Atomic fluorescence analysis method and analysis device using water as carrier

Abstract

The present invention discloses an atomic fluorescence analysis method and device using water as a carrier, which belongs to the field of atomic fluorescence analysis in analytical chemistry. The method includes the steps of sampling and infusion, reaction of a test solution and a reducing agent in a reactor, atomization of the element to be tested and fluorescence detection, and in the conventional sampling and infusion process, water is used to replace HCl and a reducing agent as a carrier, so that the test solution and the reagent are pushed into the reactor by the water carrier to complete the reaction. The present invention uses water as a carrier, effectively overcomes the memory effect, improves the sensitivity and accuracy of the measurement, and saves a large amount of high-purity HCl and reducing agent NaBH4 at the same time, greatly reduces the analysis cost, and significantly improves the operating environment, which is an innovation of atomic fluorescence analysis technology.

Description

Technical Field

[0001] The invention belongs to the field of analytical chemistry and relates to atomic fluorescence analysis. It breaks through the traditional infusion mode and corresponding technology in the atomic fluorescence analysis method, and specifically relates to the improvement of the existing atomic fluorescence instrument and atomic fluorescence analysis method. Background Art

[0002] Atomic fluorescence analysis has been widely used in the determination of trace amounts of As, Sb, Bi, Hg, Se and other elements. The basic principle is that the ions of the element to be measured react with a strong reducing agent (usually potassium borohydride or sodium borohydride) in an acidic medium (usually hydrochloric acid) to be reduced to gaseous hydrides or atoms, while producing a large amount of hydrogen. The hydride molecules dissociate into ground state atoms in a high-temperature hydrogen flame and are excited to a high-energy state by the radiation of a specific frequency of the excitation light source. Since the high energy level is extremely unstable, the excited state atoms emit fluorescence of a characteristic wavelength in the form of light radiation during the de-excitation process. The fluorescence intensity is related to the concentration of the element to be measured, and the concentration of the element to be measured is obtained by measuring its fluorescence signal through a detector (usually a photomultiplier tube).

[0003] The atomic fluorescence analysis device (also called atomic fluorescence instrument, atomic fluorescence photometer) designed according to the above principle mainly includes an infusion system, a vapor generation system (or reactor), an atomizer, an excitation light source and a detection system. The test solution and the reducing agent are transmitted through the infusion system and carried by the carrier liquid (also called carrier fluid) into the reactor for chemical reaction, generating gaseous atoms or hydride molecules (collectively referred to as "vapor") and hydrogen, which enter the atomizer under the carrier gas (usually argon).

[0004] HCl and NaBH4 (or KBH4) have always been used as carriers for test solutions and reducing agents. This technology has the following defects: the infusion system has a serious memory effect. Especially after measuring high-concentration mercury samples, it is necessary to use blank solution to clean many times before measuring the next sample, which is time-consuming and even requires the entire infusion system to be replaced. The continuous use of a large amount of acid carrier liquid not only pollutes the operating environment, but also corrodes the instrument. At the same time, the carrier process consumes a large amount of high-purity HCl and relatively expensive reducing agents, which also increases the detection cost. Summary of the invention

[0005] The present invention aims to provide an atomic fluorescence analysis method and an analysis device using water as a carrier fluid, so as to effectively solve the above-mentioned problems in atomic fluorescence analysis.

[0006] The atomic fluorescence analysis method using water as a carrier current of the present invention comprises the steps of sampling and infusion, reaction of a test solution and a reducing agent in a reactor, atomization of the element to be tested and fluorescence detection, and is characterized in that in the conventional sampling and infusion process, water is used instead of HCl and a reducing agent as a carrier current, so that the test solution and the reducing agent are pushed into the reactor by the water carrier to complete the reaction.

[0007] Specifically, the sampling and infusion process is to firstly take samples, that is, to simultaneously introduce a test solution with a certain acidity and a reducing agent with a certain concentration, and then infuse, that is, to use pure water as a carrier to push the test solution and the reducing agent into the reactor.

