Continuous flow analyzing method and apparatus

• US 5,624,846 A
• Filed: 04/28/1995
• Issued: 04/29/1997
• Est. Priority Date: 04/28/1994
• Status: Expired due to Term

• Current Assignee: Mitsubishi Materials Corporation
• Original Assignee: Mitsubishi Materials Corporation
• Inventors: Hayashibe, Yutaka, Sayama, Yasumasa
• Primary Examiner(s): Soderquist, Arlen
• Application Number:
  US08/430,735
• Time in Patent Office: 732 Days
• Field of Search: 422/62, 422/81, 422/82, 422/108, 436/52, 436/55, 436/73, 436/81, 436/166, 436/172, 436/175, 436/177, 436/178, 436/50
• US Class Current: 436/50
• CPC Class Codes: G01N 35/085 Flow Injection Analysis
• CPC Class Codes: Y10T 436/115831 Condition or time responsive
• CPC Class Codes: Y10T 436/117497 with a continuously flowing sample or carrier stream
• CPC Class Codes: Y10T 436/12 Condition responsive control
• CPC Class Codes: Y10T 436/200833 Carbonyl, ether, aldehyde or ketone containing
• CPC Class Codes: Y10T 436/25125 Digestion or removing interfering materials
• CPC Class Codes: Y10T 436/25375 Liberation or purification of sample or separation of material from a sample [e.g., filtering, centrifuging, etc.]

Abstract

A continuous flow analyzing method and an apparatus for carrying out the analyzing method wherein a sample is injected in a continuously flowing carrier and the sample is introduced into a detector by the carrier to thereby perform a quantitative analysis contained in the sample. In the method the sample to be analyzed is filled into a sample introduction switchover valve (SISV); a portion of the sample from the SISV is injected into the carrier and an analysis of this sample is conducted to obtain a detection peak for the analyzed sample. These steps are repeated and the sample is continuously analyzed by, in the case where a detection peak obtained in the detector is under an optimum analysis range, increasing an injection amount of the sample, and in the case where the detection peak obtained in the detector is over the optimum range, decreasing the injection amount of the sample. Adjustment of the detection peak is repeated until the detection peak reaches the optimum analysis range. Since it is possible to precisely control the injection amount of the sample, it is possible to conduct a high precision quantitative analysis. It is possible to apply the method to a sample having a concentration as low as about 1 ng/ml up to a concentration as high as about 1,000 μg/m with the same apparatus system by feeding the results obtained in a detector back to a sample feed system.

Claims

1. A continuous flow analyzing method wherein a sample is injected in a continuously flowing carrier and the sample is introduced into a detector by the carrier to thereby perform a quantitative analysis of the sample, comprising the steps of:

a) filling a sample introduction switchover means with the sample to be analyzed;

b) introducing a partial amount of the sample from the sample introduction switchover means into the carrier;

c) analyzing said amount of the sample from b) in the detector to determine a detection peak;

d) comparing the detection peak obtained in the detector with a predetermined optimum analysis range;

e) continuously analyzing the sample by repeating steps b), c) and d) until the detection peak reaches the optimum analysis range and, in the case where the detection peak obtained in the detector is under the optimum analysis range, increasing the amount of the sample introduced into the carrier, and in the case where the detection peak obtained in the detector is over the optimum analysis range, decreasing the amount of the sample introduced into the carrier.

2. The continuous flow analyzing method according to claim 1, further comprising the steps of:

in the case where the sample introduction switchover means is opened so that the sample in the sample introduction switchover means is extruded into the flow of the carrier by carrier that is introduced into the sample filling portion,

increasing or decreasing the amount of the sample by increasing or decreasing the opening time of said sample filling portion and/or a flow rate of the carrier.

3. The continuous flow analyzing method according to claim 1, further comprising the step of:

providing a step for concentrating a component of the sample to the measured between the sample injection step and the detection step so that the quantitative analysis is conducted after increasing the concentration.

4. The continuous flow analyzing method according to claim 3, wherein said concentrating step includes adsorbing the component to be measured in an adsorbing means provided between the output of the sample introduction switchover means and the detector, and eluting the component to be measured from the adsorption portion, wherein the component to be measured is eluted and introduced to the detector after concentration of the component by repeating said adsorbing step.

5. A continuous flow analyzing apparatus wherein a sample is introduced into a continuously flowing carrier and the sample is introduced into a detector by the carrier to thereby perform a quantitative analysis, comprising:

a detector;

a flow path for introducing into the detector, a continuous flow of the carrier formed by a liquid feed pump; and

a sample introduction switchover means interposed in said flow path,

wherein said sample introduction switchover means has a sample filling portion for holding a predetermined amount of the sample to be analyzed, and a switchover valve for opening and closing the sample filling portion relative to the continuous flow, and wherein said sample introduction switchover means and said detector are connected to each other by a control means for controlling the opening and closing time of the switchover valve to introduce a partial amount of the sample in the sample filling portion into the flow path in response to a detection peak of the sample that is obtained by said detector, whereby a feed back function is performed such that an amount of the sample introduced into said carrier is increased or decreased in response to the detection peak.

6. The continuous flow analyzing apparatus according to claim 5, further comprising a means for concentrating the component to be analyzed, which is contained in the sample, said means being interposed in the flow path between said sample introduction switchover means and said detector.

7. The continuous flow analyzing apparatus according to claim 6, wherein said concentrating means comprises an ion-exchange column.

8. The continuous flow analyzing apparatus according to claim 5, further comprising:

a pretreatment column for converting a nonionic component containing the sample into a soluble component having an ionic property.

9. The continuous flow analyzing apparatus according to claim 8, wherein said pretreatment column is a pretreatment reaction column for reacting the sample to be analyzed with sulfuric acid or nitric acid.