Analytical & Bioanalytical
Ogra, J Anal Bioanal Techniques 2012, 3:6
http://dx.doi.org/10.4172/2155-9872.1000e109
Techniques
Editorial
Open Access
Complementary Use of ESI-MS and ICP-MS Hyphenated with HPLC for
Identification of Metalloid Containing Metabolome
Yasumitsu Ogra*
Showa Pharmaceutical University, Tokyo, Japan
Metalloids, i.e., elements which have in-between or mixture
properties of metals and non-metals such as arsenic (As), antimony (Sb),
selenium (Se) and tellurium (Te), are utilized in the metabolic pathways
of animals and plants to form metalloid-containing compounds having
carbon-metalloid covalent bond(s) (organometallic metabolites).
Therefore, it is necessary to identify organometallic metabolites to
determine the metabolic pathway of metalloids and understand the
beneficial or toxicological effects of these compounds. However,
these metalloids exist at extremely low concentrations in animals. The
difficulty of detecting the metalloids in each organometallic metabolite
after separation on the basis of chemical properties (chemical
speciation) has been overcome with the emergence of inductively
coupled plasma-mass spectrometry (ICP-MS) as the most sensitive
and robust element detector available to date. Easily hyphenated with
HPLC, HPLC-ICP-MS is the technique of choice for the speciation
of metalloids in biological samples. However, there remains a critical
disadvantage in the identification of organometallic metabolites by
HPLC-ICP-MS. Although ICP-MS is sensitive to target elements
and is robust to matrices, it provides little molecular information of
organometallic metabolites. Thus, the identification by HPLC-ICPMS is limited to the situation where certified or authentic metalloid
species are available. As an alternative to HPLC-ICP-MS, electro spray
ionization (ESI) and atmospheric pressure chemical ionization (APCI)tandem mass spectrometry (MS-MS) is used to identify unknown
organometallic metabolites [1,2]. ESI is a softer technique than ICP,
and can provide molecular information. In addition, MS-MS enables
structure elucidation. However, ESI-MS-MS has a number of weak
points compared with ICP-MS. First, the detection limits of ESI-MS-MS
for organometallic metabolites are inferior to that of ICP-MS. Second,
ESI is severely affected by the sample matrix. To counter this problem,
ESI-MS-MS is coupled with HPLC. Therefore, the complementary use
of HPLC-ICP-MS and HPLC-ESI (APCI)-MS-MS is a powerful tool for
the speciation and identification of organometallic metabolites. Indeed,
unique metalloid-containing metabolites have been reported by the
complementary use of inorganic and organic mass spectrometers [3,4].
The evolution of instruments for speciation, particularly for the
identification of target organometallic metabolites in trace amounts
in complex matrices, has contributed immensely to the exploration of
metalloid-containing metabolome. In addition, ICP-tandem MS, i.e.,
ICP-MS-MS has been recently developed. ICP-MS-MS improves the
detections of phosphorus (P) and sulfur (S) compromised in ICP-MS
[5]. Hence, the complementary use of ICP-MS-MS and ESI-MS-MS
may be applicable to speciation/identification of non-metallic element
such as P and S-containing metabolites in near future.
References
1. Ogra Y (2008) Integrated strategies for identification of selenometabolites in
animal and plant samples. Anal Bioanal Chem 390: 1685-1689.
2. Mounicou S, Szpunar J, Lobinski R (2009) Metallomics: the concept and
technology. Chem Soc Rev 38: 1119-1138.
3. Gammelgaard B, Gabel-Jensen C, Sturup S, Hansen HR (2008) Complementary
use of molecular and element-specific mass spectrometry for identification of
selenium compounds related to human selenium metabolism. Anal Bioanal
Chem 390: 1691-1706.
4. Ogra Y, Anan Y (2009) Selenometabolomics: Identification of selenometabolites
and specification of their biological significance by complementary use of
elemental and molecular mass spectrometry. J Anal At Spectrom 24: 14771488.
5. Diez Fernandez S, Sugishama N, Ruiz Encinar J, Sanz-Medel A (2012) Triple
Quad ICPMS (ICPQQQ) as a New Tool for Absolute Quantitative Proteomics
and Phosphoproteomics. Anal Chem 84: 5851-5857.
*Corresponding author: Yasumitsu Ogra, Professor, Laboratory of Chemical
Toxicology and Environmental Health, Showa Pharmaceutical University, Machida, Tokyo,
Japan, Tel : +81 42 721 1563; Fax: +81 42 721 1563; E-mail: [email protected]
Received October 22, 2012; Accepted October 23, 2012; Published October
31, 2012
Citation: Ogra Y (2012) Complementary Use of ESI-MS and ICP-MS Hyphenated
with HPLC for Identification of Metalloid Containing Metabolome. J Anal Bioanal
Techniques 3:e109. doi:10.4172/2155-9872.1000e109
Copyright: © 2012 Ogra Y. This is an open-access article distributed under the
terms of the Creative Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium, provided the original author and
source are credited.
J Anal Bioanal Techniques
ISSN:2155-9872 JABT, an open access journal
Volume 3 • Issue 6 • 1000e109