The present invention relates generally to a technique for deciding whether the concentration of a repeatedly used antiseptic solution, such as a glutaral or phtharal solution, is adequate for reuse and, more particularly, to method and equipment for quantitatively detecting the concentration of such antiseptic solutions.
At present, the glutaral and phtharal solutions, which are high-level antiseptic solutions widely used in hospitals or similar medical facilities, are not disposed of after each use but instead they are usually stored for reuse in many cases. Accordingly, these antiseptic solutions are inevitably deteriorated by secular changes after opening their sealed packages or they are diluted by the mixing thereinto of water that often adheres to objects of disinfection during their cleaning and rinsing prior to disinfection—this lowers the concentrations of components effective for disinfection, often resulting in a failure of appropriate disinfection. Hence, the use of such antiseptic solutions calls for accurate measurement of their concentrations.
Conventionally, the concentration of such antiseptic solution is measured by colorimetry using test strips offered by antiseptic-solution makers, spectrometry, liquid chromatography, or the like. The colorimetry using test strips is simple and hence easy, but it is very difficult with this method to measure the concentration of the antiseptic solution on the borderline between adequate or low; in some cases, the use of the antiseptic solution is abandoned for safety reasons despite its adequate concentration, or an error in measurement may sometimes allow the use of an antiseptic solution of a concentration lower than the adequate value. The spectrometry and the liquid chromatography are both defective in that their measuring equipment is expensive and difficult to handle and consumes much time for measurement. From the economical point of view, it is disadvantageous to install such measuring equipment in hospitals or similar medical facilities for only measuring the concentration of the antiseptic solution.
The present invention is intended to solve the above-described problems of the prior art, and has for its object to provide a method and equipment for easy, simple, economical and accurate measurement of concentrations of glutaral, phtharal and similar antiseptic solutions.
To attain the above objective, the method for measuring the concentration of an antiseptic solution according to claim 1 of this application is characterized by the steps of electrically measuring the absorbance of the antiseptic solution, such as a glutaral or phtharal solution, by a photodetector to detect its absorbance of ultraviolet rays; and calculating, by a computer, a function of proportionality between the measured ultraviolet absorbance of the antiseptic solution and pre-measured ultraviolet absorbance of an undiluted antiseptic solution and a function of proportionality between the ultraviolet absorbance and concentration of the undiluted antiseptic solution.
The method for measuring the concentration of an antiseptic solution according to claim 2 of this application is characterized by: measuring the temperature of the antiseptic solution, such as a glutaral or phtharal solution, by a thermometer; electrically measuring the absorbance of the antiseptic solution by a photodetector to detect its absorbance of ultraviolet rays; and calculating, by a computer, a function of proportionality between the ultraviolet absorbance of the antiseptic solution and pre-measured ultraviolet absorbance of an undiluted antiseptic solution and a function of proportionality between the ultraviolet absorbance and concentration of the undiluted antiseptic solution.
The method for measuring the concentration of an antiseptic solution according to claim 3 of this application, which is a modification of the method of claim 1 or 2, is characterized by the steps of: pouring an unused antiseptic solution and pure water into the optical cell separately of each other; calibrating, by a computer, electrical signals from the optical cell which represent the ultraviolet absorbance and concentration of the undiluted antiseptic solution and the pure water, respectively; and calibrating concentration measuring equipment based on the calibrated values.
Equipment for measuring the concentration of an antiseptic solution according to claim 4 of this application is characterized by: an optical cell for containing an antiseptic solution under measurement; a light-emitting part for irradiating the antiseptic solution in said optical cell with ultraviolet rays; a light-receiving part provided outside the optical cell, for receiving ultraviolet rays partly absorbed by the antiseptic solution in proportion to the concentration thereof, for detecting the ultraviolet absorbance of the antiseptic solution from the intensity of the received ultraviolet rays, and for generating an electrical signal representing the ultraviolet absorbance of the antiseptic solution; a computer for calculating the concentration value of the antiseptic solution by calculating the relationships between the electrical signal and pre-input electrical signals representing the ultraviolet absorbance and concentration of an undiluted antiseptic solution; and a display for displaying the concentration value calculated by the computer.
