Optics: measuring and testing – Sample – specimen – or standard holder or support – Fluid containers
Patent
1984-12-18
1987-05-26
McGraw, Vincent P.
Optics: measuring and testing
Sample, specimen, or standard holder or support
Fluid containers
73 231, G01N 110
Patent
active
046680918
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to an arrangement at a gas flow cell for spectrophotometric analysis of chemical compounds in the gas phase consisting of a longitudinal preferably cylindrical body with a longitudinal central channel which at both ends of the body is limited by two mutually parallel windows which are tighfitting against the channel and transparent for the radiation used at the analysis, which channel communicates at one end with connections for a carrier gas and for injecting compounds and at the other end has an outlet for the compounds and the carrier gas.
BACKGROUND OF THE INVENTION
That part of analytical chemistry which is dealing with separation and detection of organic compounds in mixtures has ever since in the sixties been dominated by gas chromatography where the detection normally is obtained by an unspecific detector. More recently the technique has developed towards combinations of gas chromatography (GC) with qualitative analytical methods like mass spectroscopy (MS), IR-spectrophotometry (IR) or UV-spectrophotometry (UV). The advantage with these combinations is first of all that it gives possibilities for identification of compounds which are separated on the gas chromatograph. Further on it gives the possibility to achieve selective detection for example by selecting a wavelength on the UV- or IR-detector where only aromato compounds gives a response.
DRAWBACKS OF KNOWN TECHNIQUE
Gas chromatographs has in general a size and complexity which imply that the instrument must be permanently installed in one place. The injector, column and detector are further on individually heated and the possibilities for identification of an unknown compound is strongly restricted with conventionel instruments equipped with unspecific detectors. Additional drawbacks are lengthy start up times, occasionally relatively long analysis times and high instrument costs.
Commersially available instrument combinations exist for GC/IR and for GC/MS but not for GC/UV. The commercial combination of instruments are very costly and have complicated connections between the gas chromatograph and the spectrophotometer which makes it considerably difficult for changing to other analytical techiques like IR-analysis of compounds in the liquid phase. The high costs and the complexity has led to that most analytical laboratories with a particularly quantitative direction will have restricted possibilities for identification of compounds.
OBJECT OF THE INVENTION
A primary object of the invention in question is to achieve a gas flow cell by initially described kind, by which the combinations GC/UV and GC/IR as well as enrichment of compounds can be carried out.
This is obtained according to the primary characteristic of the invention in that there is a second channel serving for separation connected between the connections and one of the ends of the first mentioned channel, in which channel there is replaceable column with column filling of a kind known per se.
In that the body, according to a special characteristic of the invention, is of an electrically leading polymeric material of a temperature self-regulating quality and has electric connections so that the body can be heated by connection to a voltage supply is obtained that through utilization of the body as a resistor element with temperature self-regulating characteristic depending on increasing resistance with increasing temperature the cell can be heated in a way that a good separation of the compounds is achieved.
SHORT DESCRIPTION OF THE DRAWING
In the following the invention will be further explained with reference to the attached drawing on which
FIG. 1 in perspective shows a gas flow cell according to the present invention.
FIG. 2 shows a longitudinal section through the gas flow cell in FIG. 1 and
FIG. 3 and 4 show one of the ends of the gas flow cell seen in axial direction respectively across this direction.
DESCRIPTION OF AN EMBODIMENT
On the drawing numeral 1 represents a longish preferably cylindrical body with a longitudinal cent
REFERENCES:
patent: 3778156 (1973-12-01), Schmedes et al.
patent: 3919279 (1974-06-01), Braun et al.
"Vergleich von Atomabsorption und Atomfluoreszenz in der Graphitkuvette", H. Massman, Spectrochimica Acta, 1968, vol. 23B, pp. 215-226, Pergamon Press, Northern Ireland.
"The Potentialities of the Graphite Crucible Method in Atomic Absorption Spectroscopy", B. L. L'vov, Spectrochimica Acta, vol. 24B, pp. 53-70, Pergamon Press 1969, Northern Ireland.
"The Analytical Use of Atomic Absorption Spectra", B. V. L'Vov, Spectrochimica Acta, 1961, vol. 17, pp. 761-770, Pergamon Press Ltd., Northern Ireland.
"Analysis by Means of Atomic-Absorption Spectroscopy, Using a Tantalum Boat", H. V. Lagesson, The Lund Institute of Technology, Chemical Center, Box 740, Lund 7, Sweden, pp. 527-538.
"Present State and the Main Problems of Atomic Absorption Analysis--A Review", B. V. L'Vov, State Institute of Applied Chemistry, Leningrad, translated from Zhurnal Analiticheskoi Khimil, vol. 26, No. 3, pp. 590-608, Mar. 1971 (1971 Consultants Bureau, Division of Plenum Publishing Corporation, New York, New York, pp. 510-529).
Lagesson Verner
Lagesson-Andrasko Ludmila
McGraw Vincent P.
Turner S. A.
LandOfFree
Arrangement at a gas flow through cell for spectrophotometric an does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Arrangement at a gas flow through cell for spectrophotometric an, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Arrangement at a gas flow through cell for spectrophotometric an will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-700129