α,α,α',α'-tetramethyl-m-xylene-α,α'-diol

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

- Title of report is not correct as no information on desorption is given. The subtitle (Estimation of the Adsorption coefficient….) displays the correct information. - Only five reference substances used instead of at least six as given in OECD 121 (sodium nitrate is used for the determination of the dead time) - Given concentration of reference substance phenanthrene stock solution is not accurate; however this does not have an impact on the final result. - Given concentration of test substance meta-Diisopropanolbenzene stock solution is not accurate; however this does not have an impact on the final result. - No information is given on duplicate analysis of the test substance and thus the repeatability cannot be judged. The reported Log Koc value of 1.36 is outside the reportable range of 1.5 – 5.0 as given in OECD 121. In that case the end result should be reported as Log Koc < 1.5 and Koc < 31.6. The reported results (Log Koc = 1.36 and Koc = 22.9) should be marked as extrapolated results.

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:

see Principles of method if other than guideline

Principles of method if other than guideline:

- Title of report is not correct as no information on desorption is given. The subtitle (Estimation of the Adsorption coefficient….) displays the correct information. - Only five reference substances used instead of at least six as given in OECD 121 (sodium nitrate is used for the determination of the dead time) - Given concentration of reference substance phenanthrene stock solution is not accurate; however this does not have an impact on the final result. - Given concentration of test substance meta-Diisopropanolbenzene stock solution is not accurate; however this does not have an impact on the final result. - No information is given on duplicate analysis of the test substance and thus the repeatability cannot be judged. The reported Log Koc value of 1.36 is outside the reportable range of 1.5 – 5.0 as given in OECD 121. In that case the end result should be reported as Log Koc < 1.5 and Koc < 31.6. The reported results (Log Koc = 1.36 and Koc = 22.9) should be marked as extrapolated results.

GLP compliance:

yes

Remarks:

GLP issued by State Environmental Protection Administration (SEPA) of the People’s Republic of China

Type of method:

HPLC estimation method

Radiolabelling:

no

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: 2695 HPLC (Waters, USA)
- Type:
- Type, material and dimension of analytical (guard) column: Waters Spherisob® 5 μm CN 4.6×250 mm (Waters, USA)
- Detection system: 2996 PDA (Waters, USA)

MOBILE PHASES
- Type: Methanol: Water = 50:50
- Experiments with additives carried out on separate columns: no
- pH:
- Solutes for dissolving test and reference substances: mobile phase

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

REFERENCE SUBSTANCES
- Identity:
Phenol (C6H6O, MW: 94.11): Reference substances, Laboratories of Dr. Ehrenstorfer;
Atrazine (C8H14ClN5, MW: 215.69): Reference substances, Laboratories of Dr. Ehrenstorfer;
Linuron (C9H10Cl2N2O2, MW: 249.1): Reference substances, Laboratories of Dr.Ehrenstorfer;
Naphthalene (C10H18, MW: 138.25): Reference substances, Laboratories of Dr. Ehrenstorfer;
Phenanthrene (C14H10, MW: 178.22): Reference substances, Laboratories of Dr. Ehrenstorfer.

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 5.0, 10.0 and 20 mg/L
- Quantity of reference substances: 10mg/L
- Intervals of calibration:

REPETITIONS
- Number of determinations: 2

EVALUATION
- Calculation of capacity factors k':
The capacity factors k’ will be calculated from the dead time to and retention times tR of the selected reference substances according to the following equation:
k' = (tR - t0)/t0
Where:
tR: HPLC retention time of test and reference substance (minutes)
t0: HPLC dead time (minutes)

- Calculation of retention times:
- Determination of the log Koc value:
The adsorption coefficient (Koc) is deduced from the capacity factor ( k’) using a calibration plot of log k’ versus log Koc of the selected reference compound.

Type:

Koc

Value:

22.9

Remarks on result:

other: Log Koc = 1.36

Details on results (HPLC method):

- Retention times of reference substances used for calibration:
Substance Dead time Retention time
t0 (min) tR (min)
Sodium nitrate 1.862
Phenol 3.378
Atrazine 3.630
Linuron 4.000
Phenanthrene 4.457
DDT 5.715
- Details of fitted regression line (log k' vs. log Koc):
Y =6.6439 x +1.9696, r2 =0.9811, where Y was log Koc and x was log k’
- Graph of regression line attached
- Average retention data for test substance: 3.369 min

Validity criteria fulfilled:

not applicable

Conclusions:

The results showed that Koc value of meta-Diisopropanolbenzene was 22.9. Therefore, the test substance meta-Diisopropanolbenzene has low adsorbability, according to “The guidelines for the hazard evaluation of new chemical substances (SEPA HJ/T 154-2004)”.

Executive summary:

Estimation of the Adsorption Coefficient (K_oc) on Soil and on Sewage Sludge of meta-Diisopropanolbenzene using High Performance Liquid Chromatography (HPLC) was conducted according to “The guidelines for the testing of chemicals” (HJ/T 153-2004), “The guidelines for the testing of chemicals” (SEPA,: China Environmental Sciences Press. 2004) and OECD Procedure 121, “Estimation of the Adsorption Coefficient (K_oc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC)” etc. The results showed that K_ocvalue of meta-Diisopropanolbenzene was 22.9. Therefore, the test substance meta-Diisopropanolbenzene has low adsorbability, according to “The guidelines for the hazard evaluation of new chemical substances (SEPA HJ/T 154-2004)”.

Description of key information

The reported Log Koc value of 1.36 is outside the reportable range of 1.5 – 5.0 as given in OECD 121. In that case the end result should be reported as Log Koc < 1.5 and Koc < 31.6. The reported results (Log Koc = 1.36 and Koc = 22.9) should be marked as extrapolated results.