JP2002214105A - Volatile component quantity measuring device and volatile component quantity measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device and a method for easily measuring a plurality of volatile component quantities in an object. SOLUTION: This volatile component quantity measuring device for evaporating the volatile components in the object by decompression, and measuring the volatile component quantities in the object from the weight difference before and after evaporation is characterized by being equipped with a data processing device for operating evaporation speed from a weight change curve during decompression, and operating simultaneously the constitutional ratio between a plurality of components having different evaporation speeds based on its inflection point.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring a plurality of volatile components such as a water content in an object. In particular, it is an object of the present invention to provide an apparatus which can be applied when a simple measurement of the composition is required in a mixed system of water and a highly volatile organic solvent.

[0002]

2. Description of the Related Art As a method for measuring the amount of volatile components in an object, a chemical method such as chromatography or moisture titration or an optical method such as infrared spectroscopy is generally used. These methods are excellent in that specific volatile components can be quantified.However, there are many restrictions on the shape and transparency and other properties of the object, and complicated pretreatment is required. In many cases, it is not appropriate in fields where time measurement is required.

[0003] Many methods have been proposed for easily detecting changes in the amount or ratio of volatile components with respect to moisture. However, when roughly classified according to the characteristics to be measured, the absorption intensity at a specific wavelength of infrared light is used as an index. Method Method using index of short-wavelength electromagnetic waves such as microwaves as an index Method using index of change in dielectric constant Method using index of change in conductivity Method using index of change in density Method using index of change in weight Other Can be divided into methods using the change in the characteristics of the index as an index. Among them, the method using the change in weight as an index is the most direct method for measuring the amount, and the method is widely used as the most general method because the total amount of volatile components can be measured without depending on the type.

In this method, the weight of a volatile component is determined from the difference before and after the removal of the volatile component. Method of removing by vaporizing by heating Method of removing by volatilizing by vibration Method of removing by promoting evaporation by reducing atmospheric pressure Method of waiting for natural evaporation at atmospheric pressure

[0005] These methods are one of the widely used methods because the total amount of volatile components can be statically and simply measured. However, the total amount and ratio of a system composed of a plurality of volatile components are simultaneously measured. Was difficult.

[0006]

In the gravimetric method (decompression method) in which the evaporation is promoted by lowering the atmospheric pressure of the atmosphere, the end point is determined at the time when the weight loss is no longer lost, so that the total amount of the volatile components can be reliably measured. However, the composition ratio of each of the constituent components of the system composed of a plurality of components could not be grasped by this method alone. In the case of a single volatile system, if the total amount of volatiles is known, the volatile content ratio in the sample can be determined, so there is no problem with this.However, in the actual process, multiple volatile components are often used in combination. Variations in component ratios have often been problematic.

As a method for specifying the amounts of the respective components, the above-mentioned methods such as chromatography are not impossible. However, since the method is generally time-consuming and complicated, a method of simultaneously obtaining the total amount and the composition ratio of the volatile components by a decompression method. And the equipment was required.

The present invention has been made to solve this problem, and has as its object to provide an apparatus and a method for easily measuring a plurality of volatile components in an object.

The rate of weight loss due to evaporation of a plurality of volatile components is the sum of the weight loss due to evaporation of each component, so the rate of weight loss under reduced pressure is determined by the evaporation rate of each component determined by the temperature of the atmosphere and the vapor pressure. However, it is difficult to accurately determine the component amount by predicting these factors because the actual measured value of the weight change includes other factors such as a decrease in the surface area due to the progress of evaporation.

The present inventor has studied in detail the weight loss behavior of a mixture of a plurality of volatile components under reduced pressure. A speed change point appears,
It was confirmed that the weight loss at this time coincided with the abundance ratio of the component having a high evaporation rate in the sample, and the apparatus of the present invention was completed.

[0011]

According to a first aspect of the present invention, there is provided a volatile component for evaporating a volatile component in an object under reduced pressure and measuring the amount of the volatile component in the object from a weight difference before and after the evaporation. The mass measuring device includes a data processing device that calculates an evaporation rate from a weight change curve during decompression, and simultaneously calculates a composition ratio of a plurality of components having different evaporation rates based on the change point. It is a volatile component amount measuring device.

