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Physical & Chemical properties

Water solubility

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Reference
Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Sept 2016
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Qualifier:
according to
Guideline:
OECD Guideline 105 (Water Solubility)
Qualifier:
according to
Guideline:
EU Method A.6 (Water Solubility)
GLP compliance:
yes (incl. certificate)
Remarks:
Staatliches Gewerbeaufsichtsamt Hildesheim, Germany
Type of method:
flask method
Key result
Water solubility:
231 g/L
Conc. based on:
test mat.
Loading of aqueous phase:
500 g/L
Incubation duration:
>= 24 - <= 72 h
Temp.:
20 °C
pH:
8.6

Method validation

The method showed acceptable results for linearity, accuracy, precision and specificity according to SANCO 3028/99 rev.4 (2000) and fulfilled all study plan requirements. Acceptance criteria and results of the method validation parameter are shown in table below:

Table: Parameter, Acceptance Criteria and Results of the Method Validation

Parameter

Acceptance criteria

Result

Linearity

5 Standard concentrations,

r² ≥ 0.992

1 to 50 mg test item/L (n=6),

r² ≥ 0.992

Lowest calibration standard

S/N ≥ 9

1 mg test item/L, S/N = 11

Limit of Detection (LOD)

S/N ≥ 3

0.5 mg test item/L, S/N = 5

Limit of Quantification (LOQ)

At least 20% above lowest calibration standard after sample preparation

10 g test item/L (1 x LOQ)

50 g test item/L (5 x LOQ)

Dilution factor of 5000

Accuracy (Fortified samples)

Mean recovery rate of 70-110% (ideally 80-100%) per fortification level (2 levels)

1 x LOQ: 97% (n=5)

5 x LOQ: 107% (n=5)

Precision

Relative standard deviation ≤ 20% per fortification level

1 x LOQ: 0.93%

5 x LOQ: 0.45%

Specificity

Comparison of spectra of sample peaks against spectra obtained from standard peaks

Spectra compared and test item verified

Blank values < 30% of LOQ

Blank values < 30% of LOQ (no significant signal)

√ = criterion fulfilled

Table: Recovery Rates of Fortified Samples in Double Distilled Water

Fortified concentration: 10.069 g/L (nominal 10 g/L, 1 x LOQ) and 50.345 g/L (nominal 50 g/L, 5 x LOQ)

Replicate No

1 x LOQ

5 x LOQ

Calc. conc. [g/L]

RR [%]

Calc. conc. [g/L]

RR [%]

1

9.71

96

53.6

106

2

9.82

98

536.

106

3

9.71

96

53.7

107

4

9.81

97

54.1

107

5

9.93

99

53.5

106

Mean

9.80

97

53.7

107

SD

0.09

0.2

CV [%]

0.93

0.45

 

Calc. conc. = Calculated concentration, exact weight and dilution factor of 5000 taken into account

RR = Recovery rate, related to the fortified concentration

SD = Standard deviation

CV = Coefficient of variation

Check of temperature

Table: Temperature at Pre-Incubation (30 °C) and Thermostatisation Phase (20 °C) (measured hourly)

Intended temperature [°C]

Measured temperature [°C]

Min.

Max.

Mean value ± SD

30.0 ± 0.5

29.83

30.06

29.94 ± 0.06

20.0 ± 0.5

19.89

20.15

19.95 ± 0.05

 The additional manual values confirm the values of the data logger.

 

Check of the pH-Value

The pH-values were determined with the remaining test item mixtures in the original test vessels, which were kept constant at 20 ± 0.5 °C.

Table: pH-Value of the Test Mixture for Double Distilled Water

Test temperature [°C]

Pre-incubation time [h]

Replicate

Measured pH

Mean value

20

24

1

8.650

8.6

2

8.664

48

1

8.652

2

8.623

72

1

8.656

2

8.651

Control

7.018

-

 

Check of Tyndall effect

Table: Check of the Tyndall-Effect

Pre-incubation time

Replicate

Tyndall-Effect

24 h

1

negative

2

negative

48 h

1

negative

2

negative

72 h

1

negative

2

negative

Control

negative

  

Water Solubility Results

No significant signals were obtained for the control sample.

Table: Water Solubility Results for 20 °C for Dehydroacetic acid sodium salt

Pre-incubation time

Replicate No.

Dehydroacetic acid sodium salt [g/L]

Concentration 1)

Mean

24 h

1

232

231

2

231

48 h

1

228

230

2

232

72 h

1

232

231

2

230

Mean (24 – 72 h)

 

231

Deviation [%] (24-72 h) 2)

0.5

1) Mean value of two injections, dilution factor of 10000 and exact weight of the standard taken into account

2) Calculated according to formula given above

Description of key information

The substance dehydroacetic acid sodium salt has a water solubility of 231 g/L at 20 °C, pH = 8.6 (OECD 105, shake flask method).

Key value for chemical safety assessment

Water solubility:
231 g/L
at the temperature of:
20 °C

Additional information