[0008] The sampling time is 4-5 seconds, and the infusion time is 8-10 seconds.

[0009] In the above-mentioned atomic fluorescence analysis method using water as the carrier current, the acidity of the test solution is related to the element to be measured, and the concentration range of hydrochloric acid is 4%-10%. The concentration and acidity of the element solution commonly measured are shown in Table 1.

[0010] Table 1 Concentration and acidity of commonly measured element solutions

[0011] element As Sb Bi Se Hg Pb Cd Concentration / ng / ml 1-50 1-10 1-10 1-50 0.1-2 2-25 0.05-2 HCl / % 10 10 10 10 5-10 10 4

[0012] The present invention also provides an atomic fluorescence analysis device using water as a carrier current, comprising an infusion system, a reactor, an atomizer, an excitation light source and a detector, etc., and the characteristics are: the infusion system comprises: a test solution bottle for holding a test solution, the test solution bottle is connected to the reactor through a sample inlet tube; a reagent bottle for holding a reducing agent, the reagent bottle is connected to the reactor through a reagent inlet tube; a water bottle for holding pure water, the water outlet of the water bottle is connected to the sample inlet tube inlet and the reagent inlet tube inlet respectively through a water inlet tube, and the water inlet is controlled by switching the water inlet tube; and the infusion system does not contain a supporting device for infusing the carrier acid.

[0013] Based on the above device, the present invention further provides an atomic fluorescence analysis method using water as a carrier fluid, comprising the following steps:

[0014] Step 1: Prepare a series of standard solutions, sample solutions and NaBH4 solutions of different concentrations of the elements to be tested. Put the standard solutions and sample solutions into the test solution bottle, put the NaBH4 solution into the reagent bottle; and put the purified water into the water bottle.

[0015] Step 2: Make a standard curve:

[0016] 1) Connect the sample inlet tube to the test solution bottle interface containing the standard blank solution, connect the reagent inlet tube to the reagent bottle interface, and add liquid;

[0017] 2) Switch the sample inlet tube and the reagent inlet tube to connect with the water inlet tube, suck the carrier water into the sample inlet tube and the reagent inlet tube, and push the blank solution and the reducing agent with the carrier;

[0018] 3) The reactor, atomizer and excitation light source work, and the detector obtains a blank fluorescence value;

[0019] 4) Replace the test solution bottles containing standard solutions of different concentrations in order from low to high concentrations, repeat steps 1)-3), and sequentially measure and obtain the fluorescence value corresponding to each solution in the standard series;

[0020] 5) draw a fluorescence value-concentration standard curve;

[0021] Step 3, sample determination: After washing the injection tube with water, replace the test solution bottle containing the sample solution, repeat steps 1)-3) in step 2 to determine and obtain the fluorescence value corresponding to the sample solution, and obtain the concentration value of the element to be measured in the sample solution through the fluorescence value-concentration standard curve.

[0022] Wherein: the sampling and liquid inlet time in step 1) is 4-5 seconds; the time from the completion of switching the water inlet pipe in step 2) to the step 3) the detector obtaining the fluorescence value is 8-10 seconds.

[0023] Based on the above atomic fluorescence analysis device using water as a carrier current, the present invention further provides a simplified atomic fluorescence analysis device using water as a carrier current. In the simplified device, the sample inlet tube and the reagent inlet tube are both liquid inlet capillaries, and the water bottle is changed to two water cups, one water cup is used to hold cleaning water, and the other water cup is used to hold carrier water, and the ends of the two liquid inlet capillaries are interchangeably inserted in the two water cups.

[0024] Specifically, the liquid inlet capillary is connected to the reactor through a peristaltic pump, and the peristaltic pump controls the delivery speed and infusion volume of the test solution, reducing agent, cleaning water, and carrier water in the liquid inlet capillary.

