WO2014189123A1

WO2014189123A1 - Sample pre-treatment method for measuring the quantity of toxic elements in agricultural produce samples

Info

Publication number: WO2014189123A1
Application number: PCT/JP2014/063639
Authority: WO
Inventors: 俵田　啓; 勝雄中村
Original assignee: 関西電力株式会社; 株式会社住化分析センター
Priority date: 2013-05-24
Filing date: 2014-05-23
Publication date: 2014-11-27
Also published as: HK1221284A1; JPWO2014189123A1; CN105452841A; JP5666070B1

Abstract

　Provided is a method with which it is possible to simply, accurately, rapidly and at a high extraction rate carry out on-site the pre-treatment of samples when measuring the quantity of toxic elements in agricultural produce samples of cereals, beans or seeds.　This is a pre-treatment method for samples for measuring of the quantity of at least one element selected from a group consisting of cadmium, arsenic, zinc, manganese, copper, lead and chromium, in agricultural produce samples selected from cereals, beans and seeds, characterized by containing: (i) a step in which the sample is coarsely ground; (ii) a step in which water is added to the coarsely ground sample and heated, transforming the β starch contained in the sample into α starch; (iii) a step in which an enzyme is added to the sample, transforming the α starch in the sample into sugar; (iv) a step in which hydrochloric acid is added to the sample to extract the elements being measured in the sample; and (v) a step in which solids are removed from the extracted liquid. The rough grinding of the sample is preferably carried out when measuring the moisture content of the sample, and the heating of the roughly-ground sample is preferably carried out by microwave.

Description

Sample pretreatment method for measuring the amount of harmful elements in crop samples

The present invention relates to a sample pretreatment method for measuring on-site the amount of harmful elements such as cadmium in crop samples such as rice, soybeans, sesame, etc., and particularly reduces work time and labor compared to conventional methods. And a method for improving the extraction rate of the measurement element.

In recent years, the accumulation of environmental pollutants in various scenes associated with industry and daily life has become a problem due to the growing awareness of social environmental awareness such as environmental conservation and health effects. Among environmental pollutants, harmful elements such as cadmium have caused serious problems due to their toxicity, and it is extremely important to know the amount of harmful elements contained in crops.

The amount of harmful elements contained in agricultural products is generally measured using an analytical instrument such as an ICP emission spectrometer or an atomic absorption photometer. For example, in the analysis of harmful elements such as cadmium contained in agricultural products by the Ministry of Agriculture, Forestry and Fisheries, measurement using an ICP emission spectroscopic analyzer or an atomic absorption photometer is employed.

However, the measurement using these instruments required not only very expensive analytical instruments and specialized pretreatment, but also a long processing time and labor. In addition, the measurement cannot be performed near the site, and it is necessary to send the sample to a facility where an analytical instrument is installed and perform the measurement there.

On the other hand, Patent Document 1 has been proposed as a method capable of measuring the amount of cadmium in a crop near the site. This method can be measured in a shorter time than the above method, but when the sample is a grain, legume or seed, it is necessary to finely pulverize with a miller at the time of pretreatment. In this case, there are problems such as troublesome washing of the miller and frequent occurrence of failure of the miller due to the long time for fine grinding. In this method, cadmium is extracted by increasing the contact ratio with hydrochloric acid by finely pulverizing the sample. However, since the mobility of cadmium ions from the plant cell structure cannot be ensured sufficiently, the amount of cadmium extracted is significantly reduced. There was a problem that a small number of samples occurred.

JP 2010-133949 A

The present invention has been devised in view of the above-described problems of the prior art, and its purpose is to provide cadmium, arsenic, zinc, manganese, copper, lead, and cereals in grains, beans, and seed crop samples. Another object of the present invention is to provide a method capable of performing pretreatment of a sample when measuring the amount of chromium element simply and accurately in a short time with a high extraction rate.

In order to achieve the above object, the present inventor has intensively studied a pretreatment method capable of completely extracting a measurement element by a simple method without performing pulverization with a miller. The sample is coarsely crushed so that the crusher used in the measuring device can be used, β-starch is converted to α-starch by adding water to this and heating, and α-starch is converted to sugar by adding an enzyme. By filtering the unnecessary components by extracting the measurement elements with hydrochloric acid after making the filterable liquid state, the problem of fine pulverization by Mirther can be solved and a high extraction rate of the measurement elements from the sample can be achieved. As a result, the present invention has been completed.

