Spectroscopic characterization and comparison between biologics, organics and mineral compounds using pulsed micro-hollow glow discharge

Abstract

A new mode of operation – pulsed – is demonstrated for compound identification of solid materials in the form of dry powders. Both plasma and analytical utility are characterized spectroscopically. The acquired emission spectra provided molecular and elemental information. The microgram sample analysis capability and atmospheric pressure operation are demonstrated for benign and biological organics, a commercial fertilizer and other inorganic materials. The plasma temperature is estimated by spectral simulation of the NO (A²Σ⁺ → X²Π) bands, and the inferred temperature is 1300 °C. Atomic transitions from C (¹P⁰ → ¹S) and molecular bands from CH (B²Σ → X²Π) and CH (A²Δ → X²Π) were manifestly observed in the optical emission spectra of organic materials. Relative intensities of common spectral signatures could distinguish biological agents from common benign organic materials. High-resolution spectra were particularly useful in resolving and identifying atomic transitions such as Mg, Ca, Fe and Si for the inorganic materials. Such a detector system has the capability to rapidly sense hazards with the added advantage of portability.