JPH07229870A - Measurement of concentration of potassium in wheat flour - Google Patents

Abstract

PURPOSE:To measure the concn. of potassium in an extract of wheat flour in order of several ten mg/l without performing conventional complicated operation requiring skill. CONSTITUTION:Potassium in wheat flour is extracted with ethyl alcohol and the obtained extract is subjected to flow injection analysis using a device equipped with a reagent passage 1 through which an ion strength buffer soln. flops at a predetermined speed, a sample passage 2 through which a carrier liquid flows at a predetermined speed, a sample injector 4 provided to the sample passage 2, the confluent passage 5 of the reagent passage 1 and the sample passage 2 and a flow cell 7 provided to the confluent passage 5 equipped with a potassium ion electrode 8 having a detection terminal made of a liquid membrane and a comparison electrode 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the concentration of potassium contained in wheat flour by using the FIA method (flow injection analysis method).

[0002]

2. Description of the Related Art The determination of potassium concentration in wheat flour has been carried out as a measurement of nutritional components.

Conventionally, the potassium concentration of wheat flour has been measured by an atomic absorption method or the like, but complicated operations such as ashing and extraction with hydrochloric acid have been required, which requires skilled operations.

The present invention has been made in view of the above points, and does not require a complicated and skillful operation as in the prior art, and potassium of several tens of milligram per liter order in an extract from wheat flour. It is an object of the present invention to provide a potassium concentration measuring method capable of measuring an ion concentration accurately, easily and quickly.

In recent years, the FIA method (flow injection analysis method) has been frequently used in process analysis. The FIA method requires only a small amount of reagents and samples, is an energy-saving analysis method, and once the FIA system setting conditions are set, it is possible to perform analysis without individual differences, and suitable for routine analysis. It is an effective analytical tool for improving FI was also measured in the determination of potassium in wheat flour.
The use of Method A is considered to be an effective means for analyzing potassium, and its development is desired.

[0006]

In view of the above circumstances, the inventor of the present invention uses the above-described flow of the ionic strength buffer and the FIA method using the potassium ion electrode detector to determine the potassium concentration in the extract from wheat flour. As a result of studying its application to the measurement of the concentration, the extraction method using the ethyl alcohol extraction method different from the conventional hydrochloric acid extraction method and the FIA method can accurately measure the potassium ion concentration in the extract, and the operation is simple. Became.

The method for measuring potassium concentration according to the present invention comprises extracting a potassium component in wheat flour with ethyl alcohol, and extracting the extract into a reagent channel in which an ionic strength buffer solution flows at a predetermined speed and a sample in which a carrier liquid flows at a predetermined speed. A flow channel, a sample injector provided in the sample flow channel, a confluent flow channel of the reagent flow channel and the sample flow channel, and a potassium ion electrode and a comparison electrode having a liquid film detection end Flow injection analysis is performed using a flow injection device including a mounted flow cell.

Although the present invention does not directly measure the amount of potassium, the amount of potassium in the extract is directly related to the amount of potassium in wheat flour, and if ashed wheat flour is used, It can be measured.

In the present invention, the ionic strength buffer is not limited, but those containing potassium and acetic acid, for example, 10 mg / l potassium and 20% acetic acid buffer can be preferably used. As the carrier liquid, ion-exchanged water or the like can be preferably used.

As the potassium ion electrode, a liquid film type ion electrode in which a neutral carrier is solidified with PVC together with an organic solvent can be preferably used.

Further, a silver-silver chloride electrode or the like can be preferably used as the reference electrode.

For extraction with ethyl alcohol, 3 ml of ethyl alcohol can be preferably used for 1 g of flour. In addition, at the time of extraction, it is possible to perform extraction in a short time by using ultrasonic treatment together.

Although the present invention measures potassium ions, it is also possible to measure ions such as Ca, Mg and Na which can be measured using an ion electrode.

[0014]

In the method for measuring potassium concentration in wheat flour of the present invention, 10 mg / l potassium /
When the one containing 0.2007 mol acetic acid-lithium acetate was used, the base potential was stabilized by mixing it with the ionic strength buffer in the confluent channel, and depending on the potassium concentration in the sample when the sample was injected. It is possible to detect peak signals.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of an FIA method apparatus used in the method for measuring the concentration of potassium extracted from wheat flour of the present invention.

In the apparatus shown in FIG. 1, 1 is a reagent channel,
Reference numeral 2 is a sample flow channel, 3 is a pump interposed in the reagent flow channel 1 and the sample flow channel 2, and the ionic strength buffer solution and the carrier liquid are supplied to the reagent flow channel 1 and the sample flow channel 2 by the operation of the pump.
Each of them flows at a predetermined speed. Also,
Reference numeral 4 is a sample injector provided in the sample flow channel 2, 5 is a confluent flow channel of the reagent flow channel 1 and the sample flow channel 2, 6 is a mixing coil interposed in the confluent flow channel 5, and 7 is a confluent flow channel 5 2 is a flow cell for measuring potassium, which is provided on the downstream side of the mixing coil 6. The flow cell 7 has a cell body 7 to which a potassium ion electrode 8 having a liquid film detection end and a reference electrode 9 are attached.

FIG. 2 is a graph of a calibration curve showing the relationship between the potential of wheat flour used in the potassium concentration measuring method according to the ethyl alcohol extract and the potassium concentration in the extract.

In this method, 1 g of wheat flour was suspended in 3 ml of ethyl alcohol, and this was washed with 100 ml of ion-exchanged water.
The sample is adjusted by setting the value to 1 and used as a sample.