That is, the present invention has the following configurations (1) to (7).
(1) Measure the amount of at least one element selected from the group consisting of cadmium, arsenic, zinc, manganese, copper, lead and chromium in a crop sample selected from grains, beans or seeds. A sample pretreatment method for
(I) a step of coarsely crushing the sample;
(Ii) adding water to the coarsely pulverized sample and heating to convert β starch contained in the sample into α starch;
(Iii) adding an enzyme to the sample to convert alpha starch in the sample into sugar;
(Iv) adding hydrochloric acid to the sample to extract the measurement element in the sample, and (v) removing the solid matter from the extracted liquid.
(2) The method according to (1), wherein the coarse pulverization of the sample is coarse pulverization performed at the time of measuring the moisture content of the sample.
(3) The method according to (1) or (2), wherein the coarsely pulverized sample is heated by microwaves.
(4) The method according to any one of (1) to (3), wherein amylase, protease and cellulase are used as the enzyme.
(5) The method according to any one of (1) to (4), wherein the sample is shaken after the enzyme is added to the sample and after the hydrochloric acid is added.
(6) The method according to any one of (1) to (5), wherein the grains are rice, wheat or buckwheat, the beans are soybeans or peanuts, and the seeds are sesame or rapeseed .
(7) A kit comprising a device and a reagent for performing the method according to any one of (1) to (6).

Since the pretreatment method of the present invention does not pulverize the sample in order to increase the contact ratio with hydrochloric acid, it is not necessary to use a pulverizer such as a miller. There is no burden of replacement costs. Since coarse pulverization is sufficient instead of fine pulverization, the coarse pulverized sample generally used for measuring the moisture content of agricultural products can be used as it is, and the sample weighing and pulverization can be omitted. Further, as a result of these, the overall measurement time is short and the measurement cost is low. Furthermore, due to water content in the plant cell structure and effective destruction of the plant cell structure that restrains the measurement element, the measurement element has high mobility, and extraction by chlorine complexation is sufficiently performed. Therefore, the measurement element is completely extracted from the sample, and the measurement accuracy is high.

FIG. 1 is a schematic diagram showing the procedure of the pretreatment method of the present invention used in the examples. FIG. 2 is a schematic diagram showing the procedure of the conventional method B used in the examples.

The present invention is a sample pretreatment method for measuring the amount of a specific harmful element of a specific crop sample, and basically (i) a coarse pulverization step, (ii) a water addition & heating step, ( It consists of iii) enzyme addition step, (iv) hydrochloric acid addition step, and (v) solid matter removal step.

The crop sample targeted by the method of the present invention is selected from grains, beans, or seeds, and these crops are protected by the cellulose layer on the surface, so that they are in the state at the time of harvest. Is characterized in that the treatment liquid such as hydrochloric acid does not reach the starch layer inside. Examples of grains include rice, wheat, and buckwheat, examples of beans include soybeans, red beans, and peanuts, and examples of seeds include sesame and rapeseed.
The element to be measured in the method of the present invention is at least one element selected from the group consisting of cadmium, arsenic, zinc, manganese, copper, lead, and chromium. Since these elements have a harmful effect on the human body, it is necessary to monitor the content in crops before distribution.

In the (i) coarse pulverization step of the present invention, a sample of a crop to be measured is coarsely pulverized. Here, coarse pulverization refers to pulverization in which individual crushed pieces of a sample can be visually confirmed, and it is sufficient if the sample is divided into at least two pieces. Fine pulverization is not required so that individual crushed pieces of the sample cannot be visually confirmed. This is because, if divided into at least two pieces, the starch layer inside the sample is exposed, and the processing solution reaches the starch layer. The method of coarse pulverization is not particularly limited, and examples thereof include a method of hitting with a mallet or hammer or crushing with a hard material. Alternatively, a coarsely pulverized sample can be used as it is when measuring the moisture content of a crop sample. Thereby, the trouble of rough crushing or weighing can be omitted. When the sample is roughly pulverized as in the method of the present invention, the pulverizer can be easily cleaned with an air gun, etc. in a short time compared to fine pulverization, and the number of treatments per hour when processing a large number of samples is reduced. Increase significantly. In addition, since the miller is not used for coarse pulverization, it is not necessary to consider the failure or replacement of the miller, which is a device having a relatively short service life.