[0025] Based on the simplified atomic fluorescence analysis device using water as a carrier current, the present invention provides a matching atomic fluorescence analysis method using water as a carrier current, comprising the following operations:

[0026] Procedure 1. Prepare the standard series solution and sample solution of the element to be tested, prepare the NaBH4 solution, and prepare two cups of pure water;

[0027] Operation 2. Start the atomic fluorescence analyzer and adjust it to the required working state;

[0028] Operation 3. Make a standard curve:

[0029] A1) Sampling: insert the two inlet capillary ends into the standard blank solution and NaBH4 solution respectively to take samples, and the peristaltic pump stops working after 4-5 seconds;

[0030] A2) Replacement: Take out the two capillary ends and place them in a cup of cleaning water to clean them, then transfer them to another cup of carrying water, and restart the peristaltic pump;

[0031] A3) Carrier water measurement: Carrier water carries standard blank solution and reducing agent into the reactor, and the instrument simultaneously measures the blank fluorescence signal and records the blank fluorescence value;

[0032] A4) After the blank fluorescence signal reaches stability, replace the blank solution with the standard solution, repeat the operations of A1) to A3) to measure the fluorescence signals of the standard series solutions in order from low to high concentrations and record the fluorescence values;

[0033] A5) Prepare fluorescence value-concentration standard curve;

[0034] Operation 4. Determine the sample: After cleaning the inlet capillary with cleaning water, measure the sample solution according to operations A1)-A3) to obtain the sample fluorescence value. From the fluorescence value-concentration standard curve, the concentration of the element to be measured in the sample solution is obtained. After inputting relevant parameters, the content of the element to be measured in the sample is calculated.

[0035] In the above operation 3, the sampling / delay / switch time / measurement time is 4-5 / 0 / 2-3 / 8-10 seconds respectively, that is, A1) sampling time is 4-5 seconds, delay is zero second, A2) swap time is 2-3, A3) current measurement time is 8-10 seconds.

[0036] By adopting the above scheme, the present invention creatively uses water as a carrier in the atomic fluorescence analysis process, ending the history of using HCl and NaBH4 as carriers for more than 30 years. Experiments have proved that the infusion technology using water instead of HCl and reducing agent as a carrier can not only detect trace or trace As, Sb, Bi, Pb, Se, Cd, Hg, etc. in the test solution, but also overcomes the technical prejudice that atomic fluorescence analysis cannot use water as a carrier in the general understanding. At the same time, unlike HCl and NaBH4 as carriers, ultrapure water does not contain the measured components, and will not react with the test solution or reducing agent in any chemical reaction during the infusion process, and there is no large amount of bubbles (caused by the generation of hydrogen by acid and reducing agent) adhering to the wall of the flow path, so that all infusion flow paths can be rinsed most thoroughly. Therefore, the atomic fluorescence instrument using water as a carrier effectively overcomes the memory effect, improves the sensitivity and accuracy of the measurement, and saves a large amount of high-purity HCl and reducing agent NaBH4, greatly reduces the analysis cost, and significantly improves the operating environment.

[0037] The present invention is described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the atomic fluorescence analysis device of the present invention using water as a carrier;

[0039] Figure 2 It is a simplified infusion system and infusion schematic diagram in the atomic fluorescence analysis using water as carrier fluid of the present invention;

[0040] Figure 3The peak curve (A, fluorescence value-time) and the 0.1-0.5 ng / mL standard curve (B, fluorescence value-concentration) of Cd were determined by the atomic fluorescence analysis method of the present invention using water as the carrier in Example 1;

[0041] Figure 4 For Example 2, the atomic fluorescence analysis method of the present invention using water as the carrier current was used to simultaneously determine the peak curve of Hg / As (A width, fluorescence value-time) and the standard curve of a mixed solution of 0.1-0.5 ng / ml Hg and 10-50 ng / ml As (B width, fluorescence value-concentration). DETAILED DESCRIPTION

[0042] The present invention discloses an atomic fluorescence analysis method and an analysis device using water as a carrier. A conventional atomic fluorescence analysis device includes an infusion system, a reactor, an atomizer, an excitation light source and a detector (see Figure 1 As shown), the test solution and the reducing agent (reagent) are introduced into the reactor by the infusion system, and hydrochloric acid and the reducing agent are used as carriers during the introduction process.

