Selective determination method for measurement of nitrite and nitrate in water samples using high-performance liquid chromatography with post-column photochemical reaction and chemiluminescence detection

Rapid Method for Simultaneous Determination of Nitrite and Nitrate in Water Samples Using Short-Column Ion-Pair Chromatographic Separation, Photochemical Reaction, and Chemiluminescence Detection

“…10 The system assembly consisted of LC-20AD HPLC pumps (Shimadzu, Kyoto, Japan), a Rheodyne 7125 sample injector (Rheodyne, CA) equipped with a 5-μL sample loop, a short ODS column (XBridge guard column, 5 μm, 20 mm × 4.6 mm i.d., Waters, MA), a custom-made photochemical reactor, a Comet 2000 chemiluminescence detector (Comet, Kanagawa, Japan), and a Hitachi D-2500 (Hitachi, Tokyo, Japan) data processor. The photochemical reactor consisted of a low-pressure mercury lamp (15 W, CL-15, National, Tokyo, Japan) and a reaction coil in a plastic box covered with aluminum tape.…”

“…10 Anion separation by ion-pair chromatography using an ODS column can be achieved using two approaches. One approach is to use a cationic hydrophobic reagent in the eluent as a dynamic anion exchanger.…”

“…On the basis of our previous report, 10 methanol was selected as the organic solvent. The retention time decreased with increasing methanol concentration, as shown in Fig.…”

“…On the basis of this finding, we proposed a highly sensitive method for the simultaneous determination of nitrite and nitrate in water samples. 10 The reduction of nitrate and nitrite to NO and the generation of peroxynitrite can only be completed via UV irradiation; therefore, this detection system is very simple. In addition, because sensitivity to nitrite was 10 times higher than that to nitrate, simultaneous determination could be achieved.…”

“…However, this method employed the same separation system as that used in conventional ion chromatography, which required an expensive ion-exchange column and a long time for analysis. 10 Compared with ion chromatography, ion-pair chromatography has better chromatographic efficiency and greater flexibility in terms of choice of columns, eluent, and ion-pair reagents for optimum separation. Most importantly, the use of a cationic surfactant-coated monolith silica octadecylsilane (ODS) column allows ultra-fast separation of the 8 most common anions within 15 s.…”