In the (ii) water addition & heating step of the present invention, water is added to the coarsely pulverized sample and heated to convert β starch contained in the sample into α starch. Since the coarsely pulverized sample is β starch having low hydrophilicity as it is as a large pulverized piece, the measurement element cannot be extracted with hydrochloric acid. Therefore, in this process, water is added to the coarsely ground sample and heated to wipe the sample, thereby converting β starch into α starch and making it colloidal. As a result, the hydrophilicity of the sample is increased, and the measurement element can be sufficiently extracted with hydrochloric acid. The water to be added may be ordinary tap water, but it is preferable to use ion exchange water. The amount of water to be added may be equal to or greater than the sample weight. There is no upper limit to the amount of water, but if it is too much, the amount to be removed later increases. The heating method is not particularly limited, and the container in which water is added to the sample may be heated as it is. However, it is preferable because it is simple, efficient, and preferably heated by a microwave in a microwave oven or the like. In the case of heating with microwaves, for example, it is sufficient to perform the heating at about 500 W for about 30 seconds. When there is no heating equipment on site such as outdoors, it can be heated by heat of dissolution generated by adding calcium chloride or calcium carbonate.

In the (iii) enzyme addition step of the present invention, an enzyme is added to the sample to convert α starch in the sample into sugar. In the above-described (ii) water addition & heating step, the sample is in a colloidal (gel) form, and thus cannot be filtered later. Therefore, in this step, the starch in the sample is decomposed into sugar by addition of the enzyme to change it into a smooth liquid. It is preferable that the enzyme is basically added in a neutral range in order to exert its ability. Further, after the enzyme is added to the sample, it is preferable to shake the sample in order to sufficiently infiltrate the sample into the sample. The enzyme is not particularly limited as long as the above object can be achieved. For example, amylase, protease, and cellulase are used. Amylase has the effect of degrading starch into sugar, and protease and cellulase have the effect of degrading the surface layer bran when the sample is, for example, rice. The amount of the enzyme added is sufficient if it is converted to sugar, and generally only needs to be equal to or greater than the volume of the sample weight.

In the (iv) hydrochloric acid addition step of the present invention, hydrochloric acid is added to the sample to extract the measurement element in the sample. As hydrochloric acid, a hydrochloric acid solution having a concentration of preferably 0.002 to 2M, more preferably 0.05 to 0.5M may be used. The use ratio of the hydrochloric acid solution is generally 5 to 100% by volume of the sample, more preferably 10 to 50% by volume. If the amount used is too small, a sufficient chlorine complex cannot be formed, and if the amount used is too large, impurities in the sample increase. The hydrochloric acid solution may be added directly to the sample, or the sample may be immersed in the hydrochloric acid solution. In short, a method that allows hydrochloric acid to sufficiently permeate the sample may be employed. Regardless of which method is employed, it is preferable to vigorously shake the sample in order to sufficiently permeate the sample with hydrochloric acid. By this step, the measurement element moved from the sample forms a chlorine complex. In particular, since all the measurement elements constrained in the sample in the steps (i) to (iii) move so as to be able to react with chlorine, complex formation is possible for all the measurement elements.

In the (v) solid removal step of the present invention, solids such as protein, crude fat, and ash are removed from the extracted liquid by filtration or centrifugation. Filtration is, for example, no. The filter paper of No. 2 may be used, and the centrifugation may be performed with the normal setting of the centrifuge. This significantly improves the applicability of the amount of measurement element to the measuring device.

A sample prepared through the pretreatment method including the steps (i) to (v) of the present invention can measure the amount of the measurement element by any conventionally known method. As the measuring method, for example, an ICP method, a fluorescent X-ray method, an immunoassay method, a voltammetry method, an absorption method or the like is used. Specifically, atomic absorption analysis (AAS), inductively coupled plasma atomic emission spectrometry (ICP- AES), inductively coupled plasma mass spectrometry (ICP-MS) or the like is used.

Hereinafter, the effect of the sample pretreatment method of the present invention will be concretely demonstrated by Examples. In addition, description of an Example is given only for understanding of invention, and this invention is not limited at all by this.

Example 1
After roughly pulverizing 50 brown rice samples with a near-infrared moisture meter (Ketto Scientific Laboratory Co., Ltd., rice wheat moisture meter SP-1D3 type), according to the following extraction operation (the pretreatment method of the present invention), An extract was prepared.
Extraction operation:
(I) 1 g of brown rice sample coarsely pulverized with a moisture meter is put into a PP bottle (polypropylene bottle), and then 2.5 mL of ion-exchanged water is added (see (i) in FIG. 1).
(Ii) Put PP bottle in microwave oven without cap and heat for about 500W for 30 seconds, then add 2.5mL of enzyme solution (Mixed solution of amylase, protease and cellulase: 10% by weight concentration) Close the cap of the PP bottle and shake it up and down by hand for about 10 seconds (see (ii) in FIG. 1).
(Iii) Remove the cap of the PP bottle, add 5 mL of 0.2N hydrochloric acid solution, close the cap tightly, and shake it up and down by hand for about 1 minute (see (iii) in FIG. 1).
(Iv) No. for new PP bottle. 2 Set filter paper and filter the whole solution of (iii) (see (iv) in FIG. 1).

