The Volumetric HPLC Sample Enrichment/Injection Valve SAMPLE SYRINGE
SAMPLE ENRICHMENT COLUMN HPLC DETECTOR
HPLC COLUMN
WASTE 2
A HPLC sample injector has two positions, one for loading and one for injection. Valeo’s new HPLC 10-port can combine the move to load position with column switching thus eliminating the need for a second valve to effect volumetric sample enrichment. The shortened rotation (36° vs. 60) compared to a standard 6-port sample valve increases the valve and the replaceable rotor’s
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VIS spectra of ions in the form of photodissociation spectra is now well established (34). More recently, acquisition of partial infrared spectra of ions has been accomplished using multiphoton absorption from an IR (CO2) laser (35). These methods should be adaptable to mixture analysis in an MS/MS mode simply by adding suitable high-amplitude pulses to eject unwanted ions from the cell prior to the activation. The exceptional mass resolution of FTMS may make it the method of choice for analysis of high molecular weight materials. There is no mass discrimination inherent in the FTMS detection scheme. The ultrahigh resolution at low mass extrapolates to reasonable resolution at high mass. For example, a resolution of 800 000 at m/z 78 and 1.2 T becomes 8000 at m/z 7800. Increasing the magnetic field by a factor of 10 should permit m/z 7800 to be observed with a resolution of 80 000. Of course, this can only be accomplished if high molecular weight materials can be volatilized and ionized. Pulsed laser desorption, which is compatible with the pulsed FTMS detection, may be appropriate. Fast atom bombardment is another possibility for volatilization of materials that are ionic in the solid state. Advances in FTMS are tied directly to progress in electronics and computers, both of which have been highgrowth technologies. For example, we should expect the addition of sensitive broad-band amplifiers for improving S/N ratios and array processors for doing real-time Fourier transforms in the near future. In conclusion, we point out that the experiments done to date are of a demonstration nature and represent efforts to develop methodology. The real test for FTMS will come when analytical chemists have access to these instruments and apply them to real analytical problems.
Acknowledgment We are particularly indebted to
our
co-workers Sahba Ghaderi, E.B. Ledford, R. L. White, and R. B. Spencer for the progress we’ve made in analytical FTMS. We also thank R. T. Mclver, Jr., and . M. Bursey for helpful comments on this manuscript.
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References (1) Henis, J. M. S. Anal. Chem. 1969,41 (10), 22-32 A. (2) Gross, M. L.; Wilkins, C. L. Anal. Chem. 1971, 43 (14), 65-68 A. (3) Wilkins, C. L. Anal. Chem. 1978,50, 493-500 A. (4) Mclver, R. T., Jr. Am. Lab. 1980,12, 18-30. (5) Comisarow, . B.; Marshall, A. G. Chem. Phys. Lett. 1974,25, 282-83. (6) Comisarow, . B.; Marshall, A. G. Chem. Phys. Lett. 1974,26, 489-90. (7) Comisarow, . B.; Marshall, A. G. Can. J. Chem. 1974, 52,1997-99.
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