Integrated Sensing and Processing Acoustic Resonance Spectrometry (ISP-ARS) for Sample Classification

Abstract

This research introduces a novel process analytical technique, integrated sensing and processing acoustic resonance spectrometry (ISP-ARS), and compares ISP-ARS with conventional full-spectrum ARS for the characterization of solid fuel premixes used in a new pill safe designed to protect narcotics. In ISP-ARS, the acoustic excitation waveform is the analog implementation of the chemometric weight function, encoded for this work on an MP3 player and used to distinguish between fuel samples, sparing post-collection multivariate computation. In effect, the detector directly outputs the sample identity. Repeated measurements of batches of similar fuel mixtures over time produce an automatic projection of similar spectra into corresponding three-dimensional probability density contours, thus, forming the analyte classification directly. For the characterization of ten different fuel mixtures, full spectral ARS resulted in a median intermixture distance in multidimensional standard deviations (MSDs) of 185.1, while ISP-ARS resulted in a median MSD distance of 81.3. The median cross-validation MSD was 1.41 for the ARS and 1.58 for the ISP-ARS. Distances in MSDs greater than three are considered separable, and MSDs less than three are indistinguishable. The classification procedure correctly identified all samples for both analytical techniques. ISP-ARS is an effective, simpler, and more rapid alternative to full spectrum ARS that can be implemented with a commercial MP3 player and used as an inexpensive spectrometric sensor for dynamic data-driven application simulations (DDDAS) and process analytical applications.

Integrated Sensing and Processing—Acoustic Resonance Spectrometry (ISP-ARS) in Differentiating d-Tagatose and Other Toll Manufactured Drugs

“…Additional scans of the same type of tablets contained the information needed to draw probability density contour plots encompassing the regions where spectral points of more samples of the same material were likely to be found. This approach of digitally calculating PCs initially to form an excitation waveform (effectively an analog computing alternative to the more typical digital analysis after spectra have been collected) allows for a rapid data acquisition and determination of probability densities for classification [26]. Figure 4 illustrates the cluster patterns using conventional ARS with principal component (PC) analysis.…”

“…FTARS is well established and has been shown to differentiate drugs [12][13][14][15], powders [16][17][18], liquids [16,[19][20][21], as well as predict dissolution rate in otherwise identical samples [13]. FTARS is non-destructive and complete scans can be made in seconds; therefore, it is a prime candidate for use as a process analytical technique (PAT).…”

Exploiting statistical energy test for comparison of multiple groups in morphometric and chemometric data

“…In chemometrics, parametric MANOVA was applied to identify key frequencies in integrated sensing and processing acoustic resonance spectrometry by Medendorp et al [31]. PLS analysis was advised by Ståhle and Wold [32] as an alternative to parametric MANOVA, if the assumptions of MANOVA are not fulfilled.…”

In-line ultrasound measurement system for detecting tablet integrity

“…In ARS, the acoustic signal is guided to the surface of a tablet, where the acoustic wave interacts with the tablet, and this interaction can be differentiated between tablets of similar size and shape (Medendorp and Lodder, 2006;Medendorp et al, 2007). ARS might be possible to use as an online measurement technique but it is slow because one measurement takes seconds in time (Medendorp et al, 2007).…”