KR101889166B1 - Decomposition method of a sample for icp analysis - Google Patents

Abstract

TECHNICAL FIELD The present invention relates to a method of decomposing a sample subjected to ICP analysis, and more particularly, to a method of decomposing a sample for analyzing heavy metals in a soil at a steel mill landfill.

Description

[0002] DECOMPOSITION METHOD OF A SAMPLE FOR ICP ANALYSIS [

TECHNICAL FIELD The present invention relates to a method of decomposing a sample subjected to ICP analysis, and more particularly, to a method of decomposing a sample for analyzing heavy metals in a soil at a steel mill landfill.

In general, the content of residual heavy metals in soil is measured by 1) pretreatment with pretreatment, and 2) by atomic absorption spectrophotometry, inductively coupled plasma-atomic emission molecular method.

More specifically, according to the soil pollution process test standard (Ministry of the Environment Notice No. 2009-180, August 25, 2009), after hydrolyzing the soil, the absorption liquid was collected with 0.5 mol of nitric acid, mm size, 100 mesh), and then 3 g is used as a sample.

The sample was placed in a reaction vessel for 2 hours and reacted, followed by thermal decomposition using a reflux condenser (FIG. 1) for about 2 hours. The filtrate is then transferred to a 100 ml volumetric flask and then measured with an inductively coupled plasma after the indicator.

As described above, when analyzing by the reflux condenser, only one sample is analyzed for about 5 to 6 hours in one device, and the analysis time is excessively required. In order to simultaneously analyze several samples, a large number of devices are required, This is a low problem.

In addition, if the instrument used in the analysis is contaminated, it is necessary to perform a separate cleaning process.

In order to analyze the components of soil such as soil, various methods have been used to prepare a test solution and analyze it by an ICP analysis method.

At this time, as a sample decomposition method, a sample decomposition method using a microwave sample decomposition apparatus is used. It is advantageous to use less harmful chemical substances to the human body and to prevent volatilization of ingredients to be analyzed during decomposition, And the decomposition time is short, which is advantageous in that the analysis time can be significantly shortened compared to the conventional method.

Accordingly, in the case of decomposition using a microwave sample decomposition apparatus, a technique for establishing a sample amount, a reagent, an amount of use, a reagent kind, a decomposition condition, and the like is required.

One aspect of the present invention is to provide a sample capable of shortening the decomposition time and quickly and accurately analyzing in the ICP analysis in decomposing a sample for analyzing heavy metals in a soil of a steelworks landfill using a microwave A method for decomposing a sample to be analyzed.

According to an aspect of the present invention, there is provided a method of analyzing a sample, comprising the steps of: a) charging an analytical sample solution containing a decomposition reagent to a sample to be analyzed 1 to 3 g of ICP (inductively coupled plasma) b) The analytical sample solution is decomposed in a microwave decomposition apparatus at a decomposition temperature of 180 to 230 ° C., a pressure of 270 to 310 psi, a power of 500 to 700 W, a decomposition time of 13 to 17 minutes, Decomposition step; c) adding a masking reagent to the cooled sample vessel; And d) decomposing the analytical sample solution added with the masking reagent in a microwave decomposition apparatus at a decomposition temperature of 140 to 190 DEG C, a pressure of 80 to 120 psi, a power of 500 to 700 W, and a decomposition time of 10 to 20 minutes And a second decomposition step of cooling to room temperature,

The decomposition reagent is composed of 5 to 9 ml of hydrochloric acid, 2 to 4 ml of nitric acid and 1 to 2 ml of hydrofluoric acid, and the masking reagent is 1.0 to 2.0 g of H ₃ BO ₃ . do.

According to the decomposition method of the present invention, since the decomposition can be completed within 1 to 2 hours as compared with the conventional decomposition method which requires about 5 to 6 hours, it is possible to produce analytical samples that can be analyzed accurately in ICP analysis It is possible.

In addition, decomposition is carried out in a pressurized state and a closed state by using microwaves, so that there is no loss of samples, reagents, etc., and also an effect of preventing volatilization and improving the production efficiency can be obtained.

