Flow-injection is a technique to perform sample manipulations such as reagent addition, dilution, preconcentration and simple separations with a manifold on-line coupled with the detection system.
With respect to separation only non-chromatographic techniques such as solid-phase extraction, capillary microextraction (CPE), liquid-liquid extraction or precipitation can be applied. Since the separation power of such separation techniques is rather limited, only simple separation problems can be realized. With respect to elemental species, FI-ICP-MS is mainly be used to perform "binary fractionation" of species such as inorganic arsenic vs. organic arsenic, hexavalent chromium vs. trivalent chromium etc.
The main advantage of FI-ICP-MS for such purpose is automation: the whole process is integrated into a manifold and its control is programmed leading to a fast and reproducible operation. Further, the flow-injection manifold provides a closed system, permanently flushed with carrier solution, limiting contamination problems from the environment.
Of course any non-chromatographic separation method can also be used off-line, collecting the separated fractions and determining the elemental content by ICP-MS. Especially liquid phase microextraction and cloud point extraction have been proposed for speciation analysis. However such off-line procedures lack automation and involve tedious manual work, lack reproducibility, are prone to contamination and are therefore no longer state-of-the art.
Speciation analytical methods using FI-ICP-MS
Ewelina Kowa, Anna Telk, Marcin Wieczorek,
Flow techniques in the analysis of biological samples by inductively coupled plasma mass spectrometry - a review, J. Anal. At. Spectrom., 2024.
DOI: 10.1039/d3ja00412k Shizhong Chen, Shengping Zhu, Yuanyuan He, Dengbo Lu,
Speciation of chromium and its distribution in tea leaves and tea infusion using titanium dioxide nanotubes packed microcolumn coupled with inductively coupled plasma mass spectrometry, Food Chemistry, 150 (2014) 254–259.
doi: 10.1016/j.foodchem.2013.10.150 Keng-Chang Hsu, Chien-Che Sun, Yong-Chien Ling, Shiuh-Jen Jiang, Yeou-Lih Huang,
An on-line microfluidic device coupled with inductively coupled plasma mass spectrometry for chromium speciation, J. Anal. At. Spectrom., 28 (2013) 1320.
doi: 10.1039/c3ja50030f
Andrea Spolaor, Paul Vallelonga, Jacopo Gabrieli, Giulio Cozzi, Claude Boutron, Carlo Barbante,
Determination of Fe2+ and Fe3+ species by FIA-CRC-ICP-MS in Antarctic ice samples, J. Anal. At. Spectrom., 2012, 27, 310.
doi: 10.1039/c1ja10276a
A. Calvo Fornieles, A. Garcia de Torres, E. Vereda Alonso, M. T. Siles Cordero, J.M. Cano Pavon,
Speciation of antimony(III) and antimony(V)
in seawater by flow injection solid phase extraction coupled with
online hydride generation inductively coupled plasma mass spectrometry, J. Anal. At. Spectrom., 26 (2011) 1619.
doi: 10.1039/c0ja00273a
M.V. Balarama Krishna, K. Chandrasekaran, D. Karunasagar,
On-line speciation of inorganic and methyl mercury
in waters and fish tissues using polyaniline micro-column and flow
injection-chemical vapour generation-inductively coupled plasma mass
spectrometry (FI-CVG-ICPMS), Talanta 81 (2010) 462–472.
doi: 10.1016/j.talanta.2009.12.024
Yan-Feng Huang, Yan Li, Yan Jiang, Xiu-Ping Yan,
Magnetic immobilization of amine-functionalized magnetite microspheres in a knotted reactor for on-line solid-phase extraction coupled with ICP-MS for speciation analysis of trace chromium, J. Anal. At. Spectrom., 25 (2010) 1467–1474.
doi: 10.1039/c004272b
Fei Zheng, Bin Hu,
Dual silica monolithic capillary microextraction (CME) on-line coupled with ICP-MS for sequential determination of inorganic arsenic and selenium species in natural waters, J. Anal. At. Spectrom., 24 (2009) 1051–1061.
doi: 10.1039/b900057g
Jiankun Duan, Bin Hu,
Speciation of selenomethionine and selenocystine using online micro-column containing Cu(II) loaded nanometer-sized Al2O3 coupled with ICP-MS detection, Talanta 79 (2009) 734–738.
doi: 10.1016/j.talanta.2009.04.063 Wenling Hu, Fei Zheng, Bin Hu,
Simultaneous separation and speciation of inorganic As(III)/As(V) and Cr(III)/Cr(VI) in natural waters utilizing capillary microextraction on ordered mesoporous Al2O3 prior to their on-line determination by ICP-MS, Journal of Hazardous Materials, 151 (2008) 58–64.
doi:10.1016/j.jhazmat.2007.05.044 Kritsana Jitmanee, Norio Teshima, Tadao Sakai, Kate Grudpan,
DRC ICP-MS coupled with automated flow injection system with anion exchange minicolumns for determination of selenium compounds in water samples, Talanta 73 (2007) 352–357.
doi: 10.1016/j.talanta.2007.03.054 Xuli Pu, Bin Hu, Zucheng Jiang, Chaozhang Huang,
Speciation of dissolved iron(II) and iron(III) in environmental water samples by gallic acid-modified nanometer-sized alumina micro-column separation and ICP-MS determination, Analyst, 130 (2005) 1175–1181.
doi: 10.1039/b502548f Chunhai Yu, Qiantao Cai, Zhong-Xian Guo, Zhaoguang Yang, Soo Beng Khoo,
Simultaneous speciation of inorganic selenium and tellurium by inductively coupled plasma mass spectrometry following selective solid-phase extraction separation, J. Anal. At. Spectrom., 19 (2004) 410–413.
doi: 10.1039/b310318h A.R. Elwaer, C.W. McLeod,K.C. Thompson,
On-Line Separation and Determination of Bromate in Drinking Waters Using Flow Injection ICP Mass Spectrometry, Anal. Chem. 72 (2000) 5725-5730.
doi: 10.1021/ac0007433
Related EVISA Resources
Company Database: Manufacturers of FIA Instruments
Instrument Database: Atomic Fluorescence Systems 
Further chapters on techniques and methodology for speciation analysis:
Chapter 1:
Tools for elemental speciation Chapter 2: ICP-MS - A versatile detection system for speciation analysis Chapter 3: LC-ICP-MS - The most often used hyphenated system for speciation analysis Chapter 4: GC-ICP-MS- A very sensitive hyphenated system for speciation analysis Chapter 5: CE-ICP-MS for speciation analysis Chapter 6: ESI-MS: The tool for the identification of species Chapter 7: Speciation Analysis - Striving for Quality Chapter 8: Atomic Fluorescence Spectrometry as a Detection System for Speciation Analysis Chapter 9: Gas chromatography for the separation of elemental species Chapter 10: Plasma source detection techniques for gas chromatography Chapter 11: Fractionation as a first step towards speciation analysis Chapter 12: Flow-injection inductively coupled plasma mass spectrometry for speciation analysis Chapter
13: Gel electrophoresis combined with laser ablation inductively
coupled plasma mass spectrometry for speciation analysis Chapter 14: Non-chromatographic separation techniques for speciation analysis
