Chemistry: analytical and immunological testing – Automated chemical analysis – With aspirator of claimed structure
Patent
1996-12-11
1999-07-06
Le, Long V.
Chemistry: analytical and immunological testing
Automated chemical analysis
With aspirator of claimed structure
436 49, 436180, 422 67, 422 81, 422100, 422106, 7386302, 7386401, 7386421, G01N 3506, G01F 2328
Patent
active
059197064
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an entirely new method for sucking/determining a liquid and a pipetting device driven and controlled according to the method, and more particularly to a method for sucking/determining a liquid in which driving required for upward/downward movement of a nozzle for sucking a liquid such as a sample for a blood serum and a reagent as well as for pipetting a liquid to cylinders each for sucking and discharging the liquid is accurately controlled, so that a liquid level and a sucking rate of a liquid by the nozzle, and contamination of foreign matters therein such as bubbles or fibrins or the like in the liquid can accurately be detected, as well as to a pipetting device driven and controlled according to the method.
BACKGROUND ART
Generally, important matters required for enhancing pipetting precision are to detect a level of a blood serum sample and a reagent or similar liquid, to measure a pipetting rate thereof, to measure an absolute sucking rate thereof, to adhere the liquid to the outside of the nozzle, and to detect contamination thereof by foreign matters such as bubbles and fibrins.
For this reason, conventionally, a method has been employed, in which an electrode is immersed in the liquid together with the nozzle and the liquid level is detected according to a conductive state with the electrode so that an inserting rate (distance) of the nozzle to the liquid is controlled, but in the case of this method, the electrode must be immersed into the liquid, so that the electrode must be washed after each measurement thereof to prevent cross contamination, and as a result, there have been such problems as that a device becomes complicated, and that size and cost of the device increase.
Then, recently a method of detecting a liquid level using a pressure sensor was proposed. In this method, a sucking pressure of the nozzle when a vapor is sucked is different from that when a liquid is sucked, so that the liquid level is detected by detecting the difference between the pressures, whereby an inserting rate (distance) of the nozzle to the liquid is controlled, and for this reason only the nozzle is contacted with the liquid, and the method has such advantages as that a cleaning function is not required, which makes it possible to simplify the device as well as to reduce the costs.
However, the method of detecting a liquid level using a pressure sensor has several problems such as that the resolution is low and the sensitivity is not high, and also that the method is easily affected by an atmospheric pressure as well as by pressure change due to the sucked air, and also affected by vibrations generated due to upward/downward movement of the nozzle as well as by a noise of the pipetting device itself or a change of a voltage, and for this reason malfunction thereof occurs quite often, and the reliability thereof as a measuring means is quite low.
An optical liquid level detecting means is far more effective as a means to solve the problems as described above, and various means in which both an optical fiber for irradiating a light therethrough and an optical fiber for receiving a light are provided outside the nozzle for receiving a reflected light from a liquid level with the optical fiber for receiving a light to detect the level thereby are proposed for the liquid level detecting methods based on the conventional technology.
However, in the liquid level detecting means using a light for detecting a liquid level based on the conventional technology, in which both a fiber for irradiating a light therethrough and an optical fiber for receiving a light are provided outside the nozzle for catching a reflected light from a liquid level with the optical fiber for receiving a light to detect the level thereby, these fibers have to be inserted in parallel to each other together with the nozzle into a vessel for a liquid, and for this reason it can not be denied that the method has a possibility of cross contamination caused by the fiber contacting with the liquid ad
REFERENCES:
patent: 4844870 (1989-07-01), Rasmussen et al.
patent: 4939925 (1990-07-01), Sakuma et al.
patent: 4944922 (1990-07-01), Hayashi
patent: 5271902 (1993-12-01), Sakka et al.
Le Long V.
Precision System Science Co., Ltd.
LandOfFree
Method for sucking/determining liquid and pipetting device drive does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for sucking/determining liquid and pipetting device drive, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for sucking/determining liquid and pipetting device drive will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-898752