Analytical Sciences

Multiple-channel Concentric Grid Nebulizer for Online Standard Addition in Inductively Coupled Plasma Optical Emission Spectrometry

Koyo IDO,*1,*2 Rina MATSUSHITA,*1,*3 Shin-ichiro FUJII,*4 Shin-ichi MIYASHITA,*1 Tomonari UMEMURA,*3 Akiko HOKURA,*2 and Kazumi INAGAKI*1

*1 Environmental Standards Group, National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology, Tsukuba Central 3-10, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563, Japan
*2 Graduate School of Advanced Science and Technology, Tokyo Denki University, 5 Senju Asahi-cho, Adachi, Tokyo 120-8551, Japan
*3 School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
*4 Bio-Medical Standards Group, National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology, Tsukuba Central 3, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563, Japan

A multiple channel-type concentric grid nebulizer (m-CGrid) was developed for realizing efficient online standard addition in inductively coupled plasma optical emission spectrometry (ICP-OES) without premixing of liquids before nebulization. The m-CGrid can nebulize two independent liquids without premixing due to a unique structure, having two independent liquid-flow capillaries inside a single nozzle and a grid screen (over 350 mesh per inch) placed on the hole of the nozzle. The grid acts as both a flow damper and sieve; two liquids are well-mixed with a gas flow in a small space just before the grid screen, and the mixture breaks up into small droplets by passing through the grid. The m-CGrid nebulizer provides almost the same or better spray performance compared with a conventional nebulizer, such as Meinhard nebulizer; the primary aerosols were much finer (D₅₀: 2.9 and 3.1 μm for two channels) than those generated with Meinhard nebulizer type C (D₅₀: 19.5 μm). The signal intensities in ICP-OES obtained with two liquid channels were almost the same and were 2- to 3-fold higher than that obtained with the Meinhard nebulizer for 23 elements. The performance of m-CGrid in an online standard addition was demonstrated in the analysis of NIST SRM1577b bovine liver and NIES No. 3 Chrorella. The analytical results were in good agreement with their certified values.

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