360
6007
Freundlich desorption coefficient
KFdes
27.0
97.5
343.8
53.7
93.5
123.1
exponent
n
1.048
1.059
0.959
0.989
1.257
inverse exponent
1/n
0.9542
0.9445
1.0434
1.0113
0.7955
organic carbon normalized Freundlich desorption coefficient
KF,OCdes
1064.2
15472.1
16292.6
5261.1
5111.9
8640
Reversibility factor
KFdes/KFa ds
1.321
1.171
1.536
1.407
1.172
1.381
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