According to a second aspect of the present invention, there is provided a method for measuring the amount of volatile components in an object by evaporating the volatile components in the object by reducing the pressure and measuring the amount of the volatile components in the object from the weight difference before and after the evaporation. A volatile component amount measuring method, wherein an evaporation rate is calculated from a weight change curve therein, and a composition ratio of a plurality of components having different evaporation rates is simultaneously calculated based on the change point.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 2, the apparatus of the present invention comprises a decompression box, a balance, a vacuum pump, a data processing and control unit. The configuration will be described below with reference to FIG.

The decompression box is for lowering the atmospheric pressure of the sample to promote the volatilization of volatile components, and has an opening / closing mechanism for taking the sample in and out from the top or side. A transparent material is desirable from the viewpoint of monitoring the condition. A valve for suction and release by the control device is attached.

The balance is used to measure the initial weight of the sample, the weight during decompression, and the weight after decompression, and is set in a decompression box. As the balance, a normal electronic balance can be used as long as it has the required accuracy and pressure resistance.

The vacuum pump is for reducing the atmospheric pressure in the decompression box, and is selected from the ultimate degree of vacuum corresponding to the measurement accuracy and the evacuation speed corresponding to the measurement time. It is desirable that the pumping speed is constant, but usually an oil-rotation type is sufficient.

The purpose of the data processor is to calculate the weight reduction rate from the weight measurement data sent from the balance and to simultaneously execute the weight reduction at that time. The form is arbitrary as long as it has four arithmetic operations for calculating each data of the weight value and the final decompression weight value and a function of performing time differentiation of the decompression weight value.

The purpose of the control device is to send each instruction signal for starting the weight measurement, starting the operation of the vacuum pump, ending the measurement of the weight, closing the suction valve and opening the vacuum pump side, and ending the operation of the vacuum pump. It is. These processing / control devices can be functionally used even if they are built in the balance, but from the viewpoint of operability, it is desirable that they are outside the decompression box.

[0019]

An embodiment is shown below. A mixture having the following composition was prepared. Water 50% by weight 1-butanone 50% by weight The amount of each volatile component was measured by the following procedure. The operation was performed using signals from the controller to the balance, vacuum pump, and valve. Place the aluminum cup on the balance table Place about 0.6 ml of the sample in the aluminum cup placed on the balance table Quickly close the lid of the decompression box Send the measurement start instruction to the balance and instruct the weight measurement and time differentiation Instructs the start of operation of the vacuum pump. Ends the measurement when the change in the weight data from the balance becomes 0. Instructs to close the suction valve and opens the valve on the vacuum pump. Instructs to end the operation of the vacuum pump. Thus, the change point of the time derivative is obtained, and the weight loss at that time is calculated. As a result of calculating the total volatile content weight, the 1-butanone ratio was 47% by weight, and the water ratio was 53% by weight, which was an error of 3% by weight.

[0020]

According to the present invention, the amounts and total amounts of a plurality of volatile components in a sample can be simultaneously and simply measured. The amount and the weight ratio of volatile components in the object that change by heating can be measured.

[Brief description of the drawings]

FIG. 1: Weight curve under reduced pressure of an equal mixture of water / 1-butanone

FIG. 2 is a graph showing a conceptual diagram of the apparatus of the present invention.

Claims (2)

[Claims] An apparatus for measuring the amount of volatile components in an object based on a difference in weight before and after the evaporation of volatile components in the object by depressurization, and evaporating from a weight change curve during decompression. A volatile component amount measuring device comprising: a data processing device that calculates a speed and simultaneously calculates a composition ratio of a plurality of components having different evaporation rates based on a change point thereof. 2. A method for measuring the amount of volatile components in an object by evaporating volatile components in the object by decompression and measuring the amount of volatile components in the object from a difference in weight before and after the evaporation. A method for measuring the amount of volatile components, comprising calculating a speed and simultaneously calculating a composition ratio of a plurality of components having different evaporation rates based on a change point thereof.