Hexasodium 4,4'-[1,4-phenylenebis[imino(6-chloro-1,3,5-triazine-4,2-diyl)imino]]bis[5-hydroxy-6-[(2-sulphonatophenyl)azo]naphthalene-2,7-disulphonate]

Hydrolysis

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

March 2018

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Principles of method if other than guideline:

Only a pre-liminary study is performed. In this study the degradation products were identified.

GLP compliance:

no

Remarks:

this internal study was used as verification the Laus study and followed the same protocol

Radiolabelling:

no

Analytical monitoring:

yes

Remarks:

HPLC UV

Buffers:

pH 4
CHCOOH, 2 M 16.0 mL
CH3COONa 8 mL
Demineralised water ad 200 mL
pH is adjusted using NaOH or acetic acid, if necessary

pH 7
KH2PO4 1.7417 g
Demineralised water 100 mL
NaOH, 2 M 2.98 mL
Demineralised water ad 200 mL
pH is adjusted using NaOH or phosphoric acid, if necessary

pH 9
H3BO3 0.6186 g
KCl 0.7458 g
Demineralised water 100 mL
NaOH, 2 M 2.15 mL
Demineralised water ad 200 mL
pH is adjusted using NaOH or boric acid, if necessary

Duration:

120 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

250 mg/L

Duration:

120 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

250 mg/L

Duration:

120 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

250 mg/L

Duration:

10 h

pH:

10

Temp.:

80 °C

Remarks:

pH 10-11; A 15% RR120 solution was prepared, and then one drop of that solution was diluted in 10 mL 50:50 MeOH:DI water

Number of replicates:

2/pH

Positive controls:

yes

Remarks:

an additional sample was hydrolysed at pH 10-11 to identify the degradation products

Statistical methods:

NA

Preliminary study:

Results see below

Transformation products:

yes

No.:

#1

No.:

#2

pH:

4

Temp.:

50 °C

Remarks on result:

not measured/tested

Remarks:

see table for results

pH:

7

Temp.:

50 °C

Remarks on result:

not measured/tested

Remarks:

see table for results

pH:

9

Temp.:

50 °C

Remarks on result:

not measured/tested

Remarks:

see table for results

pH:

10

Temp.:

80 °C

Remarks on result:

not measured/tested

Remarks:

see table for results

 The results of the OECD Guideline 111 study  

	Reactive Red 120 (area % HPLC)	Hydrolysis Product 1 (area % HPLC)	Hydrolysis Product 2 (area % HPLC)
pH 4 – a	67.7	28.6	3.7
pH 4 – b	65.5	30.4	4.1
pH 7 – a	94.6	4.3	1.1
pH 7 – b	95.8	3.1	1.1
pH 9 – a	88.8	9.2	2.0
pH 9 – b	88.6	9.8	1.6

Hydrolysis Study of Reactive Red 120 at 80°C at a pH range of 10-11

 

Time (Hours)	Reactive Red 120 (area % HPLC)	Hydrolysis Product 1 (area % HPLC)	Hydrolysis Product 2 (area % HPLC)
Initial	100.0
2	84.9	15.1
4	40.5	29.8	29.7
8	7.2	15.5	77.3
10	1.6	1.2	97.2

 

    

Conclusions:

The core molecule (chromophore) is concluded to be hydrolytically stable

Executive summary:

In a hydrolysis study performed acording to the protocol as described in OECD 111, the substance hydrolysed ca 35% at pH 4 and ca 10% pH 9. The hydrolysis products were identified. It was shown that the core molecule (chromophore) of the substance remains intact and the hydrolysis is related tothe chloride on the molecule.

