Determination of Carbon Content in Steels Using Laser-Induced

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Determination of carbon content in steels using laser-induced breakdown spectroscopy assisted with laser-induced radical fluorescence Jiaming Li, Zhihao Zhu, Ran Zhou, Nan Zhao, Rongxing Yi, Xinyan Yang, Xiangyou Li, Lianbo Guo, Xiaoyan Zeng, and Yongfeng Lu Anal. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.analchem.7b01932 • Publication Date (Web): 01 Jul 2017 Downloaded from http://pubs.acs.org on July 4, 2017

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Analytical Chemistry

Determination of carbon content in steels using laser-induced breakdown spectroscopy assisted with laser-induced radical fluorescence Jiaming Li, Zhihao Zhu, Ran Zhou, Nan Zhao, Rongxing Yi, Xinyan Yang, Xiangyou Li*, Lianbo Guo, Xiaoyan Zeng, Yongfeng Lu Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology, Wuhan, Hubei 430074, P. R. China ABSTRACT: Carbon is a key element for steel properties, but hard to be determined by laser-induced breakdown spectroscopy (LIBS). Utilizing the combination of carbon in analytes and nitrogen in ambient gas to generate carbon-nitrogen (CN) radicals, LIBS assisted with laser-induced radical fluorescence (LIBS-LIRF) was proposed to resonantly excite radicals instead of atoms in plasmas. The CN radicals in the B2Σ-A2Π band were stimulated by a 421.60 nm laser wavelength, and emitted 388.34 nm fluorescence. The results show that the spectral intensity of the CN radicals was enhanced by two orders of magnitude using LIBS-LIRF. Then carbon content in steels was accurately and sensitively determined without spectral interference. The limits of detection (LoDs) were 0.039 and 0.013 wt.% in air and nitrogen gas, respectively. The limits of quantification (LoQs) were 0.130 and 0.043 wt.% in air and nitrogen gas, respectively. This work demonstrated the feasibility of LIBS to realize reliable carbon determination in steel industry.

Carbon element has always been a key element for steel properties. With low carbon contents, steels have high plasticity, ductility, tenacity, and thermal stability, suitable for weldments, rebars, pipelines, and hoisting cables. With high carbon contents, steels have high strength, hardness, and abrasive resistance, suitable for rails, tools, gear, and bearings. Therefore, it is crucial to determine carbon contents in steels for quality assurance. The conventional methods for carbon determination in steel include chemical titrimetry,1,2 spark source atomic emission spectrometry (SS-AES) in pure argon,3 particle-induced gamma-ray emission (PIGE)4,5 etc. These methods are so lengthy, complicated, short detective distance, timematerial consuming, or harmful for health, which makes them only be used in laboratories for offline analysis. In contrast, a rapid and online technique for carbon determination can not only evaluate product quality, but also provide real-time feedback in the steel manufacture.6 In past decades, researchers all around the world are making the efforts to develop new analytical methods to realize the goal. Laser-induced breakdown spectroscopy (LIBS) is an atomic spectrometry based on laser-ablation,7-9 in which elemental information is deduced by analyzing spectra emitted from laser-induced plasmas. With attractive advantages of in situ, remote detection, minimal sample preparation, rapid and multi-elemental detections, LIBS shows great potential in realtime analysis of steels, and has been tentatively applied in many fields, such as environmental protection,10 nuclear reaction monitoring,11 solar cells,12 special fibers,13 space exploration,14 archaeological verification,15 etc. In previous works about carbon determination by LIBS, some researchers chose C I 247.86 nm as an analytical line,16-19 but weak emission of carbon atoms and strong spectral interference from iron lines make it difficult to realize accurate and sensitive determination of carbon contents in steels.20 Some other researchers utilized

