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Any analyte that can be oxidized or reduced is a candidate for amperometric detection. The simplest form of amperometric detection is single-potential, or direct current (DC), amperometry. A voltage (potential) is applied between two electrodes positioned in the column effluent. The measured current changes as an electroactive analyte is ...
The charged aerosol detector (CAD) is a detector used in conjunction with high-performance liquid chromatography (HPLC) and ultra high-performance liquid chromatography (UHPLC) to measure the amount of chemicals in a sample by creating charged aerosol particles which are detected using an electrometer.
The envelope detector has several drawbacks: The input to the detector must be band-pass filtered around the desired signal, or else the detector will simultaneously demodulate several signals. The filtering can be done with a tunable filter or, more practically, a superheterodyne receiver; It is more susceptible to noise than a product detector
Double-pulsed chronoamperometry waveform showing integrated region for charge determination.. In electrochemistry, chronoamperometry is an analytical technique in which the electric potential of the working electrode is stepped and the resulting current from faradaic processes occurring at the electrode (caused by the potential step) is monitored as a function of time.
Differential pulse voltammetry: An electrochemical technique similar to normal pulse voltammetry but the applied base potential is increased or decreased steadily, and the pulse height: base height ratio is kept constant. In DPV, measurements of current are taken twice during each drop, first immediately before the pulse and second before the ...
In LET eddy currents are generated by providing the relative motion between the conductor under test and a permanent magnet(see figure). If the magnet is passing by a defect, the Lorentz force acting on it shows a distortion whose detection is the key for the LET working principle.
Pulse-Height Analyzer Principle: Three pulses, 1, 2, and 3 are detected at different times t. Two discriminators emit a counting signal if their set voltage threshold is exceeded by a pulse. Pulse 2 triggers the Lower Level E L but not the Upper Level E U. Pulse 2 is thus counted into the spectral region denoted as P.
A special form of the Pirani gauge is the pulsed Pirani vacuum gauge where the sensor wire is not operated at a constant temperature, but is cyclically heated up to a certain temperature threshold by an increasing voltage ramp. When the threshold is reached, the heating voltage is switched off and the sensor cools down again.