Direct infrared spectroscopy for the size-independent identification and quantification of respirable particles relative mass in mine dusts
Creators: name: Stach, Robert
name: Barone, Theresa
name: Cauda, Emanuele
name: Krebs, Patrick
name: Pejcic, Bobby
name: Daboss, Sven
name: Mizaikoff, Boris
Publisher: name: Universität Ulm
Year: 2020
Subjects: subject: IR
subject: FTIR
subject: Diffuse reflectance
subject: DRIFTS
subject: Inhalable particles
subject: Crystalline silica
subject: Occupational safety
subject: Mining
subject: Multivariate data analysis
subject: Partial least squares regression
subject: PLSR
subject: DDC 540 / Chemistry &amp; allied sciences
subject: Infrared spectroscopy
subject: Fourier transform infrared spectroscopy
subject: Mineral dusts
subject: Chemometrics
subject: FT-IR-Spektroskopie
subject: DRIFT-Spektroskopie
subject: Quarz; alpha
subject: Faserstaub
subject: Chemometrie
subject: Methode der partiellen kleinsten Quadrate

description: Due to the global need for energy and resources, many workers are involved in underground and surface mining operations where they can be exposed to potentially hazardous crystalline dust particles. Besides commonly known alpha quartz, a variety of other materials may be inhaled when a worker is exposed to airborne dust. To date, the challenge of rapid in-field monitoring, identification, differentiation, and quantification of those particles has not been solved satisfactorily, in part because conventional analytical techniques require laboratory environments, complex method handling, and tedious sample preparation procedures and are in part limited by the effects of particle size. Using a set of the three most abundant minerals in limestone mine dust (i.e., calcite, dolomite, and quartz) and real-world dust samples, we demonstrate that Fourier transform infrared (FTIR) spectroscopy in combination with appropriate multivariate data analysis strategies provides a versatile tool for the identification and quantification of the mineral composition in relative complex matrices. An innovative analytical method with the potential of in-field application for quantifying the relative mass of crystalline particles in mine dust has been developed using transmission and diffuse reflection infrared Fourier transform spectroscopy (DRIFTS) within a unified multivariate model. This proof-of-principle study shows how direct on-site quantification of crystalline particles in ambient air may be accomplished based on a direct-on-filter measurement, after mine dust particles are collected directly onto PVC filters by the worker using body-mounted devices. Without any further sample preparation, these loaded filters may be analyzed via transmission infrared (IR) spectroscopy and/or DRIFTS, and the mineral content is immediately quantified via a partial least squares regression (PLSR) algorithm that enables the combining of the spectral data of both methods into a single robust model. Furthermore, it was also demonstrated that the size regime of dust particles may be classified into groups of hazardous and less hazardous size regimes. Thus, this technique may provide additional essential information for controlling air quality in surface and underground mining operations.