vacuum ultraviolet (VUV) lines to detect carbon in steels,21-29 but gas-tight tubes or chambers with noble gas and ultra-low pressure were necessary for optical probes to increase VUV transmittance, which makes it not feasible for industrial analysis in open air. In addition, carbon near-IR line was also used for steel analysis, but not sensitive enough for low-carbon steels.30 LIBS assisted with laser-induced fluorescence (LIBS-LIF) is a spectral enhancement method for LIBS signals. In LIBSLIF, target atoms were resonantly excited by a wavelengthtunable laser, whilst other atoms in plasma were almost unchanged. Therefore, the emission intensity of the target atoms is selectively enhanced. Detections of lead,31-33 cobalt,34,35 phosphorus,36,37 iron,32 boron,38 ytterbium,39 and thallium40 using LIBS-LIF were reported, which demonstrate high effectiveness in improving analytical sensitivity and accuracy. Because the addition is another laser beam compared with conventional LIBS, LIBS-LIF can keep most of the attractive advantages of LIBS, and is suitable for steel real-time analysis in the manufacture. However, all resonant lines of carbon atoms are in deep ultraviolet range under 170 nm, where the light is severely absorbed by air, and few commercial wavelength-tunable lasers are available in this range. Therefore, it is infeasible to resonantly excite carbon atoms to improve analytical accuracy and sensitivity. In this work, an alternative was proposed that carbonnitrogen (CN) radicals instead of carbon atoms in plasmas were resonantly excited. To be differentiated from conventional LIBS-LIF, this proposed approach was called LIBS assisted with laser-induced radical fluorescence (LIBS-LIRF). Though the CN radical emission was used to analyze organics (e.g. coal,41,42 bio-tissue,43 and polymers44) with high carbon contents, it is too weak to observe in steels with low carbon contents using conventional LIBS. In the proposed LIBS-LIRF,

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the CN radical emission was greatly enhanced by laser resonant excitation to detect carbon contents in steels.

EXPERIMENTAL SETUP AND SAMPLES Physical process of LIBS-LIRF. In our work, the CN radicals in the plasmas were used as the resonantly excited target. The physical process is shown in Figure 1 and described below. (a) Breakdown: the sample and ambient gas were simultaneously heated by the focused laser pulses, then produced plasmas. (b) Atomization: carbon in the sample and nitrogen in the ambient gas were atomized in the plasma. (c) Combination: carbon and nitrogen atoms combined to form CN radicals in the plasmas. (d) Excitation: the CN radicals were resonantly excited by the 421.60 nm laser, and then emitted 388.34 nm fluorescence.

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Shamrock 500i, grating of 1800 lines per mm) through a multicore fiber. Pure nitrogen (Wuhan Xiangyun Industry, 99.999% purity) gas was blown to cover the plasma for improving reaction efficiency between carbon and nitrogen atoms. An intensified charge-coupled device (ICCD) (Andor Technology, iStar 320T) was equipped to record the spectra. Both lasers and the ICCD were sequentially triggered by a digital delay generator (Stanford Research Systems, DG535). The OPO laser and the ICCD gate were simultaneously switched. The ICCD gate width was 10 ns. The interpulse delay was optimized to be 2 µs. The signals generated by 100 pulses of the ablation laser and enhanced by 100 pulses of the OPO laser were accumulated on the detector to generate one spectrum. Each sample was measured repeatedly for ten times.

Figure 2. Schematic diagram of the experimental setup.

Figure 1. Schematic diagram of LIBS-LIRF experimental process: breakdown (a), atomization (b), combination (c), and excitation (d)

Experimental Setup. A schematic diagram of the LIBS-LIF setup used in this work is shown in Figure 2. A Q-switched Nd:YAG laser (Beamtech Optronics, Nimma 400, pulse duration of 6 ns, flattened Gaussian beam) operating at 532 nm and 10 Hz was used as an ablation source. The laser beam was reflected by a mirror, and then focused onto sample surfaces to generate plasmas. To mitigate the laser damage to samples, the laser pulse energy and focal length for ablation were set at 2 mJ and 25 mm, respectively. The focal spot diameter on the sample is about 100 µm. The laser ablation fluence was 25.5 J/cm2. A wavelength-tunable laser, equipped with an optical parametric oscillator (OPO) (OPOTEK Inc., wavelength range of 410-710 nm) pumped by a Q-switched Nd:YAG laser (Quantel, Brilliant b, wavelength of 355 nm, repetition rate of 10 Hz), was used as an excitation source. The excitation laser beam was focused and covered the plasma by a UV-grade quartz lens (f = 150 mm). The pulse energy and irradiation density of the excitation laser at the plasma was about 15 mJ and 21.2 MW/cm2, respectively. The fluorescent light emission from the plasma was collected by a light collector (Ocean Optics, 84-UV-25, wavelength range: 200-2000 nm) and coupled into a Czerny-Turner spectrometer (Andor Technology,