[0043] The design idea of ​​the present invention is to use water instead of HCl and reducing agent (reagent) as carrier flow in the conventional atomic fluorescence analysis infusion process. After the test solution and reducing agent are respectively input from the liquid aspiration capillary into their respective sample storage loops, both capillaries use pure water as carrier flow, and the test solution and reducing agent in each sample storage loop are pushed into the reactor for reaction under the carrier of water. At the same time, the pure water as carrier flow also cleans the pipeline of the infusion system.

[0044] According to the above design ideas, the composition of the atomic fluorescence analysis method device using water as the carrier current of the present invention is shown in Figure 1 As shown, the infusion system includes: a test solution bottle for holding a test solution, the test solution bottle is connected to the reactor through a sample inlet tube; a reagent bottle for holding a reducing agent, the reagent bottle is connected to the reactor through a reagent inlet tube; a water bottle for holding pure water, the water outlet of the water bottle is connected to the sample inlet tube inlet and the reagent inlet tube inlet respectively through a water inlet tube, and the water inlet is controlled by switching the water inlet tube. The unique design of the infusion system is that the infusion system does not include a supporting device for infusing hydrochloric acid, which is clearly distinguished and significantly different from the known infusion system. The infusion system, together with a conventional atomic fluorescence instrument including a reactor, an atomizer, an excitation light source and a detector, constitutes the atomic fluorescence analysis device of the present invention using water as the carrier current.

[0045] According to the above design ideas, in the atomic fluorescence analysis method of the present invention, a test solution of a certain acidity and a reducing agent of a certain concentration are first introduced simultaneously during the infusion process (influent), and then the test solution and the reducing agent are pushed (carrier push) into the reactor for reaction using pure water as a carrier, and the vapor after the reaction is atomized using an atomizer, and then the fluorescence signal of the element to be tested is obtained (determination) through an excitation light source and a detector to calculate the concentration of the element to be tested in the test solution. The infusion process does not use hydrochloric acid as a carrier, and the reducing agent carrier is also replaced by pure water, which is significantly different from the known infusion system and beyond conventional imagination.

[0046] The concentration ranges and acidity (HCl) of the main elements determined by the method of the present invention are shown in Table 1.

[0047] Table 1 Concentration and acidity of commonly measured element solutions

[0048] element As Sb Bi Se Hg Pb Cd Concentration / ng / ml 1-50 1-10 1-10 1-50 0.1-2 2-25 0.05-2 HCl / % 10 10 10 10 5-10 10 4

[0049] When the method of the present invention is used to determine the main elements, the concentration of the reducing agent NaBH4 (or KBH4) is shown in Table 2.

[0050] Table 2 Concentration of commonly used reducing agents

[0051] element As Sb Bi Hg As-Hg Pb Cd <![CDATA[NaBH4 / %]]> 1 1 1 0.2 1 2 2.5

[0052] Specific, combined Figure 1 As shown, the specific steps of the atomic fluorescence analysis method using water as the carrier flow can be:

[0053] Step 1: Prepare a series of standard solutions, sample solutions and NaBH4 solutions of different concentrations of the elements to be tested. Put the standard solutions and sample solutions into the test solution bottle, put the NaBH4 solution into the reagent bottle; and put the purified water into the water bottle.

[0054] Step 2, making a standard curve: 1) connect the sample injection tube to the test solution bottle interface containing standard blank solution (acid solution with a concentration of the element to be measured of 0), connect the reagent inlet tube to the reagent bottle interface, and inject liquid (4-5 seconds); 2) switch the sample injection tube and the reagent inlet tube to be connected to the water inlet tube, suck water into the sample injection tube and the reagent inlet tube, and push the blank solution and the reducing agent with the carrier (until the detection is completed in 8-10 seconds); 3) The reactor, atomizer, and excitation light source work, and the detector records the blank fluorescence value; 4) Replace the test solution bottles containing standard solutions of different concentrations in order from low to high concentration, repeat steps 1)-3), sequentially measure and obtain the fluorescence value corresponding to each solution in the standard series; 5) Draw a fluorescence value-concentration standard curve.

