title: Non-gated laser induced breakdown spectroscopy provides a powerful segmentation tool on concomitant treatment of characteristic and continuum emission.
abstract: We demonstrate the application of non-gated laser induced breakdown spectroscopy (LIBS) for characterization and classification of organic materials with similar chemical composition. While use of such a system introduces substantive continuum background in the spectral dataset, we show that appropriate treatment of the continuum and characteristic emission results in accurate discrimination of pharmaceutical formulations of similar stoichiometry. Specifically, our results suggest that near-perfect classification can be obtained by employing suitable multivariate analysis on the acquired spectra, without prior removal of the continuum background. Indeed, we conjecture that pre-processing in the form of background removal may introduce spurious features in the signal. Our findings in this report significantly advance the prior results in time-integrated LIBS application and suggest the possibility of a portable, non-gated LIBS system as a process analytical tool, given its simple instrumentation needs, real-time capability and lack of sample preparation requirements.
authors.affiliation: Advanced Centre of Research in High Energy Materials (ACRHEM), University of Hyderabad, Gachibowli, Hyderabad, Andhra Pradesh, India.
authors.forename: Ashwin Kumar
authors.initials: AK
authors.lastname: Myakalwar
authors.affiliation: Laser Biomedical Research Center, G. R. Harrison Spectroscopy Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America.
authors.forename: Narahara Chari
authors.initials: NC
authors.lastname: Dingari
authors.affiliation: Laser Biomedical Research Center, G. R. Harrison Spectroscopy Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America.
authors.forename: Ramachandra Rao
authors.initials: RR
authors.lastname: Dasari
authors.affiliation: Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: Ishan
authors.initials: I
authors.lastname: Barman
authors.affiliation: Advanced Centre of Research in High Energy Materials (ACRHEM), University of Hyderabad, Gachibowli, Hyderabad, Andhra Pradesh, India.
authors.forename: Manoj Kumar
authors.initials: MK
authors.lastname: Gundawar
mesh_terms: D007834:Lasers; D013057:Spectrum Analysis / Q000379:methods*
references.citation: Talanta. 2011 Dec 15;87:53-9
references.pmid: 22099648
references.citation: Anal Chem. 2012 Mar 20;84(6):2686-94
references.pmid: 22292496
references.citation: J Biomed Opt. 2011 Jan-Feb;16(1):011004
references.pmid: 21280891
references.citation: Pharm Res. 2007 Jan;24(1):58-65
references.pmid: 17048116
references.citation: Appl Spectrosc. 2003 Nov;57(11):1363-7
references.pmid: 14658149
references.citation: Anal Chem. 2012 Sep 18;84(18):7938-45
references.pmid: 22894881
references.citation: Anal Chem. 2007 Jun 15;79(12):4419-26
references.pmid: 17503765
references.citation: Anal Chem. 2010 Jul 15;82(14):6273-80
references.pmid: 20568722
references.citation: Anal Chem. 2010 Feb 15;82(4):1389-400
references.pmid: 20085236
references.citation: Anal Chem. 2006 Mar 1;78(5):1462-9
references.pmid: 16503595
references.citation: Analyst. 2009 Jun;134(6):1198-202
references.pmid: 19475148
references.citation: Appl Spectrosc. 2010 Dec;64(12):335-66
references.pmid: 21144145
references.citation: Anal Bioanal Chem. 2006 Mar;384(5):1036-42
references.pmid: 16079977