CN103411931B - Based on the long-range LIBS quantitative elementary analysis method that weighting multiline is demarcated - Google Patents

Abstract

The invention discloses a kind of remote laser induced breakdown spectroscopy quantitative elementary analysis method of demarcating based on weighting multiline.First the method completes test site distant object LIBS spectra collection, in this process the essential element composition of the remote target to be measured of qualitative acquisition and line strength of element to be measured many spectral lines; Second step completes laboratory sample calibration, obtains the relation fit equation between element to be measured many line strength and degree; The last degree quantitatively calculating element to be measured according to multiline weighted method.The method can solve a long-range LIBS quantitative elementary analysis difficult problem preferably.

Description

Based on the long-range LIBS quantitative elementary analysis method that weighting multiline is demarcated

Technical field

This patent relates to a kind of laser spectrum quantitative elementary analysis method, particularly relates to a kind of remote laser induced breakdown spectroscopy (Laser-induced breakdown spectroscopy is called for short LIBS) quantitative analysis method of demarcating based on weighting multiline.

Background technology

In the occasion that some testers cannot be close, as chemical contamination region; The regions with a varied topography such as crag, river valley, solution cavity, carry out matter chemistry element composition and content analysis is a difficult problem, because tester cannot gather target sample carry out chemical analysis.In this case, remote laser induced breakdown spectroscopy (LIBS) Detection Techniques can be utilized to solve.

Remote laser induced breakdown spectroscopy (LIBS) Detection Techniques utilize high energy pulse laser, long-range target surface is focused on through condenser lens, focus point obtains the laser pulse of instantaneous high power density, the ablation of target surface focus point, evaporation and ionization can be made to form the plasma spark of high temperature, high pressure, high electron density, give off the spectrum comprising atom and ion characteristic spectral line, can be used for the element composition of detecting material.

A major issue of long-range LIBS detection technology is the content of how accurate analysis target component.Because tester cannot close to target, and the priori not having object element to form, make quantitative test become a difficult problem.

For solving long-range LIBS quantitative elementary analysis problem, this patent proposes a kind of long-range LIBS quantitative elementary analysis method of demarcating based on weighting multiline.First test site distant object LIBS spectra collection is completed, in this process the essential element composition of the remote target to be measured of qualitative acquisition and line strength of element to be measured many spectral lines; Second step completes laboratory sample calibration, obtains the relation fit equation between element to be measured many line strength and degree; The last degree quantitatively calculating element to be measured according to multiline weighted method.

Summary of the invention

The object of this patent is to provide a kind of long-range LIBS quantitative elementary analysis method of demarcating based on weighting multiline, solves long-range LIBS quantitative elementary analysis problem.

This patent is achieved like this, and its method step is:

Step one, complete test site distant object LIBS spectra collection

Set up long-range LIBS testing apparatus in test site, the domain test personnel between long-range LIBS testing apparatus and distant object are unapproachable (such as chemical contamination region, dangerous geographical environments such as precipice etc.).The LIBS spectroscopic data utilizing long-range LIBS testing apparatus to obtain distant object measures the distance L of distant object simultaneously with the laser range finder that testing apparatus is carried, in order to improve reliability and eliminate disturbance, the several times LIBS spectroscopic data that laser pulse induces is averaged, obtains the average LIBS spectroscopic data of distant object.According to the average LIBS curve of spectrum, obtain line strength that essential element forms and element X to be measured some spectral lines are corresponding of distant object.

Step 2, laboratory sample are demarcated

According to the essential element composition of the distant object that step one obtains, select the several compound containing element X to be measured and the main component of target, and by this several compound with several samples of different ratios row preparation, measure the quality of each compound in sample with balance, calculate the degree of element X in each sample according to molecular formula respectively.

In the lab, the mode the same with test site installs long-range LIBS testing apparatus, now tester can place sample on the position far away apart from long-range LIBS testing apparatus L, the repeatedly LIBS spectroscopic data of each sample collection is averaged, obtains line strength of some the spectral lines identical with step one of element X respectively.

Take line strength as ordinate, the degree of element X is horizontal ordinate, carries out linear fit, obtains the fitting a straight line equation of element X some spectral lines.

Step 3, multiline weighted method quantitatively calculate the degree K of element X to be measured.

The fitting a straight line equation of line strength that element X some the spectral lines obtained according to step one are corresponding and these spectral lines that step 2 obtains, can obtain the degree based on these spectral line gained of element X to be measured respectively.