The core molecule (chromophore) is therefore concluded to be hydrolytically stable

Reference 2

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

31 January 2018 to 05 February 2018

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)

Principles of method if other than guideline:

Only Tier 1 test

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

Solvent for stock solution: Demineralised water
Solvent for calibration: Demineralised water

Buffers:

Buffer-Solution, pH 4
Parameter Amount
CH3COOH, 2 M 16.0 mL
CH3COONa 8 mL
Demineralised water ad 200 mL
pH is adjusted using NaOH or acetic acid, if necessary

Buffer-Solution, pH 7
Parameter Amount
KH2PO4 1.7417 g
Demineralised water 100 mL
NaOH, 2 M 2.98 mL
Demineralised water Ad 200 mL
pH is adjusted using NaOH or phosphoric acid, if necessary

Buffer-Solution, pH 9
Parameter Amount
H3BO3 0.6186 g
KCl 0.7458 g
Demineralised water 100 mL
NaOH, 2 M 2.15 mL
Demineralised water Ad 200 mL
pH is adjusted using NaOH or boric acid, if necessary

Details on test conditions:

A test item stock solution with concentration 500 mg/L was prepared by dissolving 25 mg test item in 50 mL demineralised water. This solution was mixed 1:1 with the appropriate hydrolysis buffer solution, resulting a test concentration of 500 mg/L.
The test solutions were filtered over 0.2 µm PTFE filters directly into autoclaved HPLC vials, leaving only a small headspace. The vials were then purged with sterile Argon and quickly closed using PTFE coated seals. One vial of each pH was analysed directly, the remaining three vials were stored at 50 °C in an incubation chamber for five days.

Duration:

5 d

pH:

4

Temp.:

50 °C

Initial conc. measured:

>= 248.1 - <= 251 mg/L

Remarks:

analysed in duplicate

Duration:

5 d

pH:

7

Temp.:

50 °C

Initial conc. measured:

>= 251.9 - <= 255 mg/L

Remarks:

analysed in duplicate

Duration:

5 d

pH:

9

Temp.:

50 °C

Initial conc. measured:

>= 254.8 - <= 255.2 mg/L

Remarks:

analysed in duplicate

Number of replicates:

4(1 anaysed on day 0 and 3 analysed on day 5)

Positive controls:

no

Negative controls:

yes

Remarks:

blanks were included

Statistical methods:

NA

Preliminary study:

Hydrolysis observed at pH 4 (-53.3%) and 9 (-9.5%)

Transformation products:

not measured

pH:

4

Temp.:

50 °C

Remarks on result:

not measured/tested

pH:

7

Temp.:

50 °C

Remarks on result:

not measured/tested

pH:

9

Temp.:

50 °C

Remarks on result:

not measured/tested

	Mean Concentrations [mg/L]
	pH 4	pH 7	pH 9
t = 0 h	249.6	253.5	255.1
t = 120 h	116.6	253.1	231.0
Recovery after 120 h [%]	46.7	99.9	90.5
Change over 120h[%]	-53.3	-0.1	-9.5

 

Validity criteria fulfilled:

yes

Conclusions:

No significant signs of hydrolysis were observed at pH 7. A decrease in test item concen-tration of 9.5 % was observed at pH 9 and a decrease of 53.3 % was observed at pH 4.

Executive summary:

In a preliminary test at pH 4, 7 and 9 according to OECD 111, No significant signs of hydrolysis were observed at pH 7. A decrease in test item concentration of 9.5 % was observed at pH 9 and a decrease of 53.3 % was observed at pH 4.

Description of key information

In a preliminary test at pH 4, 7 and 9 according to OECD 111, No significant signs of hydrolysis were observed at pH 7. A decrease in test item concentration of 9.5 % was observed at pH 9 and a decrease of 53.3 % was observed at pH 4 (Laus 2018).

In a hydrolysis study performed acording to the protocol as described in OECD 111, the substance hydrolysed ca 35% at pH 4 and ca 10% pH 9. The hydrolysis products were identified. It was shown that the core molecule (chromophore) of the substance remains intact and the hydrolysis is related to the chloride on the molecule. The core molecule (chromophore) is therefore concluded to be hydrolytically stable (Kemira 2018)

Key value for chemical safety assessment

Half-life for hydrolysis:

1 yr

at the temperature of:

50 °C