On the other hand, nitric acid was added to 50 specimens of the same brown rice and heated on a hot plate for about 24 hours, and an extraction solution was prepared according to an extraction operation (conventional method A) in which hydrogen peroxide was added to complete decomposition just before the decomposition. In addition, although the conventional method A can be said to have an extraction rate of the measurement element of 100%, it requires a long-time pretreatment and is not used in the field. This conventional method A is implemented as a comparative index of the extraction ratio of the measurement element of the pretreatment method of the present invention.

Next, for the extract prepared according to the pretreatment method of the present invention and the extract prepared according to the conventional method A, the amount of each element of cadmium, manganese, and zinc using ICP-OES (VISTA-MPX manufactured by SII) Using a device (atomic absorption photometer: AA-7000 manufactured by Shimadzu Corporation, hydride generator: HVG-1 manufactured by Shimadzu Corporation) with an atomic absorption photometer added with a hydride generator The amount of total arsenic was measured. Then, the amount of the measured element in the extract of the method of the present invention and the amount of the measured element of the extract of the conventional method A are compared, and the amount of the measured element obtained in the conventional method A is obtained by the pretreatment method of the present invention. The ratio (%) of the amount of the measured element obtained was evaluated as the recovery rate. The closer the value of the recovery rate is to 100%, the more the extract obtained by the pretreatment method of the present invention extracts the measurement element from the plant cell structure. Table 1 shows the amounts and recovery rates of each measurement element (cadmium, manganese, zinc, total arsenic) obtained by the conventional method A and the pretreatment method of the present invention for each brown rice specimen (sample numbers 1 to 50). Shown in

As is clear from the results in Table 1, the sample obtained by the pretreatment method of the present invention can be processed in a short time, but in the same manner as the conventional method A that requires a long time, cadmium, manganese, It is recognized that the measurement elements of zinc and arsenic are completely extracted.

Comparative Example 1
After pulverizing 50 brown rice samples one by one with a laboratory pulverizer (labor mill surplus LM-PLUS, manufactured by Osaka Chemical Co., Ltd.), an extract of conventional method B is prepared according to the following extraction procedure (conventional method B). did.
Extraction operation:
1 g of the finely ground brown rice sample is put into a PP bottle (polypropylene bottle), and 10 mL of 0.1N hydrochloric acid is subsequently added. The PP bottle was shaken vigorously up and down for about 1 minute by hand, 2 Put in a new PP bottle with filter paper and filter the whole volume (see Fig. 2).

On the other hand, an extract of the conventional method A was prepared from the same 50 brown rice samples in the same manner as in Example 1 according to the conventional method A described above.

Next, for the extract prepared according to the conventional method B and the extract prepared according to the conventional method A, the amount of each element of cadmium, manganese, and zinc was measured using ICP-OES (Vista-MPX manufactured by SII). Using a device in which a hydride generator is added to the atomic absorption photometer (atomic absorption photometer: AA-7000 manufactured by Shimadzu Corporation, hydride generator: HVG-1 manufactured by Shimadzu Corporation) The amount was measured. And the ratio (%) of the quantity of the measurement element obtained by the conventional method B with respect to the quantity of the measurement element obtained by the conventional method A was evaluated as a recovery rate. The closer the value of this recovery rate is to 100%, the more the extract obtained by the conventional method B indicates that the measurement element is completely extracted from the plant cell structure. Table 2 below shows the amounts and recovery rates of the measurement elements (cadmium, manganese, zinc, total arsenic) obtained by the conventional method A and the conventional method B for each brown rice specimen (sample numbers 1 to 50).

As is clear from the results in Table 2, in the conventional method B, sufficient extraction efficiency could not be obtained, so that there was a case where extraction was insufficient as in sample numbers 13 and 17 in Table 2. In the conventional method B, the extraction operation is simpler than in the conventional method A. However, in order to prevent a fine grinding time of about 2 minutes per specimen and a motor overheating of the grinding machine 5 Since each sample is finely pulverized, a cooling time of about 15 minutes is required. Therefore, the pulverization processing of 50 samples requires a total time of about 4 hours. On the other hand, in the pretreatment method of the present invention as shown in Example 1, it takes almost no time for the pulverization operation. Therefore, when 50 samples are processed, it takes 3 hours or more as compared with the conventional method B. The time could be shortened.

