AIR FORMALDEHYDE ANALYZER Russian patent published in 2023 - IPC G01N21/75 

FIELD: analytical chemistry.

SUBSTANCE: used to determine low concentrations of formaldehyde in the air. The formaldehyde analyzer in the air consists of a housing, an air purification filter, while the air sampling pump is located in the housing, an air flow regulator to maintain a stable air flow of 1 l/min, an air purification filter that provides cleaning from dust and small particles, a valve switching the air sample to the mixer coil through the segmenting switch of the peristaltic pump or to the filter for cleaning the reference air when calibrating the device, while the mixer coil provides mixing and condensation of formaldehyde from the air sample with a desorbing component - a weak solution of sulfuric acid 1-4%, a semiconductor cooler for cooling and keeping warm 10°C, mixing coil for complete dissolution in the desorbing component through the peristaltic pump, while supplying the desorbing component from the external storage tank through the peristaltic pump to the mixing coil with a stable flow rate of 0.45 ml/min, and switching the peristaltic pump provides a segmented air sample supply and the desorbing component into the mixing coil, as well as supplying the standard mixture of formaldehyde and clean air for calibrating the device, a separator-distributor that removes air bubbles from the liquid with dissolved formaldehyde, a storage tank for the Hantzch reagent, where the Hantzch reagent enters the coil through a peristaltic pump - a reactor that mixes the liquid with dissolved formaldehyde and Hantzch's reagent, a heater that heats the resulting mixture to a temperature of 68°C in the reactor coil, an air degasser that extracts air from the fluorescent complex obtained in the reactor coil, a flow chamber in which the fluorescent complex is irradiated with an ultraviolet LED and the fluorescence amplitude is measured by a photodetector, a photomultiplier amplifier that amplifies the photodetector signal, a controller, which processes the data of the photomultiplier amplifier, converts the concentration of formaldehyde in the air sample into numerical values, contains previously obtained data and controls all the automation of the device, a storage module for a substance with a reference formaldehyde content, a filter for cleaning the air sample from formaldehyde, which is used to calibrate the device.

EFFECT: increase in accuracy and the possibility of determining low concentrations of formaldehyde in a gaseous medium in automatic mode with stable parameters, such as accuracy and repeatability, as well as self-calibration of the proposed device in automatic mode.

1 dwg