User Benefits
Application
News
Instrument: TOC-LCPH
Oxidation Method: Combustion Method (680 °C)
Catalyst: TOC standard catalyst
Measurement Items: TOC (NPOC method)
Injection Volume: 50 µL
Calibration Curves: 2-point calibration curve using potassium
hydrogen phthalate aqueous solutions at 0
and 20 mgC/L
Sample Preparation and Analysis Conditions
Sodium dichloroisocyanurate was dissolved in pure water to
prepare aqueous solutions with carbon concentrations of
10 mgC/L and 5 mgC/L.
The TOC measurement employed the non-purgeable organic
carbon (NPOC) method. In the NPOC method, the sample is
acidified with hydrochloric acid, then sparged to remove
inorganic carbon (IC), after which total carbon (TC) is measured
as TOC.
Table 1 Analysis Conditions (Combustion Oxidation)
The prepared sodium dichloroisocyanurate aqueous solution
was measured using the combustion oxidation TOC-L
CPH
. The
measurement conditions are detailed in Table 1, and the
measurement results are presented in Figs. 2 and 3 and in Table
2. The recoveries for both samples were over 98 %.
Introduction
In facilities where people have direct contact with water, such as
swimming pools, hot springs, and bathhouses, strict water quality
management is essential to protect public health and safety. Total
organic carbon (TOC) measurement is widely used to detect water
quality degradation caused by microbial growth and
contamination with foreign substances.
Solid powder chloroisocyanuric acids (including
dichloroisocyanuric acid and trichloroisocyanuric acid), which
exhibit minimal chlorine deactivation, are commonly used as
disinfectants for swimming pool water instead of sodium
hypochlorite solutions. However, because chlorinated isocyanuric
acid is a recalcitrant substance, it is challenging to detect using
wet oxidation TOC analyzers due to its resistance to oxidation and
decomposition. In contrast, a combustion oxidation TOC analyzer
can measure chloroisocyanuric acids with high sensitivity and
recovery rates due to its strong oxidizing power.
In this application, we compared the TOC measurement results
for sodium dichloroisocyanurate using a combustion oxidation
TOC-L
CPH
analyzer and a wet oxidation TOC-V
WP
analyzer.
Samples such as chloroisocyanuric acid, which are difficult to detect using a wet oxidation TOC analyzer, can be measured with
high sensitivity using the combustion oxidation TOC-L, which has a strong oxidizing power.
One sample can be measured quickly, typically within 10-20 minutes.
Measurement of TOC in Chloroisocyanuric Acid
Used as Disinfectant
Tomomi Higashida
Total Organic Carbon Analyzer
Analysis of Sodium Dichloroisocyanurate
Solution by Combustion Oxidation TOC-L
CPH
The equipment was calibrated using a 2-point calibration curve
using 0 and 20 mgC/L potassium hydrogen phthalate aqueous
solutions. The calibration curve is shown in Fig. 1.
Fig. 1 Calibration Curve Data (Combustion Oxidation)
Fig. 2 Measurement Result (10 mgC/L, Combustion Oxidation)
Sample
TOC Value
(mgC/L)
Recovery
(%)
10 mgC/L Sodium
dichloroisocyanurate aq.
9.893 98.9
5 mgC/L Sodium dichloroisocyanurate
aq.
4.914 98.3
Table 2 Measurement Results (Combustion Oxidation)
Fig. 3 Measurement Result (5 mgC/L, Combustion Oxidation)