[0055] Step 3, sample determination: After washing the injection tube with water, replace the test solution bottle containing the sample solution, repeat steps 1)-3) to determine and obtain the fluorescence value corresponding to the sample solution, and convert the concentration value of the element to be measured in the sample solution through the fluorescence value-concentration standard curve.

[0056] The present invention uses water as the carrier of the atomic fluorescence analysis device, and the simplified infusion system is shown in Figure 2 As shown, it includes: a test solution bottle for holding a test solution and a reagent bottle for holding a reducing agent, the test solution bottle and the reagent bottle are connected to the reactor through a liquid inlet capillary; two water bottles for holding pure water, one (water cup 1) holds cleaning water for cleaning the capillary, and the other (water cup 2) holds carrier water as a carrier. A peristaltic pump can be used in the atomic fluorescence analysis infusion process. After the test solution and the reducing agent are respectively input into the sample storage loop (called "sampling") through two capillaries under the action of the peristaltic pump, the front section of the two capillaries near the head end is transferred to the cleaning pure water in the water cup 1 for cleaning (see Figure 2 Then the two capillary tips are transferred into the water cup 2 (see Figure 2 The midpoint line is called "insertion"), and the test solution and reducing agent in the sample loop are pushed into the reactor with pure water. Similarly, the atoms or molecular vapors produced by the chemical reaction are atomized after being input into the atomizer and excited by the radiation of the excitation light source. The emitted fluorescent signal is detected to obtain the concentration of the element to be measured in the test solution.

[0057] The time control in the atomic fluorescence analysis with water as the carrier current of the present invention is: sampling / delay / replacement (capillary) / determination: 4-5 / 0 / 2-3 / 8-10 (seconds). That is, the time for sucking the test solution and the reducing agent (i.e., sampling) is 4-5 seconds, the delay is usually zero seconds, the capillary is taken out of the test solution and the reducing agent, first placed in the water cup 1 for a while and then transferred to the water cup 2 (i.e., replacement) for generally 2-3 seconds. The time for the carrier water in the water cup 2 to push the test solution and the reducing agent in the sample loop until the determination is completed is 8-10 seconds, and the fluorescence signal of the element is measured during this period of time.

[0058] The specific operations of the detection instance are:

[0059] Operation 1. Prepare the standard series solution of the element to be tested, NaBH4 solution and related reagents as required. The sample solution must be prepared in advance. Place NaBH4 solution and two cups of pure water in the sample tray.

[0060] Operation 2. Turn on the power of the atomic fluorescence instrument, select single or dual channels on the desktop system settings page, confirm the test conditions, light up the light source of the element to be tested and preheat for 5-10 minutes. Open the valve of the Ar gas cylinder, adjust the Ar gas pressure to 0.3MPA, and open the exhaust device of the atomizer.

[0061] Operation 3. Make a standard curve:

[0062] 1) Sampling: insert the two inlet capillary ends into the standard blank solution and NaBH4 solution respectively, click "Blank" on the desktop standard page, the infusion system automatically executes the infusion program, and the peristaltic pump stops working after 4-5 seconds of sampling;

[0063] 2) Immediately take out the two capillaries and place them in the cleaning water of cup 1 to clean them, then transfer them to the pure water of cup 2 (the replacement time is 2-3 seconds), and restart the peristaltic pump;

[0064] 3) The carrier water in the water cup 2 carries the standard blank solution and the reducing agent into the reactor, and the instrument simultaneously measures the blank fluorescence signal and records the blank fluorescence value (the time from the carrier to the end of the measurement is 8-10 seconds);

[0065] 4) After the blank fluorescence signal reaches stability, the fluorescence signals of the standard series solutions are measured in order from low to high concentrations and the fluorescence values ​​are recorded; the peak curve of the fluorescence signal (fluorescence value-time) can be generated synchronously;

[0066] 5) Input the concentration of the standard solution into the desktop system, take the average value of each concentration of the standard solution, and create a fluorescence value-concentration standard curve.

