Stop-flow analysis
First Claim
1. A method for determining the reaction speed of a sample at selected sample concentrations within a sample mixture slug comprising the steps of:
- introducing a sample into a flowing carrier stream to form a sample mixture slug having a forward head portion, a rearward tail portion and a central portion, said sample dispersing within said sample mixture slug to form reproduceable concentration gradients in said head and tail portions in which the concentration of said sample varies;
flowing said carrier stream and sample mixture slug through a measuring cell without removing the head portion or tail portion from said sample mixture slug;
stopping the flow of said carrier stream in response to a selected concentration of sample within one of said concentration gradients as said sample mixture slug passes through said measuring cell; and
measuring the reaction of said sample at said selected concentration for a period of time whereby said reaction speed of said sample at said selected sample concentration may be determined.
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Accused Products
Abstract
A continuous method of quantitatively determining slowly reacting compounds with the use of a single measuring cell, the sample being injected into a continuously flowing carrier solution which is already provided with, or simultaneously with the sample is provided with reagent to form a sample zone in the form of a reproduceable gradient. Said sample zone is led into a measuring cell whereupon the flow is stopped by means of shunting the carrier flow, by stopping the pump, or by means of a valve. The reaction is allowed to take place in the measuring cell while a magnitude, characteristic for the reaction, is registered. The reaction speed can be detected from the incline of the obtained response curve and the amount of the sought-after compounds is calculated. By means of setting the stop at a certain point in the concentration gradient curve and always selecting said point at the same time distance from the peak of the gradient curve during flow, a total reproduceability of the analysis is ensured.
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Citations
15 Claims
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1. A method for determining the reaction speed of a sample at selected sample concentrations within a sample mixture slug comprising the steps of:
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introducing a sample into a flowing carrier stream to form a sample mixture slug having a forward head portion, a rearward tail portion and a central portion, said sample dispersing within said sample mixture slug to form reproduceable concentration gradients in said head and tail portions in which the concentration of said sample varies; flowing said carrier stream and sample mixture slug through a measuring cell without removing the head portion or tail portion from said sample mixture slug; stopping the flow of said carrier stream in response to a selected concentration of sample within one of said concentration gradients as said sample mixture slug passes through said measuring cell; and measuring the reaction of said sample at said selected concentration for a period of time whereby said reaction speed of said sample at said selected sample concentration may be determined. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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- 11. In a method of analysis where a sample is introduced into a flowing carrier stream to form a sample mixture slug having a forward head portion, a rearward tail portion and a central portion, said sample dispersing to form reproducable concentration gradients in said head and tail portions in which the concentration of said sample varies, said sample undergoing a reaction while in said carrier stream, wherein the improvement comprises measuring the reaction speed of said sample at one or more selected sample concentrations within said concentration gradients by stopping the flow of said carrier stream and measuring the reaction of said sample at said selected sample concentrations for a period of time.
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13. A method of determining the change in a changing characteristic of a sample at selected sample concentrations comprising the steps of:
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introducing a sample into a flowing carrier stream to form a sample mixture slug having a forward head portion, a rearward tail portion and a central portion, said sample dispersing within said sample mixture slug to form reproduceable concentration gradients in said head and tail portions in which the concentration of said sample varies, said sample having a measureable changing characteristic; flowing said carrier stream and sample mixture slug through a measuring cell without removing the head or tail portion from said sample mixture slug;
stopping the flow of said carrier stream in response to a selected concentration of sample within one of said concentration gradients as said sample mixture slug passes through said measuring cell; andmeasuring the changing characteristic of said sample at said selected concentration for a period of time whereby the change in said characteristic of said sample at said selected concentration may be determined. - View Dependent Claims (14, 15)
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Specification