On-line monitoring method of content of formaldehyde in environmental air and device

Abstract

The invention discloses an on-line monitoring method of content of formaldehyde in environmental air and a device. The on-line monitoring method comprises measurement processes including a sampling process, a reaction process and a detection process of the formaldehyde in the environmental air. The method is characterized by comprising the following steps: converting formaldehyde in the environmental air into a formaldehyde solution and taking the formaldehyde solution as a liquid-phase sample to be detected; enabling the liquid-phase sample to be detected and acetylacetone to carry out derivatization reaction under the high-temperature condition to generate a yellow compound DDL, wherein absorption in a wavelength of 415 nm is the highest; enabling a solution to repeatedly reflect and absorb light in a total-reflection flow cell by using a total-reflection long-optical-path on-line flow cell; and calculating the content of formaldehyde to obtain the content of formaldehyde in the environmental air. The on-line monitoring device comprises a machine shell, a sampling module, a reaction module, a detection module, a solution conveying module, a control and data collection circuit anda display screen. Through the method and the device, the sensitivity and the detection limit of detection of formaldehyde are improved by the long-optical-path on-line flow cell; the method and the device are applied to on-line continuous monitoring of formaldehyde in the low-concentration environmental air.

Description

technical field

[0001] The invention belongs to the technical field of environmental monitoring, and relates to an online monitoring technology of ambient air quality, in particular to an online monitoring method and device for formaldehyde content in ambient air. Background technique

[0002] Formaldehyde (HCHO) is a highly active compound. It is not only a tracer substance in the oxidation reaction of atmospheric volatile organic compounds, but also plays an important role in the photochemical reaction of free radicals and ozone. In addition to the outdoor atmosphere, formaldehyde is often detected indoors at a concentration several times that of the outdoors. The human body is exposed to high concentrations of formaldehyde for a long time, which can irritate the eyes and respiratory tract, and then cause headaches, nausea and other symptoms. In severe cases, it can induce nasopharyngeal cancer, Cancers such as leukemia. For this reason, the U.S. Environmental Protection ...

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