title: Label-free surface-enhanced Raman scattering strategy for rapid detection of penicilloic acid in milk products.
abstract: A label-free surface-enhanced Raman scattering (SERS) strategy based on silver-coated gold nanoparticles (Au@Ag NPs) was developed for rapid detection of penicilloic acid (PA) in milk products. It has been demonstrated that core size and shell thickness of Au@Ag NPs are two critical variants affecting enhancement of Raman signals by coupling of two plasma resonance absorption. The Au@Ag NPs with 26-nm core and 9-nm Ag shell exhibit excellent Raman enhancement, in particular, upon the formation of hot spots through NPs aggregation induced by interaction between target molecules and Au@Ag NPs. Compared to the early studies limited to laboratory settings, our analytical approach is simple (without sample pretreatment), less time-consuming (within ∼3 min) and inexpensive. The limit of detection of PA is 3.00 ppm, 3.00 ppm and 4.00 ppm in liquid milk, yogurt and milk powder, respectively. The label-free SERS technique offers a potential for the on-site monitoring of chemical contaminants in milk products.
authors.affiliation: School of Pharmacy, Nanjing Medical University, Nanjing, Jiangsu 211166, China.
authors.forename: Meihui
authors.initials: M
authors.lastname: Qi
authors.affiliation: School of Pharmacy, Nanjing Medical University, Nanjing, Jiangsu 211166, China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Huang
authors.affiliation: School of Pharmacy, Nanjing Medical University, Nanjing, Jiangsu 211166, China.
authors.forename: Yujie
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: School of Pharmacy, Nanjing Medical University, Nanjing, Jiangsu 211166, China.
authors.forename: Liying
authors.initials: L
authors.lastname: Zhang
authors.affiliation: School of Pharmacy, Nanjing Medical University, Nanjing, Jiangsu 211166, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Jin
authors.affiliation: School of Pharmacy, Nanjing Medical University, Nanjing, Jiangsu 211166, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Peng
authors.affiliation: School of Pharmacy, Nanjing Medical University, Nanjing, Jiangsu 211166, China.
authors.forename: Huijun
authors.initials: H
authors.lastname: Jiang
authors.affiliation: School of Pharmacy, Nanjing Medical University, Nanjing, Jiangsu 211166, China. Electronic address: shuhudu@njmu.edu.cn.
authors.forename: Shuhu
authors.initials: S
authors.lastname: Du
mesh_terms: D000818:Animals; D005504:Food Analysis / Q000295:instrumentation / Q000379:methods*; D005506:Food Contamination / Q000032:analysis*; D006046:Gold / Q000737:chemistry; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry; D008892:Milk / Q000737:chemistry*; D010397:Penicillanic Acid / Q000031:analogs & derivatives* / Q000032:analysis; D012834:Silver / Q000737:chemistry; D013059:Spectrum Analysis, Raman / Q000379:methods*
chemical_list: C008782:penicilloic acid; D012834:Silver; D006046:Gold; D010397:Penicillanic Acid
keywords: Core-shell nanoparticles; Milk products; Penicilloic acid; Surface-enhanced Raman scattering