Samples. Eight low-alloy steel samples from National Institute of Standards and Technology (1264a, 1270, 1761a, 1762a, 1763a, 1764a, 1766, and C1285, carbon contents: 0.015-1.05 wt.% listed in Table 1) were used to build a quantitative model in our work. One pig iron sample from Ansteel Research Institute (GSB03-2582-2010-7, carbon content: 4.13 wt.%), and one polyvinyl chloride (PVC) pellet ([CH2-CH-Cl]n carbon content: 38.4 wt.%) were used to observe CN radical spectra. Table 1. Carbon contents (wt.%) in low-alloy steels

NIST

Content

NIST

Content

1264a 1270 1761a 1762a

0.871 0.077 1.050 0.341

1763a 1764a 1766 C1285

0.202 0.592 0.015 0.058

RESULTS AND DISCUSSION The resonant photons can excite CN radicals in only one specific state. Because the X2Σ+ electronic state is the ground state in CN radicals45, the largest number of radicals were in the X2Σ+. Therefore, the CN radicals in the X2Σ+ state were chosen as the targets in the plasmas. Different from those in the atoms, electronic states in radicals were consisted of several vibrational and rotational levels. In this work, heads in vibrational bands were used, therefore rotational levels were not discussed.


Violet system B2Σ+-X2Σ+ is easily excited and of frequent occurrence in CN spectra.46 Transitions of (0, 0) 388.34 nm and (0, 1) 421.60 nm have the strongest emission in the violet system. The wavelength-tunable laser beam in our experiment was obtained from the OPO pumped by 355 nm laser (third harmonic of an Nd:YAG laser). The wavelength range of output from the OPO is 410-710 nm, where the B2Σ+-X2Σ+ (0, 1) 421.60 nm is in that range. However, a 388.34 nm laser beam requires mixing another 1064 nm and a 611.54 nm laser beams. Not only the pulse energy and stability will be greatly decreased, but also the cost will be raised. Moreover, the mixing model is sensitive to the ambient temperature, which makes it not suitable for application in industry. Therefore, (0, 1) 421.60 nm transition in the B2Σ+-X2Σ+ system was chosen as excitation in our work, while (0,0) 388.34 nm was the observation line.

The synchronicity between OPO light and CN fluorescence was studied, shown in Figure 5. In conventional LIBSLIF with atomic excitation, the laser-induced fluorescence is synchronic.34,47 In LIBS-LIRF, the OPO light and CN fluorescence rose and reached the peak synchronically. Then the fluorescence decayed 1-2 ns slower than OPO light. The result indicated the lifetime of the level B2Σ+ (ν=0) is about 1-2 ns. The whole lifetime of the CN fluorescent in this work is about 10 ns. Therefore, the gate width of the detector was set to be 10 ns in LIBS-LIRF signal acquisition.

OPO laser light Fluorescence

1.2 0.9 0.6 0.3 0.0 0

2

4

6

8

10

12

14

Time (ns)

Figure 5. Synchronicity between OPO laser and CN fluorescence of B2Σ+-X2Σ+ (0,0) in LIBS-LIRF.

Figure 6 shows the spectra of the pig iron sample in air and nitrogen by LIBS and LIBS-LIRF. No CN B2Σ+-X2Σ+ (0,0) 388.34 nm signal was observed in LIBS. However, strong signals without spectral interference were observed in LIBSLIRF with 421.60 nm laser excitation. Moreover, the spectral intensity of CN radicals in nitrogen gas was significantly greater than that in air, because nitrogen gas provided more sufficient nitrogen source for carbon-nitrogen generation than air, and it can prevent carbon from oxidization by oxygen atoms in air. In addition, there was a line of iron atoms in 421.62 nm, close to CN excitation line 421.60 nm. Therefore, the iron lines with the same upper level configuration as Fe I 421.62 nm were also enhanced in Figure 6.

