Dihydrogen bis[monoperoxyphthalato(2-)-O1,OO1]magnesate(2-)

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Deviations:

not applicable

GLP compliance:

no

Remarks:

but the studies follow quality assurance standards

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

Samples were taken at six to seven spaced points troughout the study duration. Samples stored at 7 °C before analysis.

Buffers:

Buffer solution pH 4.4:
No buffer necessary, only H2O was used
Buffer solution pH 6.9:
0.1 M phosphate buffer: 680 mg KH2PO4 (Merck, Darmstadt) and 2.98 mL 1 M NaOH (Merck, Darmstadt) filled up to 50mL with H2O
Buffer solution pH 8.8:
0.2 M borate buffer: 618 mg boric acid (Merck, Darmstadt) and 3.98 mL 1 M NaOH (Merck, Darmstadt) were filled up to 50 mL with H2O

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: 5 mm NMR tubes

TEST MEDIUM
- Test concentrations: 2% MMPP
- Preparation of test medium: 2% MMPP in H2O or buffer/ D2O (90/10 %v/v)
- Replicates: Single replicate for each measuring date

Duration:

21.07 h

pH:

4.4

Temp.:

27 °C

Initial conc. measured:

2 other: %

Duration:

22.81 h

pH:

6.9

Temp.:

27 °C

Initial conc. measured:

2 other: %

Duration:

12.3 h

pH:

8.8

Temp.:

27 °C

Initial conc. measured:

2 other: %

Statistical methods:

r2 > 0.9 in all log concentration/ time relationships

Preliminary study:

none

Transformation products:

yes

No.:

#1

pH:

4.4

Temp.:

27 °C

DT50:

6.04 h

pH:

6.9

Temp.:

27 °C

Remarks on result:

not determinable

Remarks:

Dt50 can not be calculated due to possible interference of the test compound with the phosphate buffer used

pH:

8.8

Temp.:

27 °C

DT50:

3.21 h

Degradation products were Phthalic acid and H₂O₂ (not detectable via ¹³C-NMR).

Validity criteria fulfilled:

yes

Conclusions:

The studies clearly prove rapid hydrolysis of MMPP. Products of hydrolysis are Phthalic acid and H2O2. Complete hydrolysis is to be expected under environmental conditions and in human body fluids.

Executive summary:

The hydrolysis of MMPP was studied using 13C-NMR technique. The test substance was mixed with H2O/D2O to obtain a 2% solution at 27°C; pH values were adjusted to 4.4, 6.9 and 8.8. The degree of hydrolysis was measured by detection of MMPP and Phthalic acid via the 13C-NMR-spectra.

Samples were analysed at the start of the test and at minimum 5 spaced time points during the test. The concentrations were analysed via NMR spectrometer.

The substance hydrolyses at pH 4.4, 6.9 and 8.8.

Degradation products were Phthalic acid and H2O2 (not detectable via 13C-NMR).