Determination of polymerization/coagulation in a fluid

Details Determination of polymerization/coagulation in a fluid Determination of polymerization/coagulation in a fluid

2000-11-14

2002-04-30

Chin, Christopher L. (Department: 1641)

Chemistry: analytical and immunological testing

Involving an insoluble carrier for immobilizing immunochemicals

C436S063000, C436S066000, C436S069000, C436S805000, C422S068100, C422S073000, C422S082010, C356S039000, C356S073100, C356S318000, C356S445000, C356S455000

Reexamination Certificate

active

06379976

ABSTRACT:

This is the National Stage Filing of PCT/EP99/01156 Filed on Feb. 23, 1999.
The present invention relates to the determination of polymerization/-coagulation in a fluid. More precisely, the invention relates to an analytical method of qualitative and optionally quantitative determination of the occurrence of polymerization/coagulation in a fluid containing polymerizable/-coagulable components.
BACKGROUND OF THE INVENTION
Many processes, technical as well as biological, involve polymerization/-coagulation of polymerizable/coagulable components in a fluid. Examples of such technical processes include curing of paints, lacquers, and glues; production of industrial polymers; and thickening of sauces, custards, mousses, jellies and other food stuff. Examples of such biological processes include coagulation of blood, lymph and synovial fluid, curdling of milk and gelling of agar.
The occurrence of polymerization/coagulation in a fluid has traditionally been determined with methods based on changes in optical or rheological properties of the fluid. Changes in optical properties encompass all changes in how the fluid interacts with visible and infra-red electromagnetic radiation that pass through the fluid. Changes in rheological properties denote changes in the properties of the fluid, such as viscosity, elasticity etc. For a review of prior art methods for the determination of qualitative and quantitative occurrence of polymerization/-coagulation in a fluid, see e.g. G. Odian, Principles of polymerization, Wiley Interscience, New York.
Due to convenience, economy and/or ease of performance, optical methods are often preferred, except when rheological information is specifically required. Rheological methods are used when optical methods are difficult or impossible to perform, as is the case when the fluid has poor transparency for electromagnetic rays of the required wavelength.
Poor transparency may be due either to the presence of suspended particles that scatter the electromagnetic radiation which is beamed through the fluid, or to molecular structures that absorb this radiation. For example, optical determination of the occurrence of polymerization/coagulation is difficult or impossible to use in paints, blood and milk. These, and other important fluids, have poor transparency due to scattering and absorbing pigments, cells and/or lipids. Determination of the occurrence of polymerization/coagulation in such fluids may require the use of less convenient rheological methods. Alternatively, the suspended particles and absorbing molecular structures may be removed from the fluid prior to optical determination, but such removal reduces the convenience of the method and adds uncertainty to the determination.
There are also situations when polymerization/coagulation result in virtually no change in optical properties of the fluid. Such is the case for coagulation in blood plasma from individuals with fibrinogen that forms thin fibers. The same applies to formation of jellies and other food thickening processes that involve polymerization/coagulation of large carbohydrate molecules. In situations like these, optical methods may be difficult or impossible to use, and determination of polymerization/coagulation may need to be performed with more cumbersome rheological methods.
Evidently, there is a need for analytical methods for qualitative and optionally quantitative determination of the occurrence of polymerization/-coagulation in a fluid. Such methods should preferably be as convenient as the prior art optical methods but should be applicable also in fluids with poor transparency and for occurrences of polymerization/coagulation that give rise to no or insufficient changes in the optical properties of the fluid.
It has now surprisingly been found that polymerization/coagulation in a fluid, which may be poorly transparent, can be detected and measured by methods based on changes in the surface plasmon effects which appear when a beam of electromagnetic radiation passes an interface. The surface plasmon is a longitudinal or traverse magnetic (TM) charge-density wave propagating along the interface between the two media. The surface plasmons are particularly pronounced if the interface is between an electrical conductor and a dielectric. A spectacular feature is the appearance of a surface plasmon resonance; an increased energy transfer into the surface plasmon, when a beam of electromagnetic radiation, at a certain angle and under conditions for total reflection, hits the interface. This certain angle is referred to as the surface plasomon angle. An overview of the principles of surface plasmon resonance and details on how this phenomenon may be observed and used for studies of bimolecular binding reactions when one of the binding-partners is attached to the biosensor (metal) surface are given in Liedberg B. and Lundström I., Principles of biosensing with an extended coupling matrix and surface plasmon resonance. Sensors and Actuators B. 11 (1993) 63-72, the teachings of which are incorporated herein by reference.
DESCRIPTION OF THE INVENTION
The present invention provides an analytical method of qualitative and optionally quantitative determination of the occurrence of polymerization/-coagulation in a fluid containing polymerizable/coagulable components.
A modified commercial instrument for determination of shifts in surface plasmon resonance angle was used in the experimental part of this description. When a drop of blood plasma was placed on the gold film of the instrument, relatively large effects corresponding to shifts of approximately 0.5 degrees in surface plasmon resonance angle accompanied the coagulation of the blood plasma. When the blood plasma was replaced by whole blood, similar effects were observed as the whole blood coagulated. Even larger shifts in the surface plasmon resonance angle were observed when an acryl amide dissolved in water polymerized.
The analytical method of the invention places small or no requirements on fluid volume, i.e. fluid volume size and precision in fluid transfer need not be of importance for the analytical result. This is because determinations are only effected by the fluid that is in contact with a (small) surface area and only by the fluid that is within a limited distance from this surface area. The (small) area in question is typically 1 &mgr;m
2
to 10 mm
2
and the limited distance up to about 1 &mgr;m.
The small requirements on sample volume may be an advantage in relation to the prior art optical and rheological methods which require that the fluid be in special containers, e.g. sample holders and cuvettes. This prior art requirement may be inconvenient or even hinder the determination. For example, in fluids of small volume or in fluids under severe conditions it may be difficult or impossible to properly fill the sample holder or cuvette. Examples of small-volume situations are polymerization/coagulation in a drop of blood or in a precious archeological samples. An example of severe-conditions situation is polymerization/-coagulation inside the high pressure and temperature polymerization reactor, e.g. in the production of polyethylene. On-line determinations, e.g. determinations inside flow through industrial reactors and inside the circulatory system are also difficult or impossible to perform with the prior art methods. The present invention enables determination of the occurrence of polymertzation/coagulation also in the above mentioned situations.
The present invention is in particular directed to an analytical method of qualitative and optionally quantitative determination of the occurrence of polymerization/coagulation in a fluid containing polymerizable/coagulable components, which comprises the steps of
a) initiating the polymerization/coagulation in the fluid,
b) bringing the fluid or a sample thereof into contact with a film of electrically conducting material on a support which is transparent for the electromagnetic radiation used and which is more optically dense than the fluid,
c) directing incident beams of electro

Affiliated with

Also associated with

Rating

Determination of polymerization/coagulation in a fluid does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Determination of polymerization/coagulation in a fluid, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Determination of polymerization/coagulation in a fluid will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2899450