1 is a view showing the reflux cooling apparatus of FIG. 1; FIG.
2 is a view showing a microwave sample decomposing apparatus.
Fig. 3 shows ICP analysis results of a sample decomposed using a reflux cooling method and ICP analysis results of a sample decomposed using a microwave sample decomposition method of the present invention in an embodiment of the present invention (the y-axis in the graph is mg / kg < / RTI > unit).
FIG. 4 is a graph showing the results of repeated experiments in Table 2 in an embodiment of the present invention at a sigma level.

In the microwave sample decomposition apparatus, when a dielectric is inserted between the electrodes per week and a direct current is applied to the electrodes to create an electric field between the electrodes, the dielectric molecules become electric dipoles having positive and negative charges. Here, if the polarity of the voltage is changed and the direction of the electric field is reversed, the direction of the electric dipole changes. Therefore, when an electric field (high frequency electric field) whose direction changes between the electrodes at a very high speed is applied, the molecules of the semiconducting semiconductor are also reversed at the same speed. At this time, the generated heat promotes the decomposition reaction of the acid and the solid sample, so that it can be decomposed into a small amount of acid. In addition, the microwave is an electromagnetic wave having a frequency of 300 to 300,000 MHz, and is composed of an electric field and a magnetic field. The energy of the photon constituting the electric field is 0.037 kcal / mol, and relative to the energy of 80-120 kcal / Low, producing energy that can heat the material by causing impulse between other molecules due to rotational motion of the molecule without cutting or deforming the molecular bond.

On the other hand, in the ICP analysis method, a sample solution is transferred to a high-temperature argon plasma flame by a carrier gas and passed through a torch center tube in an air jet state to measure the content of the sample atoms by the spectral intensity of each luminous element. In order to perform such ICP analysis, it is necessary to prepare a sample in a solid state in a uniform liquid state, and a technique for preparing a sample suitable for the rapidity and accuracy of analysis is an important key factor.

Accordingly, in the present invention, in producing a sample for measuring the heavy metal content of zinc, nickel, copper, lead, cadmium, arsenic and the like in soil in a landfill of a steelworks by ICP (inductively coupled plasma) And it is technically significant to provide an optimal decomposition method capable of producing a sample for ICP analysis that can be analyzed quickly and accurately.

Hereinafter, the present invention will be described in detail.

It is preferable that the decomposition method of the ICP analysis sample according to one aspect of the present invention is carried out by the following steps.

a) charging an analytical sample solution having a decomposition reagent added to a sample of 1 to 3 g of ICP (inductively coupled plasma) analysis into a sample vessel in a microwave decomposition apparatus;

b) The analytical sample solution is decomposed in a microwave decomposition apparatus at a decomposition temperature of 180 to 230 ° C., a pressure of 270 to 310 psi, a power of 500 to 700 W, a decomposition time of 13 to 17 minutes, Decomposition step;

c) adding a masking reagent to the cooled sample vessel; And

d) The analytical sample solution to which the masking reagent is added is decomposed again in a microwave decomposition apparatus at a decomposition temperature of 140 to 190 DEG C, a pressure of 80 to 120 psi, a power of 500 to 700 W and a decomposition time of 10 to 20 minutes Secondary decomposition step of cooling to room temperature.

More specifically, first, a sample to be analyzed, that is, a soil sample of a landfill in a steel mill is prepared and weighed 1 to 3 g, more preferably 1.5 to 2.0 g, of the soil sample. The sample is wetted with a small amount of water Reagents are added to prepare analytical sample solutions. Thereafter, it is preferable to load the sample solution for analysis in the sample vessel (sample decomposing cylinder 204) in the microwave sample decomposition apparatus shown in Fig.

The sample to be analyzed preferably contains at least one heavy metal selected from zinc (Zn), cadmium (Cd), arsenic (As), lead (Pb), copper (Cu) and nickel (Ni) In addition, it is preferable that the soil sample is selected by using a sample which has been sieved in a stepwise manner (for example, 0.15 mm size, 100 mesh).