Example 2
After 20 soybean samples were beaten in an agate mortar and coarsely pulverized, an extract of the method of the present invention was prepared according to the pretreatment method of the present invention in the same manner as in Example 1.

On the other hand, an extract of conventional method A was prepared in the same manner as in Example 1 from 20 samples of the same soybean according to the conventional method A described above.

Next, for the extract prepared according to the pretreatment method of the present invention and the extract prepared according to the conventional method A, the amount of each element of cadmium, manganese, and zinc using ICP-OES (VISTA-MPX manufactured by SII) Using a device (atomic absorption photometer: AA-7000 manufactured by Shimadzu Corporation, hydride generator: HVG-1 manufactured by Shimadzu Corporation) with an atomic absorption photometer The amount of total arsenic was measured. Then, the amount of the measured element in the extract of the method of the present invention and the amount of the measured element of the extract of the conventional method A are compared, and the amount of the measured element obtained in the conventional method A is obtained by the pretreatment method of the present invention. The ratio (%) of the amount of the measured element obtained was evaluated as the recovery rate. The closer the value of the recovery rate is to 100%, the more the extract obtained by the pretreatment method of the present invention extracts the measurement element from the plant cell structure. Table 3 below shows the amounts and recovery rates of each measurement element (cadmium, manganese, zinc, total arsenic) obtained by the conventional method A and the pretreatment method of the present invention for each soybean sample (sample numbers 1 to 20). Shown in

As is clear from the results in Table 3, the sample obtained by the pretreatment method of the present invention can be processed in a short time, but in the same manner as in the conventional method A that requires a long time, cadmium, manganese, It is recognized that the measurement elements of zinc and arsenic are completely extracted.

Comparative Example 2
Twenty soybean samples are pulverized one by one with a laboratory pulverizer (labor mill surplus LM-PLUS, manufactured by Osaka Chemical Co., Ltd.), and then 10 samples are baked on a hot plate for 30 minutes until the color becomes dark. A sample was prepared (note: in the conventional method B soybean measurement, solid-liquid separation by filtration is not possible without baking treatment). From this sample, an extract of conventional method B was prepared according to the same extraction procedure as in conventional method B described in Comparative Example 1 (however, the shaking time was changed to 30 minutes).

On the other hand, an extract of conventional method A was prepared in the same manner as in Example 1 from 20 samples of the same soybean.

Next, for the extract prepared according to the conventional method B and the extract prepared according to the conventional method A, the amount of each element of cadmium, manganese, and zinc was measured using ICP-OES (Vista-MPX manufactured by SII). Using a device in which a hydride generator is added to the atomic absorption photometer (atomic absorption photometer: AA-7000 manufactured by Shimadzu Corporation, hydride generator: HVG-1 manufactured by Shimadzu Corporation) The amount was measured. And the ratio (%) of the quantity of the measurement element obtained by the conventional method B with respect to the quantity of the measurement element obtained by the conventional method A was evaluated as a recovery rate. The closer the value of this recovery rate is to 100%, the more the extract obtained by the conventional method B indicates that the measurement element is completely extracted from the plant cell structure. Table 4 below shows the amount of each measurement element (cadmium, manganese, zinc, total arsenic) obtained by the conventional method A and the conventional method B and the recovery rate for each soybean specimen (sample numbers 1 to 20).

As is clear from the results in Table 4, in the conventional method B, sufficient extraction efficiency could not be obtained, so that there was a case where extraction was insufficient as shown in Sample No. 11 in Table 4. Further, in the conventional method B, an additional baking process is required for the operation before the extraction, and the extraction time also requires about 30 minutes per sample. Therefore, the processing of 20 samples requires a total of 12 hours or more. Compared to the pretreatment method, a treatment time of 10 hours or more is required.

Example 3
After 20 sesame samples were beaten in an agate mortar and coarsely pulverized, the extract of the method of the present invention was prepared according to the pretreatment method of the present invention in the same manner as in Example 1.

On the other hand, from the same 20 samples of sesame, an extract of conventional method A was prepared in the same manner as in Example 1 according to conventional method A.