Equipment for measuring the concentration of an antiseptic solution according to claim 5 of this application is characterized by: an optical cell for containing an antiseptic solution under measurement; a light-emitting part for irradiating the antiseptic solution in the optical cell with ultraviolet rays; a light-receiving part provided outside the optical cell, for receiving ultraviolet rays partly absorbed by said antiseptic solution in proportion to the concentration thereof, for detecting the ultraviolet absorbance of the antiseptic solution from the intensity of the received ultraviolet rays, and for generating an electrical signal representing the ultraviolet absorbance of the antiseptic solution; a thermometer for measuring the temperature of the antiseptic solution in the optical cell, and for converting said measured temperature to the corresponding electrical signal; a computer for calculating the concentration value of said antiseptic solution by calculating the relationships between the electrical signals representing the ultraviolet absorbance and temperature of the antiseptic solution and pre-input electrical signals representing the absorbance and concentration of an undiluted antiseptic solution; and a display for displaying the concentration value calculated by the computer.
The equipment for measuring the concentration of an antiseptic solution according to claim 6 of this application, which is a modification of claim 4 or 5, is characterized in that: an unused antiseptic solution and pure water are separately poured into the optical cell; electrical signals from the optical cell which represent the ultraviolet absorbance and concentration of the unused antiseptic solution and the pure water, respectively, are calibrated by the computer; and the measuring equipment is calibrated accordingly.
The measurement of the concentration of the antiseptic solution according to the method of the present invention begins with electrical detection of the ultraviolet absorbance of the antiseptic solution by a photodetector. Then, the concentration of the antiseptic solution is accurately detected from the function of proportionality between the measured ultraviolet absorbance of the antiseptic solution and pre-measured ultraviolet absorbance of an undiluted antiseptic solution and the function of proportionality between the ultraviolet absorbance and concentration of the undiluted antiseptic solution.
Further, measurement of the temperature of the antiseptic solution by a thermometer is followed by electrical detection of the ultraviolet absorbance of the antiseptic solution. And, the function of proportionality between the measured ultraviolet absorbance of the antiseptic solution and pre-measured ultraviolet absorbance of an undiluted antiseptic solution and the proportional relation between the ultraviolet absorbance and concentration of the undiluted antiseptic solution are calculated by a computer to accurately detect the concentration of the antiseptic solution.
Prior to the measurement of concentration, an unused antiseptic solution and pure water are poured into the optical cell, and electrical signals from the optical cell, corresponding to the unused antiseptic solution and the pure water, respectively, are used to calibrate concentration measuring equipment. This ensures accurate measurement of the concentration of he antiseptic solution without being affected by external disturbance.
According to the antiseptic-solution concentration measuring equipment of the present invention, the antiseptic solution under measurement is poured into an optical cell, and the ultraviolet absorbance of the antiseptic solution is detected by a photodetector. That is, the photodetector receives ultraviolet rays partly absorbed by the antiseptic solution in proportion to its concentration, then detects the ultraviolet absorbance of the antiseptic solution, and outputs an electrical signal representative of the concentration of the antiseptic solution. The temperature of the antiseptic solution in the electrical cell is measured, as required, by a thermometer and converted to the electrical signal corresponding to the measured temperature. The concentration of the antiseptic solution is calculated by the computer from the relationship between the pre-input electrical signals indicating the ultraviolet absorbance and concentration of the undiluted antiseptic solution, coupled with the electrical signal fed from the thermometer, and the concentration thus detected is displayed on the display.
Prior to the measurement of concentration, an unused antiseptic solution and pure water are poured into the optical cell, and the electrical signals fed therefrom corresponding to antiseptic solution and the pure water are used to calibrate the measuring equipment to ensure accurate measurement of the concentration of the antiseptic solution without being affected by external fluctuation or disturbance.
The present invention permits easy and simple measurement of the concentration of an antiseptic solution and miniaturization of the equipment therefor as compared with the conventional spectrometry. Furthermore, the present invention permits reduction of the amount of antiseptic solution under measurement, and hence suppresses exposure by the antiseptic solution. With the thermometer mounted on the concentration measuring equipment, it is possible to correct and calibrate the temperature characteristic or dependence of the ultraviolet absorbance of the antiseptic solution. Moreover, the calibration of the measuring equipment by use of an unused antiseptic solution ensures high and reliable measurement accuracy.
A description will be given, with respect to the accompanying drawings, of the method and apparatus for measuring the concentration of an antiseptic solution according to Embodiment 1 of the present invention.
Referring first to
A detailed configuration and function of the concentration measuring apparatus 100 will be described below in more detail. As shown in
The light-emitting part 5 is formed, for example, by an LED element that emits ultraviolet rays.
