Sodium 1-(3,4-dihydro-6-methyl-2,4-dioxo-2H-pyran-3-ylidene)ethanolate

Water solubility

Link to relevant study record(s)

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

Guideline:

OECD Guideline 105 (Water Solubility)

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

GLP compliance:

yes (incl. QA statement)

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