Hach TitraLab, Руководство пользователя

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Operation
4.9 System
This function can be used to adapt the titrator to specific requirements.
4.9.1 Units Acidity
The unit and factor for calculation can be adjusted individually. For example, in wine
analysis, the result can be given in g/L for sulfuric acid, tartaric acid or overall acid.
The factor is obtained in the following way:
Result = [C
NaOH
* MW * 0.5] / V
sample
C
NaOH
: sodium hydroxide concentration (mol/L) used as a titrant reagent (0.5 mol/L)
MW: molecular weight of the acid used to express the result
(150.1 g/mol tartaric acid, 98.1 g/mol sulphuric acid)
V
sample
: volume (mL) of analyzed wine, (10 ml).
In other models the factor would be calculated in a similar way.
(1) Calculated factor according to the selected units. This factor can be modified if the analysis
conditions have changed, for example the sodium hydroxide concentration or different sample
amount.
(2) Programmable factor depending on the desired units.
For example: for g/L acetic acid , NaOH 0.5 M and 2 mL of sample, the factor F=15.
(3) When the sample is in weight, version LLV2304.97.1002 for acidity in canned tomato, the
instrument performs the following calculation:
Result = [V
NaOH
(mL) * F] / sample weight (g)
4.9.2 End Point Value
Setting for titration end point. The end point can be pH 7.00 and corresponds with the
provisions of the OIV (International Organization of Vine and Wine). Alternatively, the end
point can be pH 8.20 and correspond with the provisions of the AOAC (Association of
Official Agriculture Chemistry).
Version Titrant Sample Result units Factor
(1)
LLV2301.97.1002 Wine NaOH 0.5 M 10 mL
g/L tartaric acid 3.7525
g/L sulfuric acid 2.4525
g/L 1
(2)
LLV2302.97.1002 Milk NaOH 0.1 M 10 mL
°SH 4
°D 9.09
g lactic acid/100 mL sample 0.09
LLV2304.97.1002 Tomato products NaOH 0.1 M 1 g % citric acid 0.64
(3)
LLV2306.97.1002 Brine NaOH 0.5 M 10 mL % lactic acid 0.45