The decomposition reagent preferably comprises 5 to 9 ml of hydrochloric acid, 2 to 4 ml of nitric acid, and 1 to 2 ml of hydrofluoric acid, and more preferably 6 to 8 ml and 2.5 to 3 ml of hydrochloric acid and nitric acid, respectively. It is preferable that the decomposition reagent prepared as above is added at a weight corresponding to 1.5 to 4.0 times the weight of the sample. If the weight of the decomposition reagent to be added is small (less than 1.5 times the weight of the sample), the sample may not be sufficiently decomposed. If the weight of the decomposition reagent is too large (more than 4.0 times the weight of the sample) There is a risk that the sample vessel may explode during the decomposition process.

It is preferable to cover the upper lid 203 of the sample container loaded with the analytical sample solution prepared as described above and then mount the lower protective frame 205 on the vessel heating plate 206.

Thereafter, it is preferable to decompose at a decomposition temperature of 180 to 230 deg. C, a pressure of 270 to 310 psi, a power of 500 to 700 W and a decomposition time of 13 to 17 minutes, and then cooled to room temperature. More preferably, it is advantageous to decompose at a decomposition temperature of 200 to 220 DEG C, a pressure of 280 to 300 psi, and a power of 550 to 650 W for 14 to 15 minutes.

After completion of the decomposition, it is preferable to add a masking reagent in the cooled sample container.

The masking reagent is preferably H ₃ BO ₃ , preferably 1.0 to 2.0 g. The use of H ₃ BO ₃ as the masking reagent is intended to prevent damage to inductively coupled plasma nozzles and the like caused by hydrofluoric acid (HF) in the decomposition reagent. HF remaining after decomposition is reacted with a glass ICP nozzle Therefore, it is preferable to add H ₃ BO ₃ in order to prevent this. Specifically, the H ₃ BO ₃ reacts with [4HF + H ₃ BO ₃ → HBF ₄ + 3H ₂ O], so that damage to the upper nozzle can be prevented.

The masking reagent of the present invention is preferably added at a weight corresponding to 1.6 to 3.5 times the weight of hydrofluoric acid (weight of reagent / weight of hydrofluoric acid) in the decomposition reagent. If the amount of the masking reagent is too small, the nozzle of the inductively coupled plasma may be damaged. If the amount of the masking reagent is too large, salt may be precipitated in the sample decomposition solution.

Thereafter, the sample container to which the masking reagent was added was mounted on a vessel heating plate in a microwave digestion apparatus, and then decomposed at a temperature of 140 to 190 ° C., a pressure of 80 to 120 psi, a power of 500 to 700 W, Min, and then cooled to 50 DEG C or lower, preferably to room temperature.

Deg.] C, more preferably a decomposition temperature of 160 to 180 [deg.] C, a pressure of 90 to 110 psi, and a power of 550 to 650 W for 14 to 15 minutes.

The reason for controlling the decomposition temperature and pressure to be lower than that in the first decomposition is to induce the reaction between the boric acid (H ₃ BO ₃ ) and the hydrofluoric acid (HF) while decomposing the undissolved product in the first decomposition .

From the completion of the cooling, a sample to be subjected to ICP analysis is prepared. Specifically, the ICP analysis target sample, specifically, the cooled decomposition solution, can be analyzed using inductively coupled plasma RF-POWER.

For example, ICP analysis can be performed at a power of 1200 W under the condition that the above digestion solution is charged in a polypropylene container, and the sample injection amount is set at 1.0 ml / min and the integration time is set at 40 seconds.

Hereinafter, the present invention will be described more specifically by way of examples. It should be noted, however, that the following examples are intended to illustrate the invention in more detail and not to limit the scope of the invention. The scope of the present invention is determined by the matters set forth in the claims and the matters reasonably inferred therefrom.

( Example )

1 ~ 3g of soil in a steel mill landfill containing heavy metals was prepared, and then an analysis sample solution was prepared by adding 6 ~ 8 ml of hydrochloric acid, 3 ml of nitric acid and 1 ml of hydrofluoric acid. Thereafter, the analytical sample solution was charged into a sample vessel, and then the sample vessel was attached to a microwave analysis apparatus and primary decomposition was performed. After 2 g of H ₃ BO ₃ was added to the sample vessel after the primary decomposition, the sample vessel was placed in the microwave analysis apparatus and subjected to secondary decomposition.