[0067] Operation 4. Determine the sample: After cleaning the inlet capillary inserted into the test solution bottle with water, first measure the sample blank on the sample test page of the desktop system until it is stable, and then measure the fluorescence signal of each sample solution in sequence according to the test method of the standard solution in Operation 3. The concentration of the element to be measured in the sample solution is obtained from the fluorescence value of the sample from the fluorescence value-concentration standard curve. After entering the relevant parameters, the content of the element to be measured in the sample can be calculated.

[0068] The above method can determine a single element or two elements at the same time. When determining multiple elements, prepare standard mixed solutions of different elements with different concentrations, make standard curves of corresponding elements, and determine the content of the elements to be measured in each sample according to the above steps and operations. The present invention is further described below in conjunction with specific embodiments. The contents listed in the embodiments are examples rather than limitations of the present invention. The concentration "%" in the embodiments is expressed as mass percentage concentration.

[0069] Example 1: Analysis of Cd

[0070] Test samples: rice, soybeans

[0071] Preparation of cadmium standard curve: First prepare 10ng / ml cadmium standard solution (prepared now), then take 0, 0.5, 1.0, 1.5, 2.0, 2.5ml of this standard solution in 50ml plastic quantitative bottles, add 4ml of 50% HCl solution and 5ml of 5% thiourea to each solution, dilute to the scale with water, the concentration of this standard series solution is 0, 0.1, 0.2, 0.3, 0.4, 0.5ng / ml Cd. After shaking well, measure the fluorescence signal of blank and standard series solutions according to the operation process, and prepare the standard curve (see Figure 3 B, A is the peak curve of Cd).

[0072] Preparation and determination of test solution:

[0073] Weigh 0.1-0.2g of rice or soybean sample, place in a 50ml plastic quantitative bottle, add 4ml of 50% HCl and 5ml of 5% thiourea, shake for 5-10min, dilute to scale with water, shake well and use the sample solution as the test solution to measure the fluorescence signal of the sample solution according to the operation process, obtain the Cd concentration from the standard curve and convert it into the content in the sample. The determination results of Cd in food samples are shown in Table 3.

[0074] Table 3. Test results of Cd in rice and soybean powder (ng / g)

[0075]

[0076] From the data in the table, it can be seen that when the sample weight (G) varies greatly and the HCl concentration is 4%, the test sample is not pre-treated, and the use of water-based atomic fluorescence analysis can quickly determine the cadmium in rice and other foods. The measured Cd content in the sample is consistent with the recommended value.

[0077] In this determination operation, only pure water (18.2MΩ) is consumed without hydrochloric acid as a carrier, and the sampling time is reduced by about 50% compared with the conventional method. The NaBH4 solution is only needed to participate in the reaction, which saves more than 75% compared with conventional detection. The sample detection in Table 3 is measured from left to right. It can be seen that the concentration of cadmium in the solution can still be determined from high to low and the measurement results are accurate. It can be seen that using water as a carrier eliminates the memory effect. Even after the high-concentration standard solution is measured, the infusion system is cleaned by the carrier water, and the measurement of other concentration sample solutions is not affected.

[0078] Example 2: Simultaneous determination of Hg / As

[0079] Test sample: Soil

[0080] Since the content of As in soil is much higher than that of Hg, the existing atomic fluorescence spectrometer has not been able to simultaneously measure Hg and As in such samples. This embodiment uses water as a carrier to achieve simultaneous detection of Hg and As in the same sample.

[0081] Preparation of standard curve: Prepare a mixed standard solution containing 500ng / ml As and 5ng / ml Hg in advance. Take 0, 1, 2, 3, 4, 5ml of this standard solution in 50ml plastic quantitative bottles, add 5ml of 5% Vc-5% thiourea solution and 10ml of 50% HCl, dilute with water to the scale, and the Hg concentration in the obtained series of standard solutions is 0, 0.1, 0.2, 0.3, 0.4, 0.5ng / ml, and the As concentration is 0, 10, 20, 30, 40, 50ng / ml.