These degree of confidence of degree based on the different spectral line gained of element X are directly proportional to the weight of line strength of these spectral lines, obtain the degree K of element X to be measured according to the weighted average calculation of these degrees.

The method in laboratory conditions, the calibration sample prepared is placed in the distance identical with on-the-spot test target, and many spectral lines that make use of element to be measured are demarcated, when finally calculating according to the spectral intensity of every bar spectral line as weight, utilize weighting multiline to demarcate the degree obtaining element to be measured, a difficult problem for long-range LIBS quantitative elementary analysis can be solved.

Accompanying drawing explanation

Fig. 1 is the schematic diagram of this patent, in figure: 1---solid pulse laser; 2---long-range LIBS electro-optical system; 3---fiber spectrometer; 4---laser range finder; 5---test site; 6---distant object; 7---sample A; 8---sample B; 9---sample C; 10---laboratory.

Embodiment

As shown in Figure 1, long-range LIBS testing apparatus comprises solid pulse laser 1, long-range LIBS electro-optical system 2, fiber spectrometer 3 and laser range finder 4 to the principle of this patent.

Step one, complete test site distant object LIBS spectra collection

Set up long-range LIBS testing apparatus in test site 5, the domain test personnel between long-range LIBS testing apparatus and distant object 6 are unapproachable (such as chemical contamination region, dangerous geographical environments such as precipice etc.).The laser pulse that solid pulse laser 1 sends focuses on through long-range LIBS electro-optical system 2 and excites distant object 6 induced synthesis LIBS spectral signal to receive through long-range LIBS electro-optical system 2 and be kept in fiber spectrometer 3.Measure the distance L of distant object 6 from long-range LIBS testing apparatus with the laser range finder 4 that proving installation carries simultaneously, in order to improve reliability and eliminate disturbance, 100 LIBS spectroscopic datas that laser pulse induces are averaged, obtain the average LIBS spectroscopic data of distant object 6.According to the average LIBS curve of spectrum, obtain the essential element composition of distant object 6 and element X spectral line I, line strength T that II, III are corresponding to be measured _i, T _iI, T _iII.

Step 2, laboratory sample are demarcated

According to the essential element composition of the distant object 6 that step one obtains, select three kinds of compounds containing element X to be measured and the main component of distant object 6, and by these three kinds of compounds with different than row preparation three sample A, B, C, measures the quality of each compound in sample, calculates A respectively according to molecular formula with balance, the degree K of element to be measured in B, C _a, K _b, K _c.

In laboratory 10, the mode the same with test site 5 installs long-range LIBS testing apparatus, and now tester can place sample A7 on the position far away apart from long-range LIBS testing apparatus L.100 LIBS spectroscopic datas that sample A7 gathers are averaged, obtain element X spectral line I, line strength T of II, III to be measured _iA, T _iIA, T _iIIA.

Similarly, use the same method, element X spectral line I, line strength T of II, III to be measured are obtained to sample B8 _iB, T _iIB, T _iIIB; Element X spectral line I, line strength T of II, III to be measured are obtained to sample C9 _iC, T _iIC, T _iIIC.

Take line strength as ordinate, the degree of element X to be measured is horizontal ordinate, according to coordinate points (K _a, T _iA), (K _b, T _iB), (K _c, T _iC) carry out linear fit, draw the fitting a straight line equation T (K) of element X spectral line I to be measured _i; By similar method, obtain the fitting a straight line equation T (K) of element X spectral line II to be measured _iIand the fitting a straight line equation T (K) of spectral line III _iII.

Step 3, multiline weighted method quantitatively calculate the degree K of element X to be measured.

According to the T that step one obtains _iand the fitting a straight line equation T (K) of spectral line I that step 2 obtains _i, the degree K based on spectral line I gained of element X to be measured can be obtained _i.Similarly, according to T _iIwith T (K) _iI, the degree K based on spectral line II gained of element X to be measured can be obtained _iI; According to T _iIIwith T (K) _iII, the degree K based on spectral line III gained of element X to be measured can be obtained _iII.

