Analysis of White Latex Paints using Laser Induced Breakdown Spectroscopy for Forensic Applications

The analysis of white latex paint is a problem for forensic laboratories because of difficulty in differentiation between samples. Current methods provide limited information that is not suitable for discrimination. Elemental analysis of white latex paints has resulted in 99% discriminating power when using LA-ICP-MS; however, mass spectrometers can be prohibitively expensive and require a skilled operator. A quick, inexpensive, effective method is needed for the differentiation of white latex paints. In this study, LIBS is used to analyze 24 white latex paint samples. LIBS is fast, easy to operate, and has a low cost. Results show that 98.1% of variation can be accounted for via principle component analysis, while Tukey pairwise comparisons differentiated 95.6% with potassium as the elemental ratio, showing that the discrimination capabilities of LIBS are comparable to those of LA-ICP-MS. Due to the many advantages of LIBS, this instrument should be considered a necessity for forensic laboratories

The Grizzly, February 3, 1997

Alumni Donate $1 Million for Renovation of Pfahler Hall • Ursinus Faculty Members Publish Books / Articles • Gender Studies to be Considered • Meistersingers Perform • Changes in Study Abroad Aim to Ease Students\u27 Minds and Pockets: Part I of II • Diversity Week • Opinion: Return to Never-Never Land; 2 Steps 2 Save; Theatre as we Like it; A Question of Security, Take Two; Todd-onics; Seven Steps to a Better Opinions Article • Sigma Chi Delta Extends Invitation for New Members • Hinckle Named to AP Little America First Team • Coach Gilbert: The Man, The Myth, The Legend • Ursinus to Host International Wrestling Match • Men\u27s Basketball Team Loses to Washington and Falls to 4-13 • Whelan and Knothe Score Individual Wins for UC Swim Teams • Wrestling Bears Roar to 14-1 Mark • Gymnasts Set Team Scoring Record • Lady Bears Continue Winning Wayshttps://digitalcommons.ursinus.edu/grizzlynews/1395/thumbnail.jp

Evaluation of Forest Disturbance Legacy Effects on Dissolved Organic Matter Characteristics in Streams at the Hubbard Brook Experimental Forest, New Hampshire

Dissolved organic matter (DOM) source and composition are critical drivers of its reactivity, impact microbial food webs and influence ecosystem functions. It is believed that DOM composition and abundance represent an integrated signal derived from the surrounding watershed. Recent studies have shown that land-use may have a long-term effect on DOM composition. Methods for characterizing DOM, such as those that measure the optical properties and size of the molecules, are increasingly recognized as valuable tools for assessing DOM sources, cycling, and reactivity. In this study we measured DOM optical properties and molecular weight determinations to evaluate whether the legacy of forest disturbance alters the amount and composition of stream DOM. Differences in DOM quantity and composition due to vegetation type and to a greater extent, wetland influence, were more pronounced than effects due to disturbance. Our results suggest that excitation-emission matrix fluorescence with parallel factor analysis is a more sensitive metric of disturbance than the other methods evaluated. Analyses showed that streams draining watersheds that have been clearcut had lower dissolved organic carbon (DOC) concentrations and higher microbially-derived and protein-like fluorescence features compared to reference streams. DOM optical properties in a watershed amended with calcium, were not significantly different than reference watersheds, but had higher concentrations of DOC. Collectively these results improve our understanding of how the legacy of forest disturbances and natural landscape characteristics affect the quantity and chemical composition of DOM in headwater streams, having implications for stream water quality and carbon cycling