Supercritical fluid chromatography/supersonic jet spectroscopy: Progress report, 12/15/86-3/15/87

Technical Report · Thu Jan 01 04:00:00 EST 1987

OSTI ID:6542668

Goates, S R; Lee, M L

Successful linking of supercritical fluid chromatography (SFC) and supersonic jet (SJ) spectroscopy will require large but abrupt restriction without incorporating dead volumes in the nozzle which are effectively greater than a few nanoliters. We have worked on several varied nozzle designs, in addition to the types which we discussed in our last report. Pinhole nozzles still appear to offer the best type for direct supercritical fluid expansions, despite their problems with plugging. They would be especially suitable for packed column or even micro-bore SFC. We are pursuing an investigation of this nozzle type with regard to reducing problems with dead volume in the connection to the column. Several options exit for sheath nozzles which incorporate a secondary, monatomic gas expansion into which the SF/SJ is seeded. The first is the low pressure sheath flow nozzle which we have earlier described and have begun to evaluate. The main advantages to this design are that porous frit restrictors could be used to regulate the supercritical fluid flow rate, and that it may offer the best arrangement for pulsed operation. Roughly a thousand-fold enhancement in sensitivity could be expected if the SF/SJ could be pulsed synchronously with the probe laser, as is often done for gas-phase SJ. Pulsed nozzles typically are not capable of withstanding the high pressures and temperatures required with SFC and have the drawback that sudden pressure drops within the nozzle can lead to precipitation of the solute in the nozzle. Pulsing the secondary gas into the sheath region or pulsing the mixture out of the sheath nozzle would alleviate these problems. 3 figs.

• Research Organization: Brigham Young Univ., Provo, UT (USA). Dept. of Chemistry
• DOE Contract Number: FG22-86PC90534
• OSTI ID: 6542668
• Report Number(s): DOE/PC/90534-4; ON: DE87009065
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102* -- Chemical & Spectral Procedures
CHROMATOGRAPHY
DESIGN
FLUID FLOW
JETS
LASERS
NOZZLES
PULSE TECHNIQUES
RESEARCH PROGRAMS
SAMPLING
SEPARATION PROCESSES
SPECTROSCOPY
SUPERCRITICAL FLUID CHROMATOGRAPHY
SUPERSONIC FLOW