K _i, K _iI, K _iIIdegree of confidence and three line strength T _i, T _iI, T _iIIweight be directly proportional, quantitatively calculate the degree K of element X to be measured according to following formula:

$K=\frac{T_I}{T_I+T_{\mathrm{II}}+T_{\mathrm{III}}}{K}_I+\frac{T_{\mathrm{II}}}{T_I+T_{\mathrm{II}}+T_{\mathrm{III}}}{K}_{\mathrm{II}}+\frac{T_{\mathrm{III}}}{T_I+T_{\mathrm{II}}+T_{\mathrm{III}}}{K}_{\mathrm{III}}=\frac{T_I{K}_I+T_{\mathrm{II}}{K}_{\mathrm{II}}+T_{\mathrm{III}}{K}_{\mathrm{III}}}{T_I+T_{\mathrm{II}}+T_{\mathrm{III}}}.$

Claims (1)

1., based on the remote laser induced breakdown spectroscopy quantitative elementary analysis method that weighting multiline is demarcated, it is characterized in that comprising following three steps:

Step one, complete test site distant object LIBS spectra collection

Long-range LIBS testing apparatus is set up in test site (5), for chemical contamination region or the unapproachable region of dangerous geographical environment precipice tester between long-range LIBS testing apparatus and distant object (6), the laser pulse that solid pulse laser (1) sends excites distant object (6) induced synthesis LIBS spectral signal to receive through long-range LIBS electro-optical system (2) through the focusing of long-range LIBS electro-optical system (2) and is kept in fiber spectrometer (3); Measure the distance L of distant object (6) from long-range LIBS testing apparatus with the laser range finder (4) that long-range LIBS testing apparatus is carried simultaneously, in order to improve reliability and eliminate disturbance, 100 LIBS spectroscopic datas that laser pulse induces are averaged, obtain the average LIBS spectroscopic data of distant object (6); According to the average LIBS curve of spectrum, obtain the essential element composition of distant object (6) and element X spectral line I, line strength T that II, III are corresponding to be measured _i, T _iI, T _iII;

Step 2, laboratory sample are demarcated

According to the essential element composition of the distant object (6) that step one obtains, select three kinds of compounds containing element X to be measured and the main component of distant object (6), and by these three kinds of compounds with different than row preparation three sample A, B, C, measures the quality of each compound in sample, calculates A respectively according to molecular formula with balance, the degree K of element to be measured in B, C _a, K _b, K _c;

In laboratory (10), the mode the same with test site (5) installs long-range LIBS testing apparatus, and now tester places sample A (7) on the position far away apart from long-range LIBS testing apparatus L; 100 LIBS spectroscopic datas that sample A (7) gathers are averaged, obtain element X spectral line I, line strength T of II, III to be measured _iA, T _iIA, T _iIIA;

Similarly, use the same method, element X spectral line I, line strength T of II, III to be measured are obtained to sample B (8) _iB, T _iIB, T _iIIB; Element X spectral line I, line strength T of II, III to be measured are obtained to sample C (9) _iC, T _iIC, T _iIIC;

Take line strength as ordinate, the degree of element X to be measured is horizontal ordinate, according to coordinate points (K _a, T _iA), (K _b, T _iB), (K _c, T _iC) carry out linear fit, draw the fitting a straight line equation T (K) of element X spectral line I to be measured _i; By similar method, obtain the fitting a straight line equation T (K) of element X spectral line II to be measured _iIand the fitting a straight line equation T (K) of spectral line III _iII;

Step 3, multiline weighted method quantitatively calculate the degree K of element X to be measured

According to the T that step one obtains _iand the fitting a straight line equation T (K) of spectral line I that step 2 obtains _i, the degree K based on spectral line I gained of element X to be measured can be obtained _i; Similarly, according to T _iIwith T (K) _iI, the degree K based on spectral line II gained of element X to be measured can be obtained _iI; According to T _iIIwith T (K) _iII, the degree K based on spectral line III gained of element X to be measured can be obtained _iII;

K _i, K _iI, K _iIIdegree of confidence and three line strength T _i, T _iI, T _iIIweight be directly proportional, quantitatively calculate the degree K of element X to be measured according to following formula:

$K=\frac{T_I}{T_I+T_{\mathrm{II}}+T_{\mathrm{III}}}{K}_I+\frac{T_{\mathrm{II}}}{T_I+T_{\mathrm{II}}+T_{\mathrm{III}}}{K}_{\mathrm{II}}+\frac{T_{\mathrm{III}}}{T_I+T_{\mathrm{II}}+T_{\mathrm{III}}}{K}_{\mathrm{III}}=\frac{T_I{K}_I+T_{\mathrm{II}}{K}_{\mathrm{II}}+T_{\mathrm{III}}{K}_{\mathrm{III}}}{T_I+T_{\mathrm{II}}+T_{\mathrm{III}}}.$