The antiseptic-solution concentration measuring equipment 100 of the above configuration conducts the measurement of the concentration of the antiseptic solution S such as the glutaral and phtharal solutions. A description will be given of measuring functions of the equipment. In the first place, the antiseptic solution S to be measured is poured into the optical cell 1, and the ultraviolet absorbance of the antiseptic solution S is detected by the light-receiving part 9 that receives the ultraviolet rays G emitted from the light-emitting part 5. That is, the light-receiving part 9 receives the ultraviolet rays G′ partly absorbed by the antiseptic solution S in proportion to its concentration, detects the ultraviolet absorbance of the antiseptic solution S, and outputs the electrical signal E1. The temperature of the antiseptic solution S in the optical cell 1 is measured by a thermometer and converted to the electrical signal E2. Based on the relationships between the electrical signals E1 and E2 and the prestored calibration curves, the computer CPU calculates the concentration N of the antiseptic solution S, which is displayed on the display 20.
Incidentally, prior to the above-described measurement of concentration, an used or new antiseptic solution S and pure water W are poured into the optical cell 1, then electrical signals corresponding to them, respectively, are input to the computer CPU, which uses them to perform calibration, thereby ensuring accurate measurement of the antiseptic solution S without being affected by external disturbance.
Next, a description will be given below of calibration and concentration measuring methods by the antiseptic-solution concentration measuring equipment 100. The calibration according to a first embodiment of the invention is carried out as shown in
Next, the calibration method according to a second embodiment of the invention will be described with reference to
In the first place, prepare an antiseptic solution (the indicated concentration of a commercially available undiluted antiseptic solution is assumed as positive) and water (of 0% concentration). In step A1, “measure the transmittance of an empty optical cell {record the output value (Ref. 1)}. In step A, “pour the undiluted antiseptic solution into the optical cell and measure the absorbance of the antiseptic solution.” In step B, “record the output voltage (V1).” In step C, “remove the antiseptic solution from the optical cell.” In step C1, “compute V1/Ref. 1.” In step A2, “measure the transmittance of the empty optical cell {record the output value (Ref. 2)}. In step D, “pour water (of 0% concentration) into the optical cell and measure the absorbance of the water.” In step E, “record the output voltage (V2).” In step F, “remove the water from the optical cell.” In step H, “plot the calibration curve K2 by a linear expression based on the relationship between concentration and V1/Ref. 1 In
Next, the calibration method according to a third embodiment of the invention will be described with reference to
[Example of Measurement]
(1) “Put calibration cell A (of A % concentration) in optical cell,” then “Measure transmittance or absorbance of calibration cell A,” then “Output voltage,” and “Record output voltage (V1).”
(2) “Put calibration cell B (of B % concentration) in optical cell,” then “Measure transmittance or absorbance of calibration cell B,” then “Output voltage,” and “Record output voltage (V2).”
The calibration method according to a fourth embodiment of the invention will be described with reference to
The calibration of the measuring equipment is followed by the measurement of the concentration of used antiseptic solution.
(1) The simplest concentration measuring method begins with pouring the used antiseptic solution S of unknown concentration into the optical cell 1, followed by recording the output voltage E1 fed from the light-receiving part 9. The concentration of the used antiseptic solution can be inferred from the calibration curve K1 shown in
(2)
(3) This method automates the computation of the calibration curve K1 or K2 in
(4) Furthermore, each of the above-described measuring methods measures the temperature of the antiseptic solution by the thermometer 3 mounted in the optical cell 1 to compensate for variations in the transmittance (or absorbance) by temperature, providing increased accuracy in the concentration measurement.
As described above, the mode of working of the present invention produces such effects as mentioned below. The measuring method of the present invention is very simple and easy as compared with the conventional spectrometry and the measuring equipment is also smaller than in the past. Since the amount of antiseptic solution necessary for measurement is small, exposure by the antiseptic solution can be reduced. And, the thermometer mounted in the measuring equipment enables the temperature characteristic of the absorbance to be corrected and calibrated. Furthermore, the calibration of the measuring equipment by use of unused antiseptic solution increases the measurement accuracy and enhances its reliability.
Incidentally, the present invention should not be construed as being limited specifically to the above-described embodiments. For example, individual configurations of the light-emitting part 5, the light-receiving part 9 and the optical cell 1 and their associated arrangements, and the system of the display 10 can be properly modified.
The present invention has been described as being applied to the measurement of the concentration of the antiseptic solution, but the invention is not limited specifically thereto and is applicable to various other concentration measurements.
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Number | Date | Country | Kind |
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2003-302830 | Aug 2003 | JP | national |