20

5

4

Fe I 388.63 nm

Fe I 387.86 nm

8

OPO idler light

Rotational spectra

Fe I 387.25 nm

10

12

CN B2Σ+-X2Σ+ (1,1)

15

16 Fe I 385.99 nm

Head

LIBS in air CN B2Σ+-X2Σ+ (0,0) LIBS in nitrogen LIBS-LIRF in air LIBS-LIRF in nitrogen Fe I 385.64 nm

20

LIBS LIBS-LIRF CN B2Σ+-X2Σ+ (0,0)

Intensity (x104 counts)

25

Fe I 386.55 nm

Figure. 3. Schematic diagram of LIRF in CN radicals In the excitation process shown in Figure 3, the CN radicals in X2Σ+ (ν=1) were stimulated. When the photon energy of the OPO laser (421.60 nm) is equal to the energy gap (2.94 eV) between X2Σ+ (ν=1) and B2Σ+ (ν=0), the CN radicals in X2Σ+ (ν=1) transited up to B2Σ+ (ν=0). The CN radicals in B2Σ+ (ν=0) were not stable, then transited down to X2Σ+ (ν=0) and emitted 388.34 nm fluorescence. To prove the effectiveness of LIBS-LIRF, the CN radical spectra of the PVC sample acquired by LIBS and LIBS-LIRF were shown in Figure 4. The head intensity of B2Σ+-X2Σ+ (0, 0) 388.3 nm in LIBS-LIRF was much greater than that in LIBS under the same experimental condition. This proved that the CN radicals were significantly stimulated by the 421.60 nm laser, and their emission in 388.34 nm can be effectively enhanced.


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Normalized intensity

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0

0 382

384

386

388

Wavelength (nm) 2 +

2 +

Figure 4. B Σ -X Σ (0,0) spectra of the PVC sample using LIBS (black line) and LIBS-LIRF (blue line).

385.7 386.4 387.1 387.8 388.5 389.2 Wavelength (nm)

Figure 6. CN B2Σ+-X2Σ+ (0,0) 388.34 nm signals acquired by LIBS in air (black line), LIBS in nitrogen (green line), LIBSLIRF in air (blue line), and LIBS-LIRF in nitrogen (red line).



30 25

12

20

9

15

6

10

3

5

0

0 0

2

4

6

8

10

Interpulse delay (µ µs)

Figure 7. Influences of the interpulse delays on CN B2Σ+-X2Σ+ (0,0) fluorescence intensity acquired by LIBS-LIRF in air (blue scatters and line) and nitrogen (red scatters and line); and the ratio (green scatters and line) between fluorescence intensity in nitrogen and air.

0.60

2.6 0.55

2.4 2.2

0.50

2.0

0.45

1.8 0.0

0.2

0.4

0.6

0.8

1.0

1.2

Carbon content (wt.%)

0.6

(b)

CN 388.3 nm in nitrogen CN 388.3 nm in air

0.5 0.4 0.3 0.2 0.1

After investigations on the mechanism and behavior of laser-induced CN radical fluorescence in plasmas, the carbon contents in steels were determined. The internal calibration curves were established by LIBS and LIBS-LIRF, as shown in Figure 8. To reduce spectral fluctuation, C I 193.1 nm, C I 247.9 nm, and CN 388.34 nm were normalized by Fe II 188.87 nm, Fe I 248.3 nm, and Fe I 388.7 nm, respectively. The analytical performances were listed in Table 2. The limit of detections (LoDs) and limit of qualification (LoQs), which were calculated according to the 3σ/s and 10σ/s criteria, were used to evaluate sensitivity. Determination coefficient R2 represents analytical linearity. Accuracy was evaluated by calculating the root mean square error of cross-validation (RMSECV) in leave-one-out cross-validation (LOOCV) method. In atomic LIBS analyses, C I 193.1 nm line had an unreliable calculated LoD of 0.060 wt.% and LoQ of 0.200 wt.% due to the poor accuracy with an R2 factor of 0.871, and C I 247.9 nm intensity had no relation with the carbon content. Nevertheless, in LIBS-LIRF analyses, the R2 factors were greatly improved to 0.991 and 0.974 in nitrogen gas and air, respectively. It was demonstrated that LIBS-LIRF has a significantly higher analytical linearity than atomic LIBS. The LoDs were 0.013 wt.% in nitrogen gas and 0.039 wt.% in air. And