The primary decomposition was performed at a temperature of 210 DEG C, a pressure of 290 psi, and a power of 600 for 15 minutes. The secondary decomposition was conducted at a temperature of 170 DEG C, a pressure of 100 psi, and a power of 600 for 15 minutes.

After completion of the second decomposition, the decomposed liquid obtained is transferred into a 250 ml polypropylene container. ICP analysis was performed with inductively coupled plasma RF-POWER 1200W, sample injection amount 1.0 mL / min, integration time 40 seconds.

For comparison, an analytical sample was prepared by a conventional reflux cooling method, and ICP analysis was performed under the same conditions.

The measurement results of each metal (heavy metal) after the ICP analysis are shown in Table 1 and FIG.

Heavy metal type
Decomposition method Reflux cooling method Microwave decomposition method Zinc (Zn) 738 745 Cadmium (Cd) 1.512 1.506 Lead (Pb) 107 106 Nickel (Ni) 24.8 25.5 Arsenic (As) 32.6 33.3 Copper (Cu) 84.6 85.1

(The numerical unit in Table 1 is mg / kg).

Table 2 shows the results of ICP analysis after decomposition under the same conditions as above using the microwave sample decomposition method of the present invention.

Conduct No. Zinc (Zn) Cadmium (Cd) Copper (Cu) Lead (Pb) Nickel (Ni) Arsenic (As) One 785 1.55 89.2 112 25.7 33.8 2 752 1.49 88.7 107 25.9 35.1 3 739 1.53 81.6 102 26.8 32.6 4 772 1.54 83.5 109 27.2 33.8 5 726 1.61 87.9 101 23.5 32.7 6 735 1.52 89.5 104 25.8 35.1 7 718 1.46 82.6 116 24.5 31.9 8 754 1.50 81.8 102 26.8 32.4 9 739 1.39 83.7 105 24.8 32.8 10 728 1.47 82.9 107 23.9 32.8 Average 744.8 1.506 85.14 106.5 25.49 33.3 Standard Deviation 21.107 0.059 3.261 4.790 1.274 1.111 CV (%) 2.83 3.95 3.83 4.50 5.00 3.34

(In Table 2, the numerical unit is mg / kg).

As shown in Table 2 and FIG. 4, when the ICP analysis was repeated using the ICP analysis sample prepared by the microwave sample decomposition method of the present invention, the CV (Coefficient of Variation) Can be confirmed.

1 ... Reflux cooling system
20 ... Microwave sample decomposition device
200 ... screen window 201 ... input device
202 ... Tentable 203 ... Top cover
204 ... sample decomposing cylinder 205 ... protective frame
206 ... Vessel hot plate 207 ... vessel

Claims (4)

a) charging an analytical sample solution having a decomposition reagent added to a sample of 1 to 3 g of ICP (inductively coupled plasma) analysis into a sample vessel in a microwave decomposition apparatus;
b) The analytical sample solution is decomposed in a microwave decomposition apparatus at a decomposition temperature of 180 to 230 ° C., a pressure of 270 to 310 psi, a power of 500 to 700 W, a decomposition time of 13 to 17 minutes, Decomposition step;
c) adding a masking reagent to the cooled sample vessel; And
d) The analytical sample solution to which the masking reagent is added is decomposed again in a microwave decomposition apparatus at a decomposition temperature of 140 to 190 DEG C, a pressure of 80 to 120 psi, a power of 500 to 700 W and a decomposition time of 10 to 20 minutes And a second decomposition step of cooling to room temperature,
The decomposition reagent is composed of 5 to 9 ml of hydrochloric acid, 2 to 4 ml of nitric acid and 1 to 2 ml of hydrofluoric acid, the masking reagent is 1.0 to 2.0 g of H ₃ BO ₃ , and the masking reagent is 1.6 To 3.5 times (weight of reagent / weight of hydrofluoric acid).
The method according to claim 1,
Wherein the decomposition reagent is added at a rate of 1.5 to 4.0 times (weight of the reagent / sample weight) relative to the weight of the sample to be analyzed.
delete The method according to claim 1,
The ICP analysis sample in the step a) is a soil sample containing at least one heavy metal selected from zinc (Zn), cadmium (Cd), arsenic (As), lead (Pb), copper (Cu) and nickel Of the ICP target.

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