Next, for the extract prepared according to the pretreatment method of the present invention and the extract prepared according to the conventional method A, the amount of each element of cadmium, manganese, and zinc using ICP-OES (VISTA-MPX manufactured by SII) Using a device (atomic absorption photometer: AA-7000 manufactured by Shimadzu Corporation, hydride generator: HVG-1 manufactured by Shimadzu Corporation) with an atomic absorption photometer added with a hydride generator The amount of total arsenic was measured. Then, the amount of the measured element in the extract of the method of the present invention and the amount of the measured element of the extract of the conventional method A are compared, and the amount of the measured element obtained in the conventional method A is obtained by the pretreatment method of the present invention. The ratio (%) of the amount of the measured element obtained was evaluated as the recovery rate. The closer the value of the recovery rate is to 100%, the more the extract obtained by the pretreatment method of the present invention extracts the measurement element from the plant cell structure. Table 5 shows the amounts and recovery rates of the respective measurement elements (cadmium, manganese, zinc, total arsenic) obtained by the conventional method A and the pretreatment method of the present invention for each sesame sample (sample numbers 1 to 20). Shown in

As is clear from the results in Table 5, the sample obtained by the pretreatment method of the present invention can be treated in a short time, but in the same way as the conventional method A that requires a long time, cadmium, manganese, It is recognized that the measurement elements of zinc and arsenic are completely extracted.

Comparative Example 3
After pulverizing 20 sesame samples one by one with a laboratory pulverizer (labor mill surplus LM-PLUS, manufactured by Osaka Chemical Co., Ltd.), an extract of conventional method B was prepared according to conventional method B as in Comparative Example 1. did.

Next, for the extract prepared according to the conventional method B and the extract prepared according to the conventional method A, the amount of each element of cadmium, manganese, and zinc was measured using ICP-OES (Vista-MPX manufactured by SII). Using a device in which a hydride generator is added to the atomic absorption photometer (atomic absorption photometer: AA-7000 manufactured by Shimadzu Corporation, hydride generator: HVG-1 manufactured by Shimadzu Corporation) The amount was measured. And the ratio (%) of the quantity of the measurement element obtained by the conventional method B with respect to the quantity of the measurement element obtained by the conventional method A was evaluated as a recovery rate. The closer the value of this recovery rate is to 100%, the more the extract obtained by the conventional method B indicates that the measurement element is completely extracted from the plant cell structure. Table 6 below shows the amount of each measurement element (cadmium, manganese, zinc, total arsenic) obtained by the conventional method A and the conventional method B and the recovery rate for each sesame sample (sample numbers 1 to 20).

As is apparent from the results in Table 5, in the conventional method B, sufficient extraction efficiency could not be obtained, and thus extraction was sometimes insufficient as in sample numbers 5 and 13 in Table 6. Also, in the conventional method B, the extraction operation is simpler than in the conventional method A as in the case of the brown rice, but the fine grinding time for each sample is about 2 minutes per sample and the motor of the grinder is prevented from overheating. Therefore, a cooling time of about 15 minutes is required every time 5 specimens are finely pulverized, and therefore a total of about 2 hours is required for the pulverization process of 20 specimens. On the other hand, in the pretreatment method of the present invention as shown in Example 3, the pulverization operation takes almost no time, so that the operation can be performed in a time of ½ or less compared with the conventional method B. .

Comparative Example 4
Example of the extraction operation of the pretreatment method of the present invention of Example 1 using 10 brown rice samples except that the addition of water shown in (i) and the heating by the microwave oven shown in (ii) were not performed. In the same manner as in Example 1, an extract of Comparative Method A was prepared.

On the other hand, an extract of conventional method A was prepared in the same manner as in Example 1 from 10 samples of the same brown rice.

Next, for the extract prepared according to Comparative Method A and the extract prepared according to Conventional Method A, the amount of each element of cadmium, manganese, and zinc was measured using ICP-OES (Vista-MPX manufactured by SII). Using a device in which a hydride generator is added to the atomic absorption photometer (atomic absorption photometer: AA-7000 manufactured by Shimadzu Corporation, hydride generator: HVG-1 manufactured by Shimadzu Corporation) The amount was measured. And the ratio (%) of the quantity of the measurement element obtained by the comparative method A with respect to the quantity of the measurement element obtained by the conventional method A was evaluated as a recovery rate. The closer the value of this recovery rate is to 100%, the more the extract obtained by the comparative method A indicates that the measurement element is completely extracted from the plant cell structure. Table 7 below shows the amounts and recovery rates of the respective measurement elements (cadmium, manganese, zinc, total arsenic) obtained by the conventional method A and the comparative method A for each brown rice specimen (sample numbers 1 to 10).

As is clear from the results in Table 7, in Comparative Method A, the recovery rate is extremely reduced, and a sufficient extraction effect is not obtained.