(a)

C I 193.1 nm C I 247.9 nm

2.8

Normalized intensity (C I 247.9 nm)

15

35

Ratio (Initrogen/Iair)

In air In nitrogen Ratio (Initrogen/Iair)

18

3.0

Normalized intensity (C I 193.1 nm)

21

LoQ were 0.043 wt.% in nitrogen gas and 0.130 wt.% in air. The RMSECV values were 0.046 and 0.078 wt.% in nitrogen gas and air, respectively, much better the 0.226 wt.% in LIBS. The results proved that LIBS-LIRF has a significantly higher sensitivity and accuracy than atomic LIBS for carbon content determination in steels. Furthermore, the excitation and observation windows for CN radical fluorescence are both in the visible range, where transmittance and efficiency of optical systems are satisfactory, and tubes or chambers with noble gas and ultra-low pressure are not necessary. That makes it suitable for online analyses of steels.

Normalized Intensity

Influences of the interpulse delays between the two lasers on CN B2Σ+-X2Σ+ (0,0) fluorescence intensity were investigated and shown in Figure 7. In the early stage (1 µs), the plasmas were just generated and the CN radicals started to form. The number of CN radicals in the plasmas was not large. Then the emission intensities reached the peaks at the interpulse delay of 2 µs, where the numbers of CN radicals maximized. With plasmas expanding and CN radicals combining with other particles in late stage, the intensities of CN fluorescence decayed. To acquire better fluorescence signals, the interpulse delay was optimized to be 2 µs in the determination of carbon content in steels. Moreover, comparing the intensities of CN fluorescence in air and nitrogen, the ratio between the fluorescence intensity in nitrogen kept increasing before 8 µs, which indicated the CN radicals decayed more slowly in nitrogen gas. Therefore, the nitrogen gas provided a more stable condition for CN radicals.


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0.0

0.2

0.4

0.6

0.8

1.0

1.2

Carbon content (wt.%)

Figure 8. (a) Internal calibration curves of carbon in steels measured by LIBS with atomic lines 193.1 nm (purple scatters and line) and 247.9 nm (orange scatters and line); (b) internal calibration curves of carbon in steels measured by LIBS-LIRF in nitrogen gas (red scatters and line) and air (blue scatters and line). Table 2. Carbon contents (wt.%) in low-alloy steels

LIBS LIBSLIRF

Gas

Line (nm)

LoD (wt.%)

LoQ (wt.%)

R2

RMSECV (wt.%)

Air Air

193.1 247.9

0.060 -

0.200 -

0.871 0.088

0.226 -

N2

388.3

0.013

0.043

0.991

0.046

Air

388.3

0.039

0.130

0.974

0.078

The conventional methods and LIBS-LIRF in carbon determination were compared in Table 3. After developing for decades, the conventional methods have better analytical performances than LIBS-LIRF in this work. However, these ex-


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Analytical Chemistry Table 3. Comparison of conventional methods and LIBS-LIRF in carbon determination

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Titrimetry1,2 SS-AES3 PIGE4,5 LIBS21-29 LIBS-LIRF

LoD

Gas

Sample preparation

Response time

Distance

Online detection

Wt.10-4 Wt.10-5 Wt.10-5 Wt.10-5 Wt.10-4

Air Vacuum/He/Ar in whole probes Vacuum/He/Ar in whole probes Vacuum/He/Ar in whole probes Air/N2 on samples

Complicated Simple Simple Dispensable Dispensable

Minutes Minutes Seconds Seconds Seconds

None Millimeters Millimeters Tunable Tunable

Unavailable Unavailable Unavailable Unavailable Available

isting methods are not suitable for online detection, because of complicated operation, lengthy process, or short detective distance. In contrast, the proposed method LIBS-LIRF has incomparable advantages of rapid response, tunable detective distance, in-situ detection no or simple sample preparation, and small detection spot, which provide LIBS-LIRF great potentials and competitiveness in online detection. Sensitivity improvement of LIBS-LIRF is the key of our further work.

