{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T02:02:21Z","timestamp":1760234541680,"version":"build-2065373602"},"reference-count":30,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2021,5,28]],"date-time":"2021-05-28T00:00:00Z","timestamp":1622160000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001691","name":"Japan Society for the Promotion of Science","doi-asserted-by":"publisher","award":["JP 20H00231","JP 20K12615"],"award-info":[{"award-number":["JP 20H00231","JP 20K12615"]}],"id":[{"id":"10.13039\/501100001691","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>A laser-induced breakdown spectroscopy (LIBS) system using a microchip laser for plasma generation is proposed for in-situ analysis of trace minerals in human hair. The LIBS system is more compact and less expensive than conventional LIBS systems, which use flashlamp-excited Q-switched Nd:YAG lasers. Focusing optics were optimized using a Galilean beam expander to compensate for the low emitted pulse energy of the microchip laser. Additionally, hundreds of generated LIBS spectra were accumulated to improve the signal-to-noise ratio of the measurement system, and argon gas was injected at the irradiation point to enhance plasma intensity. LIBS spectra of human hair in the UV to near IR regions were investigated. Relative mass concentrations of Ca, Mg, and Zn were analyzed in hairs obtained from five subjects using the intensity of C as a reference. The results coincide well with those measured via inductively coupled argon plasma mass spectrometry. The lowest detectable concentrations of the measured LIBS spectra were 9.0 ppm for Mg, 27 ppm for Zn, and 710 ppm for Ca. From these results, we find that the proposed LIBS system based on a microchip laser is feasible for the analysis of trace minerals in human hair.<\/jats:p>","DOI":"10.3390\/s21113752","type":"journal-article","created":{"date-parts":[[2021,5,31]],"date-time":"2021-05-31T03:45:29Z","timestamp":1622432729000},"page":"3752","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Analysis of Trace Metals in Human Hair by Laser-Induced Breakdown Spectroscopy with a Compact Microchip Laser"],"prefix":"10.3390","volume":"21","author":[{"given":"Makoto","family":"Nakagawa","sequence":"first","affiliation":[{"name":"Graduate School of Engineering, Tohoku University, 6-6-05 Aoba, Sendai 980-8579, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4722-7654","authenticated-orcid":false,"given":"Yuji","family":"Matsuura","sequence":"additional","affiliation":[{"name":"Graduate School of Engineering, Tohoku University, 6-6-05 Aoba, Sendai 980-8579, Japan"},{"name":"Graduate School of Biomedical Engineering, Tohoku University, 6-6-05 Aoba, Sendai 980-8579, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,5,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Cremers, D.A., and Radziemski, L.J. (2006). Handbook of Laser-Induced Breakdown Spectroscopy, John Wiley & Sons.","DOI":"10.1002\/0470093013"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Musazzi, S., and Perini, U. (2014). Laser-Induced Breakdown Spectroscopy: Theory and Applications, Springer.","DOI":"10.1007\/978-3-642-45085-3"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"393","DOI":"10.1016\/S0925-8388(00)00647-2","article-title":"Passively Q-switched Nd: YAG microchip lasers and applications","volume":"46","author":"Zayhowski","year":"2000","journal-title":"J. Alloy. Compd."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"19891","DOI":"10.1364\/OE.16.019891","article-title":"1 MW peak power single-mode high-brightness passively Q-switched Nd3+: YAG microchip laser","volume":"16","author":"Sakai","year":"2008","journal-title":"Opt. Express"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"571","DOI":"10.1039\/C3JA50348H","article-title":"Optimizing gated detection in high-jitter kilohertz powerchip laser-induced breakdown spectroscopy","volume":"29","author":"Merten","year":"2014","journal-title":"J. Anal. At. Spectrom."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"50","DOI":"10.1016\/j.sab.2013.01.011","article-title":"Local thermodynamic equilibrium considerations in powerchip laser-induced plasmas","volume":"83\u201384","author":"Merten","year":"2013","journal-title":"Spectrochim. Acta Part B At. Spectrosc."},{"key":"ref_7","unstructured":"Singh, J.P., and Thakur, S.N. (2007). Laser-Induced Breakdown Spectroscopy, Elsevier."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"544","DOI":"10.1039\/b419109a","article-title":"Microchip laser ablation of metals: Investigation of the ablation process in view of its application to laser-induced breakdown spectroscopy","volume":"20","author":"Omenetto","year":"2005","journal-title":"J. Anal. At. Spectrom."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"762","DOI":"10.1366\/0003702041389427","article-title":"Microchip laser-induced breakdown spectroscopy: A preliminary feasibility investigation","volume":"58","author":"Gornushkin","year":"2004","journal-title":"Appl. Spectrosc."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"552","DOI":"10.1039\/b419173k","article-title":"Quantitative analysis of low-alloy steel by microchip laser induced breakdown spectroscopy","volume":"20","author":"Smith","year":"2005","journal-title":"J. Anal. At. Spectrom."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"20","DOI":"10.1016\/j.sab.2012.02.007","article-title":"A compact and low cost laser induced breakdown spectroscopic system: Application for simultaneous determination of chromium and nickel in steel using multivariate calibration","volume":"69","author":"Gonzaga","year":"2012","journal-title":"Spectrochim. Acta Pt. B At. Spec."