Giuseppe A. Petrucci

Analytical Chemistry and Aerosols Analysis

Associate Professor

Giuseppe.Petrucci@uvm.edu
phone: 802-656-0957
office: Cook Rm A218

The research interests of our group lie in the general field of aerosol analysis. Present investigations involve the simultaneous physical and chemical characterization of individual particles, leading to the rapid, on-line physico-chemical characterization of the aerosol.

The importance of aerosol science has increased dramatically in recent years. Aerosols contribute to a variety of environmental, biological, and industrial processes including air pollution (acid deposition, global warming), human health (morbidity, mortality, medicine delivery), combustion (soot and soot precursors), materials synthesis (nanoparticles, coatings) and clean room technology (quality control). Of particular interest is the adoption of the National Ambient Air Quality Standard (PM2.5) that discriminates aerosol toxicity on the basis of aerodynamic particle diameters. In addition, particle-bound toxins, such as polyaromatic hydrocarbons (PAHs) or dioxins, may exhibit enhanced toxicological behavior in the particle phase as opposed to the gas phase.

Our group is developing an instrument for the real-time physical and chemical characterization of aerosols on a single particle basis. This technique involves laser desorption/ionization of particles followed by time-of-flight mass spectrome-try. The aerosol mass spectrometer (AMS) shown below consists of 3 components: 1) particle inlet; 2) laser ionization laser; 3) mass spectrometer. The particle inlet can simultaneously collimate an aerosol into a compact beam and selectively sample particles of a pre-determined diameter. This selectivity provides an inherent means of particle size determi-nation. Once the particles have been sized, individual particles are vaporized into ionic components with a pulsed, high-power laser. The representative positive and negative ion bursts are then identified by bipolar time-of-flight mass spectrometry. In this manner, we obtain a correlated description of the aerodynamic size and chemical composition of single particles. With rapid, replicate measurements, these single particle analyses provide a detailed description of the entire aerosol sample.

Presently our research follows two general directions: ultrafine (sub-200 nm diameter) particle detection and the chemical analysis of particle-bound organic molecules. Both types of particles exhibit a high potential for human toxicity. The detection of ultrafine particles is a challenge that tests the pressure-dependent selectivity of the inlet. An extensive characterization of the inlet is necessary for the preferential, efficient, and reproducible sampling of ultrafine particles. The qualitative analysis of particle-bound organics is complicated by spontaneous molecular fragmentation that occurs during ionization. Research in our group is underway to devise softer, resonant ionization schemes that minimize undesired fragmentation. A long-term goal of this research is the development of aerosol mass spectrometry as a real-time, field-ready, qualitative and quantitative monitor for common organic pollutants like PAHs.

Selected Publications

Hunt, A. L.; Petrucci, G. A. "Analysis of Ultrafine and Organic Particles by Aerosol Mass Spectrometry," Trends Analyt. Chem. 2002, 21, 74.

Petrucci, G. A.; Farnsworth, P. B.; Cavalli, P.; Omenetto, N. "Differentially Pumped Particle Inlet for Sampling of Atmospheric Aerosols into a Time-of-Flight Mass Spectrometer: Optical Characterization of the Particle Beam," Aerosol Sci. Tech. 2000, 33, 105.

Nunez-Hidalgo, M.; Cavalli, P.; Petrucci, G. A.; Omenetto, N. "Analysis of Sulphuric Acid Aerosols by Laser-Induced Breakdown Spectroscopy and Laser-Induced Photofragmentation," Appl. Spectroscopy 2000, 54, 1805.

Omenetto, O.; Cavalli, P.; Hidalgo, M.; Petrucci, G. A. "Laser-Induced Photofragmentation and Fluorescence Spectroscopy: Tools for Studying Atmospheric Chemical Reactions and Aerosols," Annali di Chimica 1997, 87, 241.

Petrucci, G. A.; Cavalli, P.; Omenetto, O. "A Feasibility Study of the Use of Electrostatic Deposition and Laser-Induced Fluorescence in a Graphite Furnace for Size-Segregated Analysis of Lead and Gold in Ultrafine (0.02-0.2 μm) Particles," Spectrochimica Acta B 1997, 52, 1597.