GB/T 32954-2016Determination of fluoride content for fertilizers - Ion selective electrode method (English PDF)

1 Scope

This standard specifies the determination of fluoride in fertilizers by ion selective electrode.

This standard is applicable to the determination of acid-soluble fluorides (in terms of F) in phosphorus-containing fertilizers.

The detection limit of this method is 2.5µg, the linear range is 0 ~ 20µg/mL.

2 normative reference documents

The following documents are indispensable for the application of this document. For dated references, only the dated edition applies to this article

Pieces. For undated references, the latest edition (including all modifications) applies to this document.

GB/T 602 Preparation of standard solutions for the determination of impurities in chemical reagents

Preparation of preparations and preparations for use in the test methods for chemical reagents GB/T 603

GB/T 6682 Analytical laboratory water specifications and test methods

GB/T 8571 Compound Fertilizer Laboratory Sample Preparation

3 method summary

Fluoride ion selective electrode of lanthanum fluoride single crystal membrane on the fluoride ion selective logarithmic response, fluoride electrode and saturated calomel electrode in the measured

In the test solution, the potential difference can be changed with the change of the activity of fluoride ions in the solution. The change of the potential is in accord with the equation.

E = E0-

2.303RT

F logcF

E is linear with 1ogcF-. 2.303RT/F is the slope of the line (59.16 at 25 ° C).

4 reagents and solutions

The reagents used in this standard, unless otherwise specified, are of analytical grade. Laboratory water should meet the GB/T 6682 in the three water specifications.

The solution used in the analysis was prepared according to GB/T 602, GB/T 603 when no other requirements were indicated.