CONCLUSIONS In this work, a novel approach was established to determine carbon contents in steels using laser-induced CN radical fluorescence in LIBS. Different from conventional LIBS-LIF, LIBS-LIRF in this work takes CN radicals as the resonantly excited targets. The results show that CN emission intensity in LIBS-LIRF was two orders of magnitude stronger than that in LIBS. For the carbon determination in steels, R2 values of 0.991 and 0.974, LoDs of 0.013 and 0.039 wt.%, LoQs of 0.043 and 0.130 wt.%, were achieved using LIBS-LIRF in nitrogen gas and air, respectively, which are significantly better than those in atomic LIBS. This work opens up a new area for LIBS to realize a highly accurate and sensitive determination of carbon contents in steels. It also suggests that radical excitation is a meaningful alternative when atomic excitation is not available in LIBS-LIF.

AUTHOR INFORMATION Corresponding Author * Phone: 86-27-87544774. Fax: +86-27-87541423. E-mail: [email protected]

Author Contributions The manuscript was written with contributions of all authors. All authors have given approval to the final version of the manuscript.

Notes The authors declare no competing financial interest.

ACKNOWLEDGMENT National Instrumentation Program of China (No. 2011YQ160017) and National Natural Science Foundation of China (No. 61575073).

REFERENCES (1) Jones, R.; Gale, P.; Hopkins, P.; Powell, L. Analyst 1965, 90, 623629. (2) Boniface, H.; Jenkins, R. Analyst 1971, 96, 37-46. (3) Song, Z.-f.; Mou, X.-y.; Cheng, J.-p.; Cheng, X.-f.; Zhang, P. Metallurgical Analysis 2008, 10, 003. (4) Ene, A.; Popescu, I.; Badica, T. J Optoelectron Adv M 2006, 8, 222-224. (5) Xu, Y.; Xu, M.; Wang, G.-F.; Zheng, C.-L.; Qiu, M.-L.; Chu, Y.J. Nuclear Science and Techniques 2016, 27, 137.

