Journal: Analytical and Bioanalytical Chemistry

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2 articles found

Combining Raman and laser induced breakdown spectroscopy by double pulse lasing

Author: Lednev, V. N. ; et. al.

Journal: Analytical and Bioanalytical Chemistry (2018)

DOI: 10.1007/s00216-017-0719-6

Authors
Bukin, V. V. ; Fedorov, A. N. ; Grishin, M. Y. ; Oshurko, V. B. ; Pershin, S. M. ; Sdvizhenskii, P. A. ; Shchegolikhin, A. N.

Keywords

Laser induced breakdown spectroscopy; LIBS; Raman scattering; Double pulse; Quantitative analysis;QUANTITATIVE-ANALYSIS; LIBS; SPECTROMETER; MICROSCOPY; MINERALS; PIGMENTS; PLATFORM; ASPIRIN; SYSTEM; CRATER

Abstract

A new approach combining Raman spectrometry and laser induced breakdown spectrometry (LIBS) within a single laser event was suggested. A pulsed solid state Nd:YAG laser running in double pulse mode (two frequency-doubled sequential nanosecond laser pulses with dozens microseconds delay) was used to combine two spectrometry methods within a single instrument (Raman/LIBS spectrometer). First, a low-energy laser pulse (power density far below ablation threshold) was used for Raman measurements while a second powerful laser pulse created the plasma suitable for LIBS analysis. A short time delay between two successive pulses allows measuring LIBS and Raman spectra at different moments but within a single laser flash-lamp pumping. Principal advantages of the developed instrument include high quality Raman/LIBS spectra acquisition (due to optimal gating for Raman/LIBS independently) and absence of target thermal alteration during Raman measurements. A series of high quality Raman and LIBS spectra were acquired for inorganic salts (gypsum, anhydrite) as well as for pharmaceutical samples (acetylsalicylic acid). To the best of our knowledge, the quantitative analysis feasibility by combined Raman/LIBS instrument was demonstrated for the first time by calibration curves construction for acetylsalicylic acid (Raman) and copper (LIBS) in gypsum matrix. Combining ablation pulses and Raman measurements (LIBS/Raman measurements) within a single instrument makes it an efficient tool for identification of samples hidden by non-transparent covering or performing depth profiling analysis including remote sensing.

Area:

Pharmaceutics

Material:

Acetylsalicylic acid ; Anhydrite ; Gypsum

Elements:

Lines [nm]:

Ca II 317.93 nm Ca II 393.37 nm Ca II 396.85 nm Ca I 364.44 nm Ca I 422.67 nm Ca I 443.50 nm Ca I 445.48 nm Ca I 487.81 nm Ca I 504.16 nm Ca I 518.89 nm Ca I 526.56 nm Ca I 559.45 nm Ca I 616.96 nm Ca I 646.26 nm

Lines [nm]:

Na I 589.00 nm Na I 589.59 nm

Lines [nm]:

H I 656.28 nm

Lines [nm]:

S I 469.41 nm

Lines [nm]:

Cu I 352.42 nm

Emmision lines:
Ca II 317.93 nm
Cu I 352.42 nm
Ca I 364.44 nm
Ca II 393.37 nm
Ca II 396.85 nm
Ca I 422.67 nm
Ca I 443.50 nm
Ca I 445.48 nm
S I 469.41 nm
Ca I 487.81 nm
Ca I 504.16 nm
Ca I 518.89 nm
Ca I 526.56 nm
Ca I 559.45 nm
Na I 589.00 nm
Na I 589.59 nm
Ca I 616.96 nm
Ca I 646.26 nm
H I 656.28 nm

A hybrid LIBS-Raman system combined with chemometrics: an efficient tool for plastic identification and sorting

Author: Shameem, K. M. M. ; et. al.

Journal: Analytical and Bioanalytical Chemistry (2017)

Applications Chemometrics

DOI: 10.1007/s00216-017-0268-z

Authors
Bankapur, A. ; George, S. D. ; Choudhari, K. S. ; Kartha, V. B. ; Kulkarni, S. D. ; Santhosh, C. ; Unnikrishnan, V. K.

Keywords

Laser ablation; Raman spectroscopy; Chemometrics; Complementarity; Polymers;INDUCED BREAKDOWN SPECTROSCOPY; INDUCED PLASMA SPECTROSCOPY; ARTIFICIAL NEURAL-NETWORKS; POLYMER IDENTIFICATION; CLASSIFICATION; MICROSCOPY; PIGMENTS; SPECTRA; COPPER; NIR

Abstract

Classification of plastics is of great importance in the recycling industry as the littering of plastic wastes increases day by day as a result of its extensive use. In this paper, we demonstrate the efficacy of a combined laser-induced breakdown spectroscopy (LIBS)-Raman system for the rapid identification and classification of post-consumer plastics. The atomic information and molecular information of polyethylene terephthalate, polyethylene, polypropylene, and polystyrene were studied using plasma emission spectra and scattered signal obtained in the LIBS and Raman technique, respectively. The collected spectral features of the samples were analyzed using statistical tools (principal component analysis, Mahalanobis distance) to categorize the plastics. The analyses of the data clearly show that elemental information and molecular information obtained from these techniques are efficient for classification of plastics. In addition, the molecular information collected via Raman spectroscopy exhibits clearly distinct features for the transparent plastics (100% discrimination), whereas the LIBS technique shows better spectral feature differences for the colored samples. The study shows that the information obtained from these complementary techniques allows the complete classification of the plastic samples, irrespective of the color or additives. This work further throws some light on the fact that the potential limitations of any of these techniques for sample identification can be overcome by the complementarity of these two techniques.

Area:

Industry

Material:

Plastics

Elements:

Emmision lines:

Journal: Analytical and Bioanalytical Chemistry

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