CS224554B1 - Method and connexion for differential pulsating polarimetry - Google Patents

Description

The present invention relates to a method of differential pulse polarography with mercury droplet electrode polarization by a series of pulses during the life of a droplet and connection for its realization.

In prior art differential pulse polarography methods, the droplet electrode is polarized by increasing voltage with a series of pulses modulated one at a time at the end of the droplet's life.

Samples of current passing through the electrode are captured in analog memories and further evaluated. Easily using faster polarization voltage increases (mainly due to acceleration of measurement), relatively high (about 100 ms) time constants of analog memories, which ensure polarograph resistance against The use of an increase of approx. 5mV / s results in the deformation of the polarograms (shift of the half-wave potential, widening of the peaks) and thus impairing the selectivity of the assay, reducing the sensitivity, etc.

The above-mentioned drawbacks are eliminated by the differential pulse polarography method of the present invention, which is based on increasing the voltage of the droplet electrode with a modulated array of rectangular voltage pulses during the droplet life. After the last pulse, at the end of the droplet's lifetime, the voltage captured in the memories is transferred to the analog output memory, from which the recording is being taken.

The invention also relates to a circuitry comprising a line frequency pulse former, a splitter, a polarizing pulse generator and a command pulse generator, and a second splitter to which a droplet separator and an output analogue memory control are connected. The other two analog memories are connected to the polarization pulse generator and command pulses via their control inputs.

The benefit of the proposed method of differential pulse polarography and the device for its implementation is to eliminate distortion of the polarogram due to the necessary time delay in analogue memory circuits. E.g. at a time constant of analogue memories of 100 ms and a current sample duration of 20 ms, 25 samples are practically needed to fully charge them. That is, at a drop time of 2 s and a polarization voltage increase of 5 mV / s, charging is terminated after 250 mV.Depolarisers If there is a row of eg 10 pulses applied to one drop, they are three drops, ie 30 mV analogue memory already fully charged (more than 99%) ·

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It is no problem that current samples from the initial pulses contain a significant proportion of capacitive current, because it only charges the analog memories and the final - correct value is corrected until the last pulse, similar to the classical form of differential pulse polarography.

The accompanying drawings show examples of the method and connection according to the invention.

Fig. 1 shows an example of a sequence of polarizing pulses and sampling intervals, with time t plotted on the horizontal axis and voltage E plotted on the vertical axis.

At the intervals indicated by the bars Q and 10 (on each pulse), current samples are taken, at the time indicated by point 11 a drop is tapped ·

2 shows an example of wiring.

An AC voltage pulse generator 1 is connected to an AC voltage source (50 Hz). This is followed by a divider 2 which supplies the polarization pulse generator for the droplet electrode and the command pulses.

The divider 2 is also powered by a second divider controlling the droplet separator and output analog steam 6 to capture the difference in voltage values at the end of the droplet life. Analog memories 7 and 8, to capture current samples before and at the end of pulses, are controlled by generator 3.

Claims (2)

1. The method of differential pulse polarography, characterized in that the drop electrode is of increasing voltage with an unmodulated series of rectangular voltage pulses, and / or current samples are taken before and at the end of the pulse. pulse and store in two analog memories, and the difference in voltage values captured in the memories after the last pulse, at the end of the life of the drop, is transferred to the output analog memory, from which » 2. A circuit for carrying out the method according to claim 1, comprising a line frequency pulse former (1), a divider (2), a polarization pulse generator and a command pulse generator (3), and a second divider (4) to which the droplet separator (5) is connected. : and output analog memory control (β), ρίί & ωΖThe other two analog memories (7,8) are connected to the polarization pulse generator and command pulse generator (3) with their control inputs »