(6) Sun, L. X.; Yu, H. B.; Cong, Z. B.; Xin, Y.; Li, Y.; Qi, L. F. Spectrochim Acta B 2015, 112, 40-48. (7) Singh, J. P.; Thakur, S. N. Laser-induced breakdown spectroscopy; Elsevier, 2007. (8) Li, J. M.; Guo, L. B.; Li, C. M.; Zhao, N.; Yang, X. Y.; Hao, Z. Q.; Li, X. Y.; Zeng, X. Y.; Lu, Y. F. Opt. Lett. 2015, 40, 5224-5226. (9) Wang, Z.; Yuan, T. B.; Hou, Z. Y.; Zhou, W. D.; Lu, J. D.; Ding, H. B.; Zeng, X. Y. Frontiers of Physics 2014, 9, 419-438. (10) Popov, A. M.; Colao, F.; Fantoni, R. J. Anal. At. Spectrom. 2010, 25, 837-848. (11) Martin, M. Z.; Allman, S.; Brice, D. J.; Martin, R. C.; Andre, N. O. Spectrochim Acta B 2012, 74-75, 177-183. (12) Lee, S. H.; Shim, H. S.; Kim, C. K.; Yoo, J. H.; Russo, R. E.; Jeong, S. Appl. Opt. 2012, 51, B115-B120. (13) Li, J.; Guo, L.; Zhao, N.; Chen, Q.; Wu, B.; Wang, Y.; Li, X.; Li, J.; Zeng, X.; Lu, Y. J. Anal. At. Spectrom. 2016, 31, 492-496. (14) Vaniman, D.; Dyar, M.; Wiens, R.; Ollila, A.; Lanza, N.; Lasue, J.; Rhodes, J.; Clegg, S.; Newsom, H. Space science reviews 2012, 170, 229-255. (15) Giakoumaki, A.; Melessanaki, K.; Anglos, D. Anal. Bioanal. Chem. 2007, 387, 749-760. (16) Noda, M.; Deguchi, Y.; Iwasaki, S.; Yoshikawa, N. Spectrochim. Acta, Part B 2002, 57, 701-709. (17) Yuan, T.; Wang, Z.; Li, Z.; Ni, W.; Liu, J. Anal. Chim. Acta 2014, 807, 29-35. (18) Abdulmadjid, S. N.; Idris, N.; Pardede, M.; Jobiliong, E.; Hedwig, R.; Lie, Z. S.; Suyanto, H.; Tjia, M. O.; Kurniawan, K. H.; Kagawa, K. Spectrochim Acta B 2015, 114, 1-6. (19) Li, X.; Wang, Z.; Fu, Y.; Li, Z.; Liu, J.; Ni, W. Appl. Spectrosc. 2014, 68, 955-962. (20) Zaytsev, S. M.; Popov, A. M.; Zorov, N. B.; Labutin, T. A. Spectrochim Acta B 2016, 118, 37-44. (21) Jiang, X.; Hayden, P.; Laasch, R.; Costello, J. T.; Kennedy, E. T. Spectrochim Acta B 2013, 86, 66-74. (22) Jiang, X.; Hayden, P.; Costello, J. T.; Kennedy, E. T. Spectrochim Acta B 2014, 101, 106-113. (23) Sturm, V.; Peter, L.; Noll, R. Appl. Spectrosc. 2000, 54, 12751278. (24) Aragon, C.; Aguilera, J.; Campos, J. Appl. Spectrosc. 1993, 47, 606-608. (25) Aragon, C.; Aguilera, J. A.; Penalba, F. Appl. Spectrosc. 1999, 53, 1259-1267. (26) Khater, M. A.; Costello, J. T.; Kennedy, E. T. Appl. Spectrosc. 2002, 56, 970-983. (27) Khater, M. A.; van Kampen, P.; Costello, J. T.; Mosnier, J. P.; Kennedy, E. T. J Phys D Appl Phys 2000, 33, 2252-2262. (28) Hemmerlin, M.; Meilland, R.; Falk, H.; Wintjens, P.; Paulard, L. Spectrochim Acta B 2001, 56, 661-669. (29) Peter, L.; Sturm, V.; Noll, R. Appl. Opt. 2003, 42, 6199-6204. (30) Labutin, T. A.; Zaytsev, S. M.; Popov, A. M.; Zorov, N. B. Opt. Express 2014, 22, 22382-22387. (31) Goueguel, C.; Laville, S.; Loudyi, H.; Chaker, M.; Sabsabi, M.; Vidal, F. In Photonics North 2008; International Society for Optics and Photonics: Montréal, 2008, p 709927. (32) Loudyi, H.; Rifai, K.; Laville, S.; Vidal, F.; Chaker, M.; Sabsabi, M. J. Anal. At. Spectrom. 2009, 24, 1421-1428. (33) Laville, S.; Goueguel, C.; Loudyi, H.; Vidal, F.; Chaker, M.; Sabsabi, M. Spectrochim. Acta, Part B 2009, 64, 347-353. (34) Li, J.; Guo, L.; Zhao, N.; Yang, X.; Yi, R.; Li, K.; Zeng, Q.; Li, X.; Zeng, X.; Lu, Y. Talanta 2016, 151, 234-238.



