Sampling device of Karl Fischer titrator and sampling method thereof

Abstract

The invention relates to a sampling device of a Karl Fischer titrator and a sampling method thereof. The sampling device provided by the invention comprises a tray, an elastic bonding material and a fine needle, wherein the outer diameter of the tray is not larger than that of the lower end of a flask cover, the tray is bonded to the lower end of the cover of a reaction flask by the elastic bonding material and is positioned above the liquid level in the reaction flask; the fine needle penetrates through a plastic spacer for sealing an opening in the upper end of the flask cover, props against the tray bonded at the lower end of the flask cover and can separate the tray from the flask cover so as to enable the tray to fall into liquid in the reaction flask. The sampling method of the sampling device comprises the following steps that: when closing is implemented firstly, the tray is fixed by the elastic bonding material and then sealed above the liquid level inside the reaction; when the guiding is implemented subsequently, the fine needle penetrates through the plastic spacer for sealing the opening in the upper end of the reaction flask, and then a sample enters a reaction tank together with the tray. Therefore, the problem that a sealing environment is established for the sample in advance, but then the sealing is difficult to overcome can be solved, and the purposes that a measurement method is easy to operate, and that the measurement is accurate can be achieved.

Description

technical field [0001] The invention relates to equipment for measuring moisture in samples by Karl Fischer method, in particular to a sampling device and a sampling method for a Karl Fischer titrator. Background technique [0002] Moisture determination of solid samples is an important detection content in the fields of pharmaceutical analysis, food analysis, organic chemical analysis, and inorganic chemical analysis. Water is a common chemical analysis target, and the most commonly used determination method is the national standard method "GB / T 606-2003 General method for the determination of moisture in chemical reagents Karl Fischer method". The experimental principle is to use Karl Fischer reagent (a solution composed of iodine, sulfur dioxide, pyridine and methanol or ethylene glycol methyl ether) to quantitatively react with the water in the sample, so as to measure the concentration of water according to the reaction product or the current generated by the reaction. ...

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Problems solved by technology

This method has the following disadvantages: due to the need to add a set of devices, thereby increasing the economic cost; moreover, because the inert gas may contain a small amount of moisture, there will be a moisture background value, if the moisture content in the measured sample is close to or less than the moisture background value When , the accuracy of the measurement results will be poor; in addition, because the moisture inside the solid sample may not be heated and volatilized, the measurement results will be lower than the actual value

However, for the sake of reality, "airtight first, then import", often leads to complicated device composition

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