Surgery – Diagnostic testing – Measuring or detecting nonradioactive constituent of body...
Reexamination Certificate
1998-01-30
2001-02-06
O'Connor, Cary (Department: 3736)
Surgery
Diagnostic testing
Measuring or detecting nonradioactive constituent of body...
Reexamination Certificate
active
06183418
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process and a measuring system for detection of substances emitted or perspired through the skin, in particular alcohol, by means of a detection system responding to the substances.
2. Background Description
Precisely in the fields of foodstuff analysis and medicine, there is a constant need for new, easy to handle, reliable analyzing methods for detection of the widest variety of substances. In some fields of application there is also the need for the related analyzing equipment to be easy to transport, to make on-site analysis possible. In addition, the criterion of cost often plays a role, and for this reason, processes and measuring equipment that are particularly inexpensive to operate are also in demand.
For traffic control by the police, a simple, reliable and adequately precise test for a quick assessment of blood alcohol level during road checks is still being sought. The test for blood alcohol level via the breath conducted thus far firstly presupposes the active cooperation of the driver and in addition, it can be considerably distorted by numerous outside influences.
The technical problem on which the invention is based consists in first finding in general, a reliable, easy to handle, sufficiently precise analyzing process for quantitative determination of small quantities of substances in a solution or in a gas phase with suitable detectors, that is appropriate to indirectly determine the blood alcohol level.
A further technical problem of the invention consists in developing for this process a measuring system that is as transportable as possible, and easy and safe to operate.
SUMMARY OF THE INVENTION
According to an aspect of the invention, this technical problem is solved by a transportable measuring system for detection of substances emitted or perspired through the skin, by flow diffusion analysis, by means of a detection system responding to these substances, whereby the flow diffusion analysis unit arranged in the measuring system consists of:
means for stocking up and conveying an acceptor solution (
50
,
10
,
20
,
30
,
70
),
means for controlling the volume flow of the acceptor solution (
40
,
60
,
200
),
a diffusion analysis half cell (
80
), consisting of a chamber for receiving the acceptor solution and a membrane (
81
) closing this chamber and permeable to the substance to be detected,
a chamber designed in front of the membrane and open toward the outside for forming a closed gas volume between the skin and the membrane under measuring conditions,
a detection system (
90
) for detection of the substance to be detected, and
means for evaluating and displaying the measuring results.
According to another aspect of the invention, the technical problem is solved by a transportable measuring system for detection of substances emitted or perspired through the skin, by flow diffusion analysis, by means of a detection system responding to these substances, whereby the flow diffusion analysis unit arranged in the measuring system consists of:
means for stocking up and conveying an acceptor solution (
50
,
10
,
20
,
30
,
70
),
means for controlling the volume flow of the acceptor solution (
40
,
60
,
200
),
a diffusion analysis half cell (
80
), consisting of a chamber for receiving the acceptor solution and a membrane (
81
) closing this chamber and permeable to the substance to be detected,
a detection system (
90
) for detection of the substance to be detected,
means for evaluating and displaying the measuring results, and
a replaceable part (measuring head) that comprises the membrane (
81
), with parts of the flow diffusion analysis unit.
Furthermore, the technical problem is solved by a process for detection of substances emitted or perspired through the skin, in particular alcohol, by means of a detection system by flow diffusion analysis, responding to these substances, whereby for the duration of the sampling, a membrane arranged in a replaceable measuring head is placed directly onto the skin of a person to be examined or is brought into contact with a closed gas volume formed over the skin, whereby a diffusion half cell is used which is closed with the membrane and through which an acceptor medium flows, and whereby the acceptor solution loaded with the substance to be detected is fed to the detection system.
With the modified flow diffusion analysis presented in this case, it is a matter of a process derived from the known flow diffusion analysis.
In this connection, the known process of flow diffusion analysis is modified in such a way that the membrane of a diffusion half cell through which acceptor medium flows is brought directly into contact with a skin surface evaporating/perspiring the substance or a gas volume formed over the skin.
A quantity of alcohol correlating to the blood alcohol level is emitted through the skin and is measured there by placing the membrane of the half cell onto the skin.
The principle of flow diffusion analysis is known for the example of an ethanol concentration determination in beer and wine, it is described in: J. Mohns, W. Kuennecke, “Deutsche Lebensmittel-Rundschau”,
German foodstuff review,
92nd year (1996), pp. 1-4.
The setup described therein for the flow diffusion analysis consisted of a 2-channel pump, two 3/2-port directional valves, a tempered diffusion cell with hydrophobic gas diffusion membrane, an enzyme reactor, a thick-layer electrode in a “wall jet” flow cell, and a potentiostat for electrochemical detection. The control and data recording takes place via computer. The principle of conventional FDA consists in that a continuous donor stream (sample/standard) is conveyed at a specific rate of flow through the diffusion cell (tempered if necessary), while an acceptor flow (in the example 0.1 in potassium phosphate buffer pH 7.5) is pumped at the same rate of flow on the other side of the membrane through the diffusion cell. For the analysis, in general the acceptor flow is stopped in the diffusion cell for a certain period of time by switching the valves, in such a way that the substance to be measured, ethanol in this case, can diffuse through the membrane from the donor flow into the acceptor medium. The quantity of ethanol diffused through the membrane is dependent on the layer thickness/pore size of the membrane, the stopping time (accumulation time) and the concentration gradient over the membrane. After switching the valves again, the volume element enriched with ethanol in the acceptor is further conveyed to the detection.
The described principle of flow diffusion analysis has the disadvantage that the donor flow must be separately controlled, necessitating a more expensive setup in terms of equipment. For this reason, flow diffusion analysis is less suitable for quick tests on different samples.
From DE 41 25 739 A1, a device and a process are known for sampling and measuring samples from a number of different measuring points; this is intended and suitable for the monitoring of air in a space. Samples are taken at different collecting points in the space, at which the air samples are introduced via valves or membranes into a collecting pipe and inside it, they are fed with a carrying medium to a sensor. In the case of this system. it is a matter of a large, stationary system, such that the principles of the related process cannot easily be transferred to a transcutaneous blood alcohol measurement on the skin of a test subject.
From DE 33 09 458 A1, a measuring process is also known for the concentration of combustible components in a liquid or a gas; in it, a sampler of a membrane permeable to gas, for example a plastic hose, is inserted into the gas chamber of a reactor boiler and combustible components diffusing in are fed to a semiconductor gas sensor with pure oxygen as carrier gas. In this case as well, only a purely stationary system is described.
From DE 31 37 765 A1, a process and a system are known for quick detection, identification and quantification of trace elements in gases,
Astorino Michael
McGuire, Woods, Battle & Boothe, LLP
O'Connor Cary
Trace Analysensysteme GmbH
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