[0082] The double-channel method was selected, and the fluorescence signals of Hg and As in the blank and standard series solutions were simultaneously determined according to the above operation process, and standard curves of 0.1-0.5 ng / ml Hg and 10-50 ng / ml As of the mixed standard solution were prepared respectively. Figure 4 The A amplitude is the peak curve of Hg / As. Figure 4 Panel B is the standard curve of the mixed standard solution of Hg and As (the signal of the standard curve is calculated based on the spectrum area, and the blank area has been subtracted).

[0083] Preparation and determination of test solution: 0.1-0.2g soil sample is placed in a 50ml plastic quantitative bottle, 5ml of 5% Vc-5% thiourea solution is added, 10ml of HCl with a concentration of 50% is added, and diluted to the scale with water. After shaking, the sample solution is used as the test solution. According to the operation process, the fluorescence signals of Hg and As in the sample solution are simultaneously determined. The concentrations of the corresponding elements are obtained according to their respective standard curves, and the contents of each element in the sample are calculated. The determination results are shown in Table 4.

[0084] Table 4. Simultaneous determination results of soil Hg / As

[0085]

[0086] The data show that the method and device solve the difficulty of simultaneously determining Hg and As in soil. It can also be seen that the Hg concentrations in the six samples (standard samples) vary greatly. The results of the samples tested from top to bottom in Table 4 are consistent with the recommended values, indicating that the atomic fluorescence analysis method and device using water as the carrier current eliminates the serious memory effect in the determination of Hg.

[0087] In this embodiment, two elements coexist in the test solution, and the delivery system only needs to complete the test solution delivery once, and the detection of the dual-channel detection system is also completed once. In this measurement operation, water is used as the carrier fluid without the need for hydrochloric acid, and only 100ml-250ml of NaBH4 solution is needed to participate in the reaction, which greatly reduces the time and cost of the entire testing process.

Claims

1. A method for atomic fluorescence analysis using water as carrier fluid, comprising the steps of sampling and infusion, reaction of a test solution and a reducing agent in a reactor, atomization of the element to be tested and fluorescence detection, characterized in that: In the conventional sampling and infusion process, water is used instead of HCl and reducing agent as carrier fluid, and a peristaltic pump is used to push the test solution and reducing agent into the reactor to complete the reaction. The sampling and infusion process is to firstly take samples, that is, introduce a test solution with a certain acidity and a reducing agent with a certain concentration at the same time, and then infuse, that is, use pure water as a carrier to push the test solution and the reducing agent into the reactor.

2. The atomic fluorescence analysis method using water as carrier according to claim 1, characterized in that: The sampling time is 4-5 seconds and the infusion time is 8-10 seconds.

3. The atomic fluorescence analysis method using water as carrier according to claim 2, characterized in that: The acidity of the test solution is related to the element to be tested, wherein the acidity of the test solution is adjusted by hydrochloric acid, and the concentration range of the hydrochloric acid in the test solution is 4%-10%.

4. An atomic fluorescence analysis device using water as carrier fluid, comprising an infusion system, a reactor, an atomizer, an excitation light source and a detector, characterized in that: The infusion system comprises: A test solution bottle for containing the sample solution to be tested, the test solution bottle being connected to the reactor through a sample injection tube; A reagent bottle for containing a reducing agent, the reagent bottle being connected to the reactor through a reagent inlet pipe; A water bottle for holding pure water, the water outlet of the water bottle is connected to the sample tube inlet and the reagent tube inlet respectively through two water inlet pipes, and the water inlet is controlled by switching the water inlet pipes; and The infusion system does not contain a supporting device for infusing the carrier acid.

5. The atomic fluorescence analysis device using water as carrier fluid according to claim 4, characterized in that: The sample inlet tube and the reagent inlet tube are both liquid inlet capillaries. The water bottle is changed to two water cups, one water cup is used to hold cleaning water, and the other water cup is used to hold carrier water. The liquid inlet heads of the two liquid inlet capillaries can be replaced in the two water cups.