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1076","DOI":"10.1016\/j.sab.2005.03.020","article-title":"Aluminum alloy analysis using microchip-laser induced breakdown spectroscopy","volume":"60","author":"Freedman","year":"2005","journal-title":"Spectrochim. Acta Pt. B At. Spec."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"697","DOI":"10.1039\/b604628b","article-title":"Quantitative analysis of aluminium alloys by low-energy, high-repetition rate laser-induced breakdown spectroscopy","volume":"21","author":"Cristoforetti","year":"2006","journal-title":"J. Anal. At. Spectrom."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"123","DOI":"10.1016\/j.sab.2018.11.006","article-title":"Laser-induced breakdown spectroscopy for human and animal health: A review","volume":"152","author":"Gaudiuso","year":"2019","journal-title":"Spectrochim. Acta Pt. B At. Spec."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Thompson, M., and Walsh, J.N. (1989). Handbook of Inductively Coupled Plasma Spectrometry, Springer. [2nd ed.].","DOI":"10.1007\/978-1-4613-0697-9"},{"key":"ref_16","first-page":"131","article-title":"A review of the capabilities of ICP-MS for trace element analysis in body fluids and tissues","volume":"7","author":"Vanhoe","year":"1993","journal-title":"J. Trace Elem. Electrol. Health Dis."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"054701","DOI":"10.1063\/1.4747934","article-title":"A study of association between fingernail elements and osteoporosis by laser-induced breakdown spectroscopy","volume":"112","author":"Bahreini","year":"2012","journal-title":"J. Appl. Phys."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"057002","DOI":"10.1117\/1.3574757","article-title":"Analysis of human nails by laser-induced breakdown spectroscopy","volume":"16","author":"Hosseinimakarem","year":"2011","journal-title":"J. Biomed. Opt."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"79","DOI":"10.1007\/s10103-010-0821-x","article-title":"Quantitative analysis of pathological nails using laser-induced breakdown spectroscopy (LIBS) technique","volume":"26","author":"Hamzaoui","year":"2011","journal-title":"Lasers Med. Sci."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"107006","DOI":"10.1117\/1.JBO.18.10.107006","article-title":"Discrimination of patients with diabetes mellitus and healthy subjects based on laser-induced breakdown spectroscopy of their fingernails","volume":"18","author":"Bahreini","year":"2013","journal-title":"J. Biomed. Opt."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Haruna, M., Ohmi, M., Nakamura, M., and Morimoto, S. Calcium detection of human hair and nail by the nanosecond time-gated spectroscopy of laser-ablation plume. SPIE 3917, Optical Biopsy II, Proceedings of the BiOS 2000 The International Symposium on Biomedical Optics, San Jose, CA, USA, 22 January 2000, SPIE Press.","DOI":"10.1117\/12.382719"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"6133","DOI":"10.1364\/AO.42.006133","article-title":"Application of laser-induced breakdown spectroscopy technique to hair tissue mineral analysis","volume":"42","author":"Corsi","year":"2003","journal-title":"Appl. Opt."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"176","DOI":"10.1016\/j.talanta.2013.08.043","article-title":"Biological application of laser induced breakdown spectroscopy technique for determination of trace elements in hair","volume":"117","author":"Emara","year":"2013","journal-title":"Talanta"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"105018","DOI":"10.1016\/j.microc.2020.105018","article-title":"Highly accurate determination of Zn and Cu in human hair by ultrasound-assisted alkali dissolution combined with laser-induced breakdown spectroscopy","volume":"157","author":"Zhang","year":"2020","journal-title":"Microchem. J."},{"key":"ref_25","first-page":"845","article-title":"Quantification of elements in hair standard data by neutron activation analysis","volume":"43","author":"Araki","year":"1994","journal-title":"Bunseki Kagaku (Anal. Chem.)"},{"key":"ref_26","unstructured":"(2020, December 15). NIST: Atomic Spectra Database Lines Form, Available online: https:\/\/physics.nist.gov\/PhysRefData\/ASD\/LIBS\/libs-form.html."},{"key":"ref_27","unstructured":"Delaware State University (2021, January 18). LIBS Database\u2013Optical Science Center for Applied Research. Available online: https:\/\/oscar.desu.edu\/libs\/."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"015702","DOI":"10.1088\/0031-8949\/85\/01\/015702","article-title":"Effect of ambient gas conditions on laser-induced copper plasma and surface morphology","volume":"85","author":"Farid","year":"2012","journal-title":"Phys. Scr."},{"key":"ref_29","unstructured":"(2020, December 12). Kyorin Preventive Medicine Institute, Hair Mineral Analysis. (In Japanese)."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"429","DOI":"10.1039\/b315606k","article-title":"Quantitative laser induced breakdown spectroscopy analysis of ancient marbles and corrections for the variability of plasma parameters and of ablation rate","volume":"19","author":"Lazic","year":"2004","journal-title":"J. Anal. At. Spectrom."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/11\/3752\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T06:09:45Z","timestamp":1760162985000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/11\/3752"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,5,28]]},"references-count":30,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2021,6]]}},"alternative-id":["s21113752"],"URL":"https:\/\/doi.org\/10.3390\/s21113752","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2021,5,28]]}}}