Ascophyllum nodosum, ext.

Surface tension

Link to relevant study record(s)

Reference

Endpoint:

surface tension

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14-Oct-2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: This study has been performed according to OECD and EU guidelines and according to GLP principles.

Qualifier:

according to guideline

Guideline:

OECD Guideline 115 (Surface Tension of Aqueous Solutions)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.5 (Surface Tension)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

ring method

Surface tension:

51.1 mN/m

Temp.:

20 °C

Conc.:

1 g/L

Remarks on result:

other: mean of three determinations

Results

The determinations were performed at 20.0 ±and at this temperature, the tabulate value for water is 72.75 mN/m.

 

After zero point adjustment, the surface tension of the distilled water (sg) was determined to be 72.42 mN/m; therefore the calibration factor was calculated to be f (water) = 1.0045.

 

The test item was tested at aqueous dilutions of 1 g/L, in accordance with OJEC indications.

The aqueous solution was maintained at 20.0 ±in a thermostatic oven and then tested.

 

Six measurements were performed at; data are reported in Table 1 and results in Tables 2 and 3.

 

TABLE 1 Algea Fert Solid K +: surface tension values at.

                  Measurement values

 

Measurements	Test item dilution 1 g/L (mN/m)	Measurements	Test item dilution 1 g/L (mN/m)
1^st  measure	52.0	4^th  measure	52.3
2^nd  measure	52.2	5^th  measure	52.1
3^rd  measure	52.0	6^th  measure	52.0
Mean (a)			52.1
S.D.			0.12
RSD%			0.22%

 

 

TABLE 3 Algea Fert Solid K +: surface tension at.

                  Correction with water calibration

 

Measurements	Test item dilution 1 g/L (mN/m)
Mean (a) (mN/m)	52.1
Water calibration factor	1.0045
Corrected values (b) (mN/m)	52.3

  

 

TABLE 4 Algea Fert Solid K +: surface tension at.

                  Correction Table and interpolation method

 

Sample solution (mg/L)	Corrected values (b) (mN/m)	Tab. X1 (mN/m)	Tab. X2 (mN/m)	Tab. Y1 (mN/m)	Tab. Y2 (mN/m)	Slope (m)	Interc. (q)	St (mN/m)
Test item Dilution 1 g/L (mN/m)	52.3	50.7	52.8	52.0	54.0	0.9524	3.7143	51.1

Conclusions:

From the experimental data obtained according to the guideline A.5 in Official Journal L 383 Part A, it can be concluded that the surface tension at 20°C of the 1 g/L Test item aqueous solutions was 51.1 mN/m.

According to the interpretation of the results suggested in the A.5 official method, the Algea Fert Solid K +formulation sample should be regarded as a surface-active material.

Key value for chemical safety assessment

Surface tension:

51.1

in mN/m at 20°C and concentration in mg/L:

1 000