Comparative Example 5
Extraction of Comparative Method B in the same manner as in Example 1 except that the enzyme shown in (ii) was not added in the extraction operation of the pretreatment method of the present invention in Example 1 using 10 brown rice samples. A liquid was created.

Next, for the extract prepared according to Comparative Method B and the extract prepared according to Conventional Method A, the amount of each element of cadmium, manganese, and zinc was measured using ICP-OES (Vista-MPX manufactured by SII). Using a device in which a hydride generator is added to the atomic absorption photometer (atomic absorption photometer: AA-7000 manufactured by Shimadzu Corporation, hydride generator: HVG-1 manufactured by Shimadzu Corporation) The amount was measured. And the ratio (%) of the quantity of the measurement element obtained by the comparative method B with respect to the quantity of the measurement element obtained by the conventional method A was evaluated as a recovery rate. The closer the value of the recovery rate is to 100%, the more the extract obtained by the comparative method B indicates that the measurement element is completely extracted from the plant cell structure. Table 8 below shows the amounts and recovery rates of the measurement elements (cadmium, manganese, zinc, total arsenic) obtained by the conventional method A and the comparative method B for each brown rice specimen (sample numbers 1 to 10).

As is clear from the results in Table 8, in the comparative method B, the recovery rate is extremely lowered and a sufficient extraction effect is not obtained.

Comparative Example 6
Using the 10 brown rice samples, an extract of Comparative Method C was prepared in the same manner as in Example 1 except that coarse pulverization was not performed using the moisture meter in the extraction operation of the pretreatment method of the present invention of Example 1. did.

Next, for the extract prepared according to Comparative Method C and the extract prepared according to Conventional Method A, the amount of each element of cadmium, manganese, and zinc was measured using ICP-OES (Vista-MPX manufactured by SII). Using a device in which a hydride generator is added to the atomic absorption photometer (atomic absorption photometer: AA-7000 manufactured by Shimadzu Corporation, hydride generator: HVG-1 manufactured by Shimadzu Corporation) The amount was measured. And the ratio (%) of the quantity of the measurement element obtained by the comparative method C with respect to the quantity of the measurement element obtained by the conventional method A was evaluated as a recovery rate. The closer the value of this recovery rate is to 100%, the more the extract obtained by the comparative method C indicates that the measurement element is completely extracted from the plant cell structure. Table 9 below shows the amount of each measurement element (cadmium, manganese, zinc, total arsenic) obtained by the conventional method A and the comparative method C and the recovery rate for each brown rice specimen (sample numbers 1 to 10).

As is clear from the results of Table 9, in Comparative Method C, the recovery rate is extremely reduced, and a sufficient extraction effect is not obtained.

Example 4
Of the extraction operation of the pretreatment method of the present invention of Example 1 using 10 brown rice samples, Example 1 except that the brown rice was divided into two with a mallet instead of performing coarse pulverization with a moisture meter. Similarly, an extract of the method of the present invention was prepared.

Next, for the extract prepared according to the pretreatment method of the present invention and the extract prepared according to the conventional method A, the amount of each element of cadmium, manganese, and zinc using ICP-OES (VISTA-MPX manufactured by SII) Using a device (atomic absorption photometer: AA-7000 manufactured by Shimadzu Corporation, hydride generator: HVG-1 manufactured by Shimadzu Corporation) with an atomic absorption photometer added with a hydride generator The amount of total arsenic was measured. Then, the amount of the measured element in the extract of the method of the present invention and the amount of the measured element of the extract of the conventional method A are compared, and the amount of the measured element obtained in the conventional method A is obtained by the pretreatment method of the present invention. The ratio (%) of the amount of the measured element obtained was evaluated as the recovery rate. The closer the value of the recovery rate is to 100%, the more the extract obtained by the pretreatment method of the present invention extracts the measurement element from the plant cell structure. Table 10 shows the amounts and recovery rates of the measurement elements (cadmium, manganese, zinc, total arsenic) obtained by the conventional method A and the pretreatment method of the present invention for each brown rice specimen (sample numbers 1 to 10). Shown in

As can be seen from Table 10, an acceptable level of recovery is achieved even with coarse pulverization with a mallet, and there are no examples showing extremely low values. It seems to be.

Example 5
In the extraction operation of the pretreatment method of the present invention in Example 1 using 10 brown rice samples, Example 1 except that brown rice was broken up to about 20 pieces with a mallet instead of performing coarse pulverization with a moisture meter. In the same manner, an extract of the present invention was prepared.

