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Title: Freeze drying for gas chromatography stationary phase deposition

Abstract

The present disclosure relates to methods for deposition of gas chromatography (GC) stationary phases into chromatography columns, for example gas chromatography columns. A chromatographic medium is dissolved or suspended in a solvent to form a composition. The composition may be inserted into a chromatographic column. Alternatively, portions of the chromatographic column may be exposed or filled with the composition. The composition is permitted to solidify, and at least a portion of the solvent is removed by vacuum sublimation.

Inventors:
 [1]
  1. Livermore, CA
Publication Date:
Research Org.:
Sandia National Laboratories (SNL-NM), Albuquerque, NM
Sponsoring Org.:
USDOE
OSTI Identifier:
903349
Patent Number(s):
7,157,004
Application Number:
10/998,847
Assignee:
Sandia Corporation (Albuquerque, NM) SNL-A
DOE Contract Number:
AC04-94AL85000
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING

Citation Formats

Sylwester, Alan P. Freeze drying for gas chromatography stationary phase deposition. United States: N. p., 2007. Web.
Sylwester, Alan P. Freeze drying for gas chromatography stationary phase deposition. United States.
Sylwester, Alan P. Tue . "Freeze drying for gas chromatography stationary phase deposition". United States. doi:. https://www.osti.gov/servlets/purl/903349.
@article{osti_903349,
title = {Freeze drying for gas chromatography stationary phase deposition},
author = {Sylwester, Alan P},
abstractNote = {The present disclosure relates to methods for deposition of gas chromatography (GC) stationary phases into chromatography columns, for example gas chromatography columns. A chromatographic medium is dissolved or suspended in a solvent to form a composition. The composition may be inserted into a chromatographic column. Alternatively, portions of the chromatographic column may be exposed or filled with the composition. The composition is permitted to solidify, and at least a portion of the solvent is removed by vacuum sublimation.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Jan 02 00:00:00 EST 2007},
month = {Tue Jan 02 00:00:00 EST 2007}
}

Patent:

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  • A process for the preparation of amorphous precursor powders for Pb-doped Bi{sub 2}Sr{sub 2} Ca{sub 2}Cu{sub 3}O{sub x} (2223) includes a freeze-drying process incorporating a splat-freezing step. The process generally includes splat freezing a nitrate solution of Bi, Pb, Sr, Ca, and Cu to form flakes of the solution without any phase separation; grinding the frozen flakes to form a powder; freeze-drying the frozen powder; heating the dried powder to form a dry green precursor powders; denitrating the green-powders; heating the denitrated powders to form phase-clean Bi-2223 powders. The grain boundaries of the 2223 grains appear to be clean, leadingmore » to good intergrain contact between 2223 grains. 11 figs.« less
  • This invention relates to an improved process of preparing Bi-Sr-Ca-Cu-O (BSCCO) powders, and more particularly, to a process for preparing BSCCO powders that utilize freeze-drying. The process generally includes splat freezing a nitrate solution of Bi, Pb, Sr, Ca, and Cu to form flakes of the solution; grinding the flakes to form a powder; freeze-drying the frozen powder; heating the powder to form dry green precursor powders; denitrating the powders; and heating the powders to form phase-clean Bi-2223 powders.
  • A process for the preparation of amorphous precursor powders for Pb-doped Bi.sub.2 Sr.sub.2 Ca.sub.2 Cu.sub.3 O.sub.x (2223) includes a freeze-drying process incorporating a splat-freezing step. The process generally includes splat freezing a nitrate solution of Bi, Pb, Sr, Ca, and Cu to form flakes of the solution without any phase separation; grinding the frozen flakes to form a powder; freeze-drying the frozen powder; heating the dried powder to form a dry green precursor powders; denitrating the green-powders; heating the denitrated powders to form phase-clean Bi-2223 powders. The grain boundaries of the 2223 grains appear to be clean, leading to goodmore » intergrain contact between 2223 grains.« less
  • Onium salt chemistry can be used to deposit very uniform thickness stationary phases on the wall of a gas chromatography column. In particular, the stationary phase can be bonded to non-silicon based columns, especially microfabricated metal columns. Non-silicon microfabricated columns may be manufactured and processed at a fraction of the cost of silicon-based columns. In addition, the method can be used to phase-coat conventional capillary columns or silicon-based microfabricated columns.
  • The application of a dodecanethiol monolayer protected gold nanoparticle (MPN) stationary phase within a microchannel environment was explored using a square capillary column as a model for a high-speed, microfabricated gas chromatography (?GC). Successful deposition and evaluation of a dodecanethiol MPN phase within a 1.3 m long, 100?m by 100?m square capillary is reported. Depth of the MPN phase was evaluated using SEM analysis. An average thickness of 15 nm along the capillary walls was determined. While the film depth along the walls was very uniform, the corner depths were greater with the largest observed depth being 430 nm. Overall,more » an efficient chromatographic system was obtained with a minimum reduced plate height, hmin, of 1.2 for octane (k= 0.22). Characterization of the MPN column was completed using four compound classes (alkanes, alcohols, ketones, and aromatics) that were used to form a 7 component mixture with a 2 second separation. A mixture consisting of a nerve agent simulator in a sample containing analytes that may commonly interfere with detection was also separated in 2 seconds, much faster than a similar separation previously reported using a?GC system in 50 seconds. Application of the square capillary MPN column for a high-speed separation as the second column of a comprehensive two-dimensional gas chromatography system (GC x GC) was also explored. Comparison of the MPN stationary phase was compared to phases employed in previously reported?GC systems.« less