Date/Time
Date(s) – 09/28/2017
6:00 pm – 7:50 pm
Location
The Shevchenko Scientific Society
Category(ies) No Categories
Thursday September 28, 2017, 6 PM
Opening our New York Microscopical Society’s 2017-2018 Program:
Discrimination and Classification of Nail and Gel Polishes by Microscopic and Microspectroscopic Analytical Methods
Speaker and co-author:
University of New Haven, West Haven, CT
Co-Authors: Nicole Bois, MS1; Kaitlyn Clement, BS1; Audriana Wagner, MS1; Alyssa Smale2; Elaine Pagliaro, JD3; Donald Dahlberg, Ph.D.2
1Henry C. Lee College of Criminal Justice and Forensic Sciences, Dept of Forensic Science, University of New Haven, 300 Boston Post Rd, West Haven, CT 06516
2 Lebanon Valley College, 101 N. College Avenue, Annville, PA 17003-1400
3 The Henry Lee Institute of Forensic Science, University of New Haven, 300 Boston Post Rd, West Haven, CT 06516 2.
Abstract
Nail polish is a popular type of cosmetic evidence that is analyzed by trace evidence examiners with a similar methodology as paint evidence. Although there have been many studies to understand the evidentiary significance of paint evidence, the same cannot be said for nail polishes. Still, nail polish identification and discrimination has played a role in criminal cases, most notably the infamous woodchipper murder. Nail polish is a quick-drying lacquer, either clear or colored, used to paint fingernails or toenails. It contains multiple materials and is relatively complex.
This research focuses on the characterization and discrimination of both traditional nail polishes and the more modern gel polishes. For both types of polishes, color (pink and red) and clear (top and bottom) coats were studied. All of the color coats were chosen to be as similar in color as possible for the same brand as well as between brands. Seven colors from 7 different brands for each type of polish were selected resulting in a total of 98 color polishes. For 13 of the 14 brands, top and bottom coats were obtained resulting in the analysis of 26 different clear coats. The brands used were a mix of salon quality and ones intended for at-home use.
Raman, FT-IR and UV-Vis microspectroscopy in addition to stereomicroscopy, brightfield microscopy, polarized light microscopy and SEM-EDX were used to analyze the samples and gain information on their physical, optical, and chemical properties. Several multivariate statistical analysis methods, including principle component analysis (PCA), canonical variate analysis (CVA), and K-nearest neighbor modeling were used to assess the discrimination ability of the Raman and FT-IR spectroscopic methods.
In addition, real world nail and gel polish samples were analyzed to simulate actual samples that could be received in a forensic laboratory and to analyze the layer structure of the polish.
Free and open to the public, at:
The Shevchenko Scientific Society
63 Fourth Avenue, betw 9 & 10 Sts
Auditorium, 2nd floor
New York, NY 10003-5200