Inductively coupled plasma MS

The most common detectors in HPLC are ultraviolet, fluorescence, electrochemical detector and diffractometer. However, despite all improvements of these techniques it seems necessary to have a more selectivity and sensitivity detector for the purposes of the medical analysis. It should be therefore improvements to couple analytical techniques like infrared IR, MS, nuclear magnetic resonance (NMR), inductively coupled plasma-MS (ICP-MS) or biospecific detectors to the LC-system and many efforts have been made in this field. 

Determination of Trace Elements in Water and Wastes by Inductively Coupled Plasma-MS... 

Fig. 25 Schematic of an inductively coupled plasma-MS interface during ion sampling. (Reproduced with permission from Elsevier.)...

HPLC units have been interfaced with a wide range of detection techniques (e.g. spectrophotometry, fluorimetry, refractive index measurement, voltammetry and conductance) but most of them only provide elution rate information. As with other forms of chromatography, for component identification, the retention parameters have to be compared with the behaviour of known chemical species. For organo-metallic species element-specific detectors (such as spectrometers which measure atomic absorption, atomic emission and atomic fluorescence) have proved quite useful. The state-of-the-art HPLC detection system is an inductively coupled plasma/MS unit. HPLC applications (in speciation studies) include determination of metal alkyls and aryls in oils, separation of soluble species of higher molecular weight, and separation of As111, Asv, mono-, di- and trimethyl arsonic acids. There are also procedures for separating mixtures of oxyanions of N, S or P. 

T. Lindemann, H. Hintelmann, IdentiPcation of selenium-containing glutathione S-con-jugates in a yeast extract by two-dimensional liquid chromatography with inductively coupled plasma MS and nanoelectrospray MS/MS detection, Anal. Chem., 74 (2002), 4602D4610. 

One of the most exploited procedures is the complexation of metal ions. When a ligand bears a chromophore, a favorable side effect of this procedure is that sensitivity with conventional detection UV-Vis can be improved [2]. Speciation of Cr(III) and Cr(VI) in waters relied on the pre-complexation of Cr(III) with EDTA and IPC-ICP (inductively coupled plasma)-MS separation of the negatively charged chromium species in less than 2 minutes using a tetrabutylammonium IPR [3]. 

Ebden and coworkers used coupled chromatography-atomic spectroscopy for arsenic speciation. Beauchemin and collaborators identified and determined arsenic species in dogfish muscle. The arsenic species were identified using liquid chromatogra-phy-inductively coupled plasma-MS, TLC and electron impact-MS. Results indicate that arsenobetaine constitutes about 84% of the arsenic present in the sample analysed. 

The use of high-resolution inductively-coupled plasma MS was used for the sulfur-specific detection of cimetidine impurities. The stmcture of most of the impurities was subsequently confirmed by LC-ESI-MS [67]. 

E.H. Evans, J.-C. Wolff, C. Eckers, Sulfur-specific detection of impurities in cimetidine drug substance using LC coupled to high resolution inductively coupled plasma MS andESI-MS, Anal. Chem., 73 (2001) 4722. 

Wrobel, K., Sadi, B. B. M., Wrobel, K., Castillo, J. R., and Caruso, J. A., Effect of metal ions on the molecular weight distribution of humic substances derived from municipal compost ultrafiltration and size exclusion chromatography with spectrophotometric and inductively coupled plasma-MS detection. Anal. Chem., 75, 761-767, 2003. 

Mass spectroscopic methods (MS) for T1 determination have long been known, and are extensively used in the fields of soil analysis, agricultural products, foodstuffs and biomatrices in clinical, epidemiological and occupational investigations and surveillance. Inductively coupled plasma MS (ICP-MS) is vastly superior to the previously mentioned determination methods. Indeed, quadrupole ICP-MS (Q-ICP-MS) achieves detection limits of 0.005 tg T1 in urine, whilst sector field ICP-MS (SF-ICP-MS) is... 

Chassaigne H and Lobinski R (1998a) Determination of cobalamins and cobinamides by microbore reversed phase HPLC with spectrophotometric ion-spray ionization MS and inductively coupled plasma MS detection. Anal Chim Acta 359 227-235. 

THE FUNDAMENTALS OF CAPILLARY ELECTROPHORESIS-INDUCTIVELY COUPLED PLASMA-MS... 

Spaiik ion source MS (SSMS) Secondary ion MS (SIMS) Inductively coupled plasma MS (ICP-MS) Glow discharge source MS (GD-MS) Laser-induced MS (LMS) ... 

There is much more to come, such as comprehensive capillary GC, hyphenation with time-of-flight MS (capillary GC-TOFMS) and inductively coupled plasma MS (capillary GC-ICP-MS). .. to mention a few recent technological realizations. 

The most successful hyphenated method continues to be GC/MS, generally with El ionization, but particularly the inductively coupled plasma MS (ICPMS) has become a successful detector as well. In the form of benchtop instruments, this combination is found in the chromatography laboratory rather than in mass spectrometry laboratories. Instruments such as mass selective detectors and ion traps are dedicated devices for gas chromatography and have developed into robust, dependable instruments with high detection power and selectivity. With modem computerized instruments and the extensive storage capabilities of data systems, series of spectra can be acquired rapidly, and elaborate data extraction procedures have been devised for the identification of important spectra with relevant data. 

Dual detection ion chromatography Ion chromatography/inductively-coupled plasma/MS Ion chromatography... 

Moens, L., and Jakubowski, N. (1998). Double-focusing mass spectrometers in ICPMS— From its very first days, the Achilles heel of inductively coupled plasma MS has been the number of spectroscopic and nonspectroscopic interferences. The only general method to overcome this limitation is to go to high mass resolution with a double-focusing instrument. Anal. Chem. 70(7), 251 A. 

Baca, A. J., de la Ree, A. B., Zhou, F, and Masson, A. Z. (2003) Anodic stripping voltammetry combined on-line with inductively coupled plasma-MS via a direct-injection high-efficiency nebulizer. Anal. Chem., 75, 2507-11. 

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