Next, for the extract prepared according to the pretreatment method of the present invention and the extract prepared according to the conventional method A, the amount of each element of cadmium, manganese, and zinc using ICP-OES (VISTA-MPX manufactured by SII) Using a device (atomic absorption photometer: AA-7000 manufactured by Shimadzu Corporation, hydride generator: HVG-1 manufactured by Shimadzu Corporation) with an atomic absorption photometer added with a hydride generator The amount of total arsenic was measured. Then, the amount of the measured element in the extract of the method of the present invention and the amount of the measured element of the extract of the conventional method A are compared, and the amount of the measured element obtained in the conventional method A is obtained by the pretreatment method of the present invention. The ratio (%) of the amount of the measured element obtained was evaluated as the recovery rate. The closer the value of the recovery rate is to 100%, the more the extract obtained by the pretreatment method of the present invention extracts the measurement element from the plant cell structure. Table 11 below shows the amounts and recovery rates of each measurement element (cadmium, manganese, zinc, total arsenic) obtained by the conventional method A and the pretreatment method of the present invention for each brown rice specimen (sample numbers 1 to 10). Shown in

As can be seen from Table 11, a sufficiently acceptable level of recovery was achieved even with coarse pulverization with a mallet, and no examples showing extremely low values were found. It seems to be practical.

Example 6
After roughly pulverizing 38 specimens of brown rice with a near-infrared moisture meter (Ketto Scientific Laboratory Co., Ltd., rice wheat moisture meter SP-1D3 type), in the same manner as in Example 1, according to the pretreatment method of the present invention, An extract was prepared.

On the other hand, an extract of the conventional method A was prepared in the same manner as in Example 1 from 38 samples of the same brown rice.

Next, with respect to the extract prepared according to the pretreatment method of the present invention and the extract prepared according to the conventional method A, cadmium, manganese, zinc, copper, lead using ICP-OES (Vista-MPX manufactured by SII) is used. , A device in which the amount of each element of total chromium was measured and a hydride generator was added to the atomic absorption photometer (atomic absorption photometer: AA-7000 manufactured by Shimadzu Corporation, hydride generator: manufactured by Shimadzu Corporation) The amount of total arsenic was measured using HVG-1). Then, the amount of the measured element in the extract of the method of the present invention and the amount of the measured element of the extract of the conventional method A are compared, and the amount of the measured element obtained in the conventional method A is obtained by the pretreatment method of the present invention. The ratio (%) of the amount of the measured element obtained was evaluated as the recovery rate. The closer the value of the recovery rate is to 100%, the more the extract obtained by the pretreatment method of the present invention extracts the measurement element from the plant cell structure. The amount of each measurement element (cadmium, manganese, zinc, copper, lead, total chromium, total arsenic) obtained by the conventional method A and the pretreatment method of the present invention for each brown rice specimen (sample numbers 1 to 38), and The recovery is shown in Table 12 below.

As is clear from the results in Table 12, the sample obtained by the pretreatment method of the present invention can be processed in a short time, but as in the conventional method A that requires a long time, cadmium, manganese, It can be seen that the measurement elements of zinc, copper, lead, chromium and arsenic are completely extracted.

The pretreatment method of the present invention is a simple and short time pretreatment of a sample for measuring the amount of cadmium, arsenic, zinc and / or manganese elements in a crop sample of grains, beans or seeds. Therefore, it is extremely useful as a pretreatment method performed near the site.

Claims

Sample for measuring the amount of at least one element selected from the group consisting of cadmium, arsenic, zinc, manganese, copper, lead and chromium in a crop sample selected from grains, beans or seeds The pre-processing method of
(I) a step of coarsely crushing the sample;
(Ii) adding water to the coarsely pulverized sample and heating to convert β starch contained in the sample into α starch;
(Iii) adding an enzyme to the sample to convert alpha starch in the sample into sugar;
(Iv) adding hydrochloric acid to the sample to extract the measurement element in the sample, and (v) removing the solid matter from the extracted liquid.
2. The method according to claim 1, wherein the coarse pulverization of the sample is coarse pulverization performed at the time of measuring the moisture content of the sample.
The method according to claim 1 or 2, wherein the coarsely pulverized sample is heated by microwaves.
The method according to any one of claims 1 to 3, wherein amylase, protease and cellulase are used as the enzyme.
5. The method according to claim 1, wherein the sample is shaken after the enzyme is added to the sample and after the hydrochloric acid is added.
The method according to any one of claims 1 to 5, wherein the grains are rice, wheat or buckwheat, the beans are soybeans or peanuts, and the seeds are sesame or rapeseed.
A kit comprising an instrument and a reagent for carrying out the method according to any one of claims 1 to 6.