6. The atomic fluorescence analysis device using water as carrier fluid according to claim 5, characterized in that: The two liquid inlet capillaries are connected to the reactor through a peristaltic pump, and the peristaltic pump controls the conveying speed and infusion volume of the test solution, reducing agent, cleaning water and carrier water in the liquid inlet capillaries.

7. An atomic fluorescence analysis method using water as a carrier fluid, using the device of claim 4, comprising the following steps: Step 1, prepare a series of standard solutions, sample solutions and NaBH4 solutions of different concentrations of the elements to be tested, put the standard solutions and sample solutions into the test solution bottle, put the NaBH4 solution into the reagent bottle; put the purified water into the water bottle; Step 2: Make a standard curve: 1) Connect the sample inlet tube to the test solution bottle interface containing the standard blank solution, connect the reagent inlet tube to the reagent bottle interface, and add liquid; 2) Switch the sample inlet tube and the reagent inlet tube to connect with the water inlet tube, suck the carrier water into the sample inlet tube and the reagent inlet tube, and push the standard blank solution and NaBH4 solution into the reactor respectively; 3) The reactor, atomizer and excitation light source work, and the detector obtains a blank fluorescence value; 4) Replace the test solution bottles containing standard solutions of different concentrations in order from low to high concentrations, repeat steps 1)-3), and sequentially measure and obtain the fluorescence value corresponding to each solution in the standard series; 5) draw a fluorescence value-concentration standard curve; Step 3, sample determination: After washing the injection tube with water, replace the test solution bottle containing the sample solution, repeat steps 1)-3) in step 2 to determine and obtain the fluorescence value corresponding to the sample solution, and obtain the concentration value of the element to be measured in the sample solution through the fluorescence value-concentration standard curve.

8. The atomic fluorescence analysis method using water as carrier fluid according to claim 7, characterized in that: The time for sampling and liquid entry in step 1) is 4-5 seconds; the time from the inhalation of carrier water in step 2) to the acquisition of fluorescence value by the detector in step 3) is 8-10 seconds.

9. An atomic fluorescence analysis method using water as a carrier fluid, using the device of claim 5 or 6, comprising the following operations: Procedure 1. Prepare the standard series solution and sample solution of the element to be tested, prepare the NaBH4 solution, and prepare two cups of pure water; Operation 2. Start the atomic fluorescence analyzer and adjust it to the required working state; Operation 3. Make a standard curve: A1) Sampling: insert the two inlet capillary ends into the standard blank solution and NaBH4 solution respectively to take samples, and the peristaltic pump stops working after 4-5 seconds; A2) Replacement: Take out the two capillary tips and place them in a cup of cleaning water to clean them, then transfer them to another cup of carrier water, and restart the peristaltic pump; A3) Carrier water measurement: Carrier water carries standard blank solution and NaBH4 solution into the reactor, and the instrument simultaneously measures the blank fluorescence signal and records the blank fluorescence value; A4) After the blank fluorescence signal reaches stability, replace the blank solution with the standard solution, repeat the operations of A1)-A3) to measure the fluorescence signals of the standard series solutions in order from low to high concentrations and record the fluorescence values; A5) Prepare fluorescence value-concentration standard curve; Operation 4. Determine the sample: After cleaning the inlet capillary with cleaning water, measure the sample solution according to operations A1)-A3) to obtain the sample fluorescence value. From the fluorescence value-concentration standard curve, the concentration of the element to be measured in the sample solution is obtained. After inputting relevant parameters, the content of the element to be measured in the sample is calculated.

10. The atomic fluorescence analysis method using water as carrier fluid according to claim 9, characterized in that: The sampling / delay / switching / measurement times are 4-5 / 0 / 2-3 / 8-10 seconds respectively, that is, A1) sampling time is 4-5 seconds, delay is zero seconds, A2) switching time is 2-3, A3) current measurement time is 8-10 seconds.

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