Total organic carbon measurement device and total organic carbon measurement method

Abstract

A total organic carbon (TOC) measuring apparatus and method are provided. This relatively inexpensive TOC measuring apparatus, which uses an instant-on ultraviolet lamp and has only one conductivity measuring unit, can accurately measure the TOC of ultrapure water. The TOC measuring apparatus includes: an oxidation unit having a sample flow channel through which sample water passes, and an instant-on ultraviolet lamp disposed along the sample flow channel and irradiating the sample flow channel with ultraviolet light; a conductivity measuring unit for measuring conductivity; a pump for conveying sample water; a control unit for alternately performing a first measurement action and a second measurement action; and a calculation unit for calculating TOC based on the conductivity. The first measurement action includes: an oxidation treatment step, in which sample water is retained in a sample channel for a predetermined time and oxidation treatment is applied while the ultraviolet lamp is lit; and a first measurement step, in which the first conductivity of the oxidized sample is measured; the second measurement action includes: a non-oxidation treatment step, in which sample water is retained in a sample channel for the predetermined time while the ultraviolet lamp is turned off; and a second measurement step, in which the second conductivity of the sample after retention in the non-oxidation treatment step is measured; the calculation unit calculates TOC based on the difference between the first conductivity and the second conductivity.

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