4,4'-cyclohexylidenedi-o-cresol

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Deviations:

no

GLP compliance:

yes

Radiolabelling:

no

Analytical monitoring:

yes

Buffers:

Buffers were prepared by placing approximately 900 mL of deionised water in a graduated cylinder with the following amounts of chemicals and then bringing the volume to 1000 mL:
pH 4.0: 10.2 g hydrogen potassium phthalate + 4.0 mL 0.1 M NaOH
pH 7.0: 6.8 g KH2PO4 + 296.5 mL 0.1 M NaOH
pH 9.0: 3.1 g boric acid + 213 mL 0.1 M NaOH
The solutions were adjusted to the exact pH by addition of 5 M NaOH. The buffer solutions were filter-sterilised before use.

Details on test conditions:

Approximately 1.5 mg of DMBPC was added to each liter of buffer and stirred for three days. After 3 days, insoluble particles were still visible. Sixty mL of buffer solution was removed and filtered through a 0.7 micron glass fiber filter into a flask. No particles were visible in the filtrate. The 0.7 micron glass fiber filter technique was previously tested with a much more concentrated DMBPC/water slurry. HPLC analysis gave a DMBPC concentration of 1.1 mg/L, which is at the solubility of DMBPC. This indicated that there were no insoluble particles present in the filtrate.

Twenty five mL of the filtrate from the buffer solutions was dispensed into each of two 50 mL glass bottles and capped with Teflon-lined caps. All glassware and utensils used in this procedure were sterilised in an autoclave. Two samples were taken from each bottle and put into HPLC vials for immediate t=0 analysis. The bottles were taped on their sides to a rack in a shaker incubator set at 50 °C and gently agitated for five days. Samples were then removed from the bottles for immediate t=5 days analysis.

Duration:

5 d

pH:

4

Temp.:

50 °C

Initial conc. measured:

345 µg/L

Duration:

5 d

pH:

7

Temp.:

50 °C

Initial conc. measured:

345 µg/L

Duration:

5 d

pH:

9

Temp.:

50 °C

Initial conc. measured:

345 µg/L

Number of replicates:

2

Positive controls:

not specified

Negative controls:

not specified

Preliminary study:

There was no loss of DMBPC over the 5 days at 50 °C. The slight increase in recovery of the pH 4 and pH 7 samples at day 5 is unexplained. Purity checks by examination of the UV scans through the DMBPC peaks showed no secondary peak contamination.

Test performance:

The UV spectrum of DMBPC, as taken from the diode array detector, showed a partial peak at 230 nm which was used for quantification. The limit of detection of DMBPC was near 8 µg/L based on a signal-to-noise ratio of approximately five.

The DMBPC calibration curve showed linear relationships with correlation coefficients not less than 0.99988, indicating acceptable method precision for the analysis of DMBPC in acetonitrile (CH3CN) solution.

Transformation products:

not specified

Details on hydrolysis and appearance of transformation product(s):

Not provided.

% Recovery:

100

pH:

4

Temp.:

50 °C

Duration:

5 d

Remarks on result:

other: recovery determined to be 104.1 %

Remarks:

(substance hydrolytically stable)

% Recovery:

100

pH:

7

Temp.:

50 °C

Duration:

5 d

Remarks on result:

other: recovery determined to be 103.5 %

Remarks:

(substance hydrolytically stable)

% Recovery:

100

pH:

9

Temp.:

50 °C

Duration:

5 d

Remarks on result:

other: recovery determined to be 100.2 %

Remarks:

(substance hydrolytically stable)

Remarks on result:

hydrolytically stable based on preliminary test

Observed DMBPC Concentrations in Buffer Test Solutions.

Buffer	Day 0 DMBPC (µg/L)	% RSD	Day 5 DMBPC (µg/L)	% RSD	% Recovery
pH 4	345	2.0	359	1.7	104.1
pH 7	340	3.1	352	2.0	103.5
pH 9	480	2.4	481	1.4	100.2

%RSD = percent relative Standard Deviation [i.e. (standard deviation/mean) x 100]

 

Validity criteria fulfilled:

yes

Conclusions:

DMBPC as a saturated solution in aqueous buffers at pH 4.0, 7.0 and 9.0 was found to be hydrolytically stable after 5.0 days at 50 °C.

Executive summary:

The potential of the test material to undergo hydrolysis was investigated in accordance with the standardised guideline OECD 111 under GLP conditions.

The analytical method for determination of trace amounts of DMBPC in water was an HPLC gradient method which used a standard C18 reverse phase column, a water/acetonitrile gradient, and UV detection at 230 nm.

The hydrolysis in water was evaluated in a five day study at pH 4, 7 and 9 at 50 °C. The initial concentration of DMBPC was 345 µg/L. There was no loss of the test substance after 5 d. Therefore, no value could be determined for half-life.

DMBPC as a saturated solution in aqueous buffers at pH 4.0, 7.0 and 9.0 was found to be hydrolytically stable after 5.0 d at 50 °C. At pH 4, 7 and 9, the percent recovery values were 104.1, 103.5 and 100.2, respectively. Therefore, DMBPC is not amenable to abiotic degradation via hydrolysis (i.e., is stable in water).

Description of key information

DMBPC is not amenable to abiotic degradation via hydrolysis (i.e., is stable in water).

Additional information

The potential of the test material to undergo hydrolysis was investigated in accordance with the standardised guideline OECD 111 under GLP conditions. The study was awarded a reliability score of 1 in accordance with the criteria set forth by Klimisch et al. (1997).

The analytical method for determination of trace amounts of DMBPC in water was an HPLC gradient method which used a standard C18 reverse phase column, a water/acetonitrile gradient, and UV detection at 230 nm.

The hydrolysis in water was evaluated in a five day study at pH 4, 7 and 9 at 50 °C. The initial concentration of DMBPC was 345 µg/L. There was no loss of the test substance after 5 d. Therefore, no value could be determined for half-life.

DMBPC as a saturated solution in aqueous buffers at pH 4.0, 7.0 and 9.0 was found to be hydrolytically stable after 5.0 d at 50 °C. At pH 4, 7 and 9, the percent recovery values were 104.1, 103.5 and 100.2, respectively. Therefore, DMBPC is not amenable to abiotic degradation via hydrolysis (i.e., is stable in water).