When the potassium concentration in the sample is measured by this measuring method, the pump 3 is operated to flow the ionic strength buffer solution in the reagent channel 1 and the carrier solution in the sample channel 2 at a predetermined speed. In this state, the sample injector 4 injects a predetermined amount of sample into the sample flow path 2. Then, the carrier liquid mixed with the sample and the ionic strength buffer enter the confluent channel 5 and are mixed through the mixing coil 6, and then the flow cell 7
Get in Then, the potassium concentration is measured in the flow cell 7.

[0021]

[Measurement Example] A measurement example of an experiment using the measurement method of the above-described embodiment will be shown. Here, the setting conditions of the FIA system, the ionic strength buffer, and the FIA system were as follows. [FIA System] The two-channel FIA system shown in FIG. 1 was constructed.

In this case, the pump 3 is a mini pulse pump manufactured by Gilson, the sample injector 4 is a 7125 type Rubin Distort manufactured by Rheodyne, and the potassium ion electrode 8 is a flow reference electrode 4401 manufactured by Electrochemical Instruments.
Mold and cell body 7 are FLC-12 manufactured by Electrochemical Instruments Co., Ltd.
A mold flow cell was used. As an ion meter and a recorder (neither shown), an IOL50 type ion meter manufactured by Electrochemical Instruments Co., Ltd. and a recorder 250F type manufactured by Sekonic were used, respectively.

As the ionic strength buffer solution (reagent solution),
10 mg / l potassium / 0.2 mol lithium acetate, 0.
A mixed solution of 007 mol acetic acid was used. This ionic strength buffer solution is 1 mg of 10000 mg / l potassium standard solution stock solution.
1, 20.4 g of lithium acetate dihydrate and 0.4 of glacial acetic acid
It was adjusted by dissolving ml in 800 ml of water and making it 1 l. The stock solution of 10000 mg / l potassium standard solution was prepared by drying potassium chloride at 105 ° C., cooling and weighing 1.907 g to 100 ml. [Setting Conditions of FIA System] The flow rates of the reagent solution and water were set to 1 ml / min, the sample injection amount was set to 20 μl, and the mixing coil length was set to 500 cm.

The measurement results were as follows. (1) Calibration curve Wheat flour was extracted with ethyl alcohol as a sample, and the concentration range in which the calibration curve for wheat flour analysis was established was examined by changing the sample injection amount and the concentration of the ionic strength buffer. As a result, in the case of a sample injection amount of 20 μl and a buffer solution concentration of 0.2007 mol acetic acid-lithium acetate buffer solution, as shown in FIG. 2, FIA signal (potential difference) and potassium were observed in the potassium concentration range of 5 to 30 mg / l. The relationship with the concentration is a straight line y = 0.3x
It became +0.8. (2) Reproducibility of FIA signal Potassium concentration is 10 mg / l, 15 mg / l, 20 m
When g / l and 25 mg / l are used, the parallel accuracy of the FIA signal when the measurement is repeated 5 times is shown by relative standard deviation,
0.72%, 1.76%, 1.18%, 1.3 respectively
It was 0%. Therefore, the measurement accuracy of this measurement method in this concentration range is considered to be 2% or less in relative standard deviation.

[0025]

As described above, according to the potassium concentration measuring method of the present invention, potassium in wheat flour is extracted with ethyl alcohol, and the extract is a reagent channel, a sample channel, a sample injector and a flow cell. Since the flow injection analysis is carried out using the device equipped with and, the potassium concentration of several tens of grams per liter order contained in the wheat flour extract can be measured accurately, easily, and automatically. .

[Brief description of drawings]

FIG. 1 is an FIA used in the potassium concentration measuring method of the present invention.
It is a figure which shows schematic structure of a method apparatus.

FIG. 2 is a graph of a calibration curve showing the relationship between the potential of a potassium ion electrode of an ethyl alcohol extract of wheat flour used in the potassium concentration measuring method of the present invention and the potassium concentration in the extract.

[Explanation of symbols]

 1 Reagent Channel 2 Sample Channel 3 Pump 4 Sample Injector 5 Combined Channel 6 Mixing Coil 7 Flow Cell 8 Potassium Ion Electrode 9 Reference Electrode

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kuniko Sakai 5-3-1 Tsurugaoka, Oi-cho, Iruma-gun, Saitama Nissei Flour Milling Co., Ltd. (72) Inventor Aki Sakai Kichijoji-Kitamachi, Musashino-shi, Tokyo 4-13-14 Electric Chemistry Instrument Co., Ltd. (72) Inventor Akihide Hemi Kichijoji Kitamachi, Musashino City, Tokyo 4-13-14 Electric Chemistry Instrument Co., Ltd. (72) Inventor Taiichi Asano Kichijoji, Musashino City, Tokyo 4-13-14 Kitamachi Electric Chemical Instruments Co., Ltd.

Claims (1)

[Claims] 1. Potassium in wheat flour is extracted with ethyl alcohol, and the extract is applied to a reagent channel in which an ionic strength buffer flows at a predetermined rate, a sample channel in which a carrier liquid flows at a predetermined rate, and a sample channel. A sample injector provided, a confluent channel of a reagent channel and a sample channel, and a flow cell provided with a potassium ion electrode and a reference electrode having a liquid film detection end and interposed in the confluent channel. A method for measuring potassium concentration, characterized by performing flow injection analysis using a flow injection device.