Calcium 4-chloro-2-(5-hydroxy-3-methyl-1-(3-sulfonatophenyl)pyrazol-4-ylazo)-5-methylbenzenesulfonate

Adsorption / desorption

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Administrative data

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Study performed according to OECD-Guideline and GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

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:

yes

Remarks:

The log Koc of 2-nitrobenzamide was taken from mean value of batch experiments on five soils adpoted from Gawlik & Muntau (1999)

GLP compliance:

yes

Type of method:

HPLC estimation method

Media:

other: soil and sewage sludge

Test material

Test material information

Constituent 1

Test material form:

solid: bulk

Radiolabelling:

no

Study design

Test temperature:

Mean value: 19.86 °C

HPLC method

Details on study design: HPLC method:

EQUIPMENT
- Apparatus:HPLC
- Type: HPLC system AGILENT 1100 consisting of

Auto sampler : Waters 712 WISP
Pump : Waters 712 WISP
Detector : Waters 2996 DAD
Software : Empower Pro (Build No: 1154), Waters

- Type, material and dimension of analytical column: HPLC column CC250/3 Nucleosil 100-5 CN, Macherey-Nagel
- Detection system: UV using DAD detector, 214.7 nm


MOBILE PHASES
- Type: acetonitrile : citrate-buffer / 55 : 45 (v/v); pH 3 and pH 6
- Experiments with additives carried out on separate columns: no
- Solutes for dissolving test and reference substances: acetonitrile and HPLC water to mobile phase ratio (test and reference items)
- Dilution: mobile phase


DETERMINATION OF DEAD TIME
- Method: by inert substances which are not retained by the column: NaNO3, 99.5 %


REFERENCE SUBSTANCES
- Identity: Reference Substances for Adsorption Coefficient in Soil and Sewage Sludge:
NO. 1 2-nitrobenzamide, CAS 610-15-1, 98.8 %, Aldrich
NO. 2 acetanilide, CAS 103-84-4, 99.9 %, Fluka
NO. 3 atrazine, CAS 1912-24-9, 98.0 %, Dr. Ehrenstorfer
NO. 4 triadimenol, CAS 55219-65-3, 98.0 %, Dr. Ehrenstorfer
NO. 5 pyrazophos, CAS 13457-18-6, 97.0 %, Dr. Ehrenstorfer
NO. 6 alpha-endosulfan, CAS 959-98-8, 97.0 %, Dr. Ehrenstorfer





DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 5 mg/L (nominal)
- Quantity of reference substances: 5 mg/L (nominal)
- Intervals of calibration: Set of reference substance - one before and one after the test item


REPETITIONS
- Number of determinations: Three injections


EVALUATION
- Calculation of capacity factors: k' = (tR-t0)/t0
- Determination of the log Koc value: By means of the adsorption coefficient values (KOC) and the corresponding capacity factors of the reference items a calibration graph of log k’ versus log KOC, soil and log k’ versus log KOC was plotted.

Batch equilibrium or other method

Analytical monitoring:

not required

Results and discussion

Adsorption coefficient

Adsorption coefficient 1

Type:

Koc

Value:

< 5.6

Adsorption coefficient 2

Type:

log Koc

Value:

< 0.75

Any other information on results incl. tables

Table 1: void time of the HPLC system

serial no.	t0[min] pH 6	t0[min] pH 3
1	2.579	2.805
2	2.514	2.786
3	2.507	2.780
mean ± SD	2.533 ± 0.040	2.790 ± 0.013

 

Table 2: calibration data of the reference substances (mean values)

reference substance	tR [min] pH 6	log KOCpH 6	tR [min] pH 3	log KOCpH 3
2-nitrobenzamide	3.496	0.75	3.558	0.75
acetanilide	3.663	1.25	3.709	1.25
atrazine	3.810	1.81	3.905	1.81
triadimenol	3.891	2.40	4.016	2.40
pyrazophos	4.139	3.65	4.314	3.65
Α-endosulphan	4.310	4.09	4.527	4.09

 

Table 3: retention times of the test item

serial no.	tR[min] pH 6	tR[min] pH 3
1	2.301	2.644
2	2.308	2.652
3	2.291	2.662
mean ± SD	2.300 ± 0.009	2.653 ± 0.009

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The estimated log Koc of the test item was determined to be < 0.75 corresponding to a Koc of < 5.6. According to the McCall classification scheme of soil mobility potential a Koc of < 5.6 would mean a very high mobility for Pigment Yellow 191 in soil.

Executive summary:

The adsorption coefficient (K_OC) on soil and on sewage sludge using high performance liquid chromatography (HPLC) was estimated according to OECD 121 and GLP.

The test was performed with a mobile phase acetonitrile : citrate-buffer / 55 : 45 (v/v) at pH 3 and pH 6. A 5 mg/L sample of the test item was analyzed threefold via HPLC on a cyanopropyl (CN-) column with PDA‑detection. Calibration was performed using 6 reference items with known values of log K_OC, 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. Dead time of the HPLC-system was determined threefold using 2 mg/L sodium nitrate.

Under test conditions the retention time of the test item was found to be 2.300 minutes at pH 6 and 2.653 at pH 3.

At test conditions the retention times of the test item correspond with the void time of the chromatographic system. This means, that the log K_OCof Pigment Yellow 191 was much lower than the log K_OCof the reference substance with the lowest log K_OC(2-nitrobenzamide: 0.75).

The estimated log K_OCof the test item was therefore determined to be < 0.75 corresponding to a K_OCof < 5.6. According to the McCall classification scheme of soil mobility potential a K_OCof < 5.6 would mean a very high mobility for Pigment Yellow 191 in soil.