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(35) Gornushkin, I.; Kim, J.; Smith, B.; Baker, S.; Winefordner, J. Appl. Spectrosc. 1997, 51, 1055-1059. (36) Kondo, H.; Hamada, N.; Wagatsuma, K. Spectrochim. Acta, Part B 2009, 64, 884-890. (37) Shen, X. K.; Wang, H.; Xie, Z. Q.; Gao, Y.; Ling, H.; Lu, Y. F. Appl. Opt. 2009, 48, 2551-2558. (38) Li, C.; Hao, Z.; Zou, Z.; Zhou, R.; Li, J.; Guo, L.; Li, X.; Lu, Y.; Zeng, X. Opt. Express 2016, 24, 7850-7857. (39) Li, J.-M.; Chu, Y.-B.; Zhao, N.; Zhou, R.; Yi, R.-X.; Guo, L.-B.; Li, J.-Y.; Li, X.-Y.; Zeng, X.-Y.; Lu, Y.-F. Chinese J Anal Chem 2016, 44, 1042-1046. (40) Hilbk-Kortenbruck, F.; Noll, R.; Wintjens, P.; Falk, H.; Becker, C. Spectrochim. Acta, Part B 2001, 56, 933-945. (41) Yao, S. C.; Shen, Y. L.; Yin, K. J.; Pan, G.; Lu, J. D. Energy Fuels 2015, 29, 1257-1263. (42) Li, X. W.; Yin, H. L.; Wang, Z.; Fu, Y. T.; Li, Z.; Ni, W. D. Spectrochim Acta B 2015, 111, 102-107.

Page 6 of 16

(43) Baudelet, M.; Guyon, L.; Yu, J.; Wolf, J. P.; Amodeo, T.; Frejafon, E.; Laloi, P. Appl. Phys. Lett. 2006, 88. (44) Yu, Y.; Guo, L. B.; Hao, Z. Q.; Li, X. Y.; Shen, M.; Zeng, Q. D.; Li, K. H.; Zeng, X. Y.; Lu, Y. F.; Ren, Z. Opt. Express 2014, 22, 3895-3901. (45) Knowles, P. J.; Werner, H. J.; Hay, P. J.; Cartwright, D. C. The Journal of Chemical Physics 1988, 89, 7334-7343. (46) Pearse, R. W. B.; Gaydon, A. G.; Pearse, R. W. B.; Gaydon, A. G. The identification of molecular spectra; Chapman and Hall London, 1976; Vol. 297. (47) Li, J.; Hao, Z.; Zhao, N.; Zhou, R.; Yi, R.; Tang, S.; Guo, L.; Li, X.; Zeng, X.; Lu, Y. Opt. Express 2017, 25, 4945-4951.


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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 ACS Paragon Plus Environment


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Figure 1. Schematic diagram of LIBS-LIRF experimental process: breakdown (a), atomization (b), combination (c), and excitation (d) 428x357mm (150 x 150 DPI)


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Figure 2. Schematic diagram of the experimental setup. 228x181mm (150 x 150 DPI)



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Figure. 3. Schematic diagram of LIRF in CN radicals 161x78mm (150 x 150 DPI)


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Figure 4. B2Σ+-X2Σ+ (0,0) spectra of the PVC sample using LIBS (black line) and LIBS-LIRF (blue line). 288x201mm (300 x 300 DPI)



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Figure 5. Synchronicity between OPO laser and CN fluorescence of B2Σ+-X2Σ+ (0,0) in LIBS-LIRF. 288x201mm (300 x 300 DPI)


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Figure 6. CN B2Σ+-X2Σ+ (0,0) 388.34 nm signals acquired by LIBS in air (black line), LIBS in nitrogen (green line), LIBS-LIRF in air (blue line), and LIBS-LIRF in nitrogen (red line). 288x201mm (300 x 300 DPI)



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Figure 7. Influences of the interpulse delays on CN B2Σ+-X2Σ+ (0,0) fluorescence intensity acquired by LIBS-LIRF in air (blue scatters and line) and nitrogen (red scatters and line); and the ratio (green scatters and line) between fluorescence intensity in nitrogen and air. 297x207mm (300 x 300 DPI)


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Figure 8. (a) Internal calibration curves of carbon in steels meas-ured by LIBS with atomic lines 193.1 nm (purple scatters and line) and 247.9 nm (orange scatters and line) 288x201mm (300 x 300 DPI)



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Figure 8(b) internal calibration curves of carbon in steels measured by LIBS-LIRF in nitrogen gas (red scatters and line) and air (blue scatters and line). 288x201mm (300 x 300 DPI)


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Determination of Carbon Content in Steels Using Laser-Induced

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