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Malondialdehyde (MDA), a mutagenic and carcinogenic compound, is widely studied in the meat industry and lipid peroxidation research due to its implications for food quality and safety. Current methods for quantifying MDA in solid tissues are labor-intensive, requiring multiple instruments and approximately two hours to complete. This study presents an ultrafast kinetic fluorogenic method for quantifying MDA in ground beef, utilizing 2-thiobarbituric acid (TBA) as a fluorogenic probe. The total assay time is significantly shortened to 6 min from sample preparation to data acquisition. The assay’s robustness against matrix interference was validated using sample volume variation and standard addition calibration methods. Additionally, the effects of ambient exposure to air, washing, and cooking on MDA content in raw ground beef were quantified. While both ambient exposure to air and cooking increased MDA levels, washing raw ground beef and decanting cooked ground beef broth effectively reduced MDA levels in the ground beef. This simple and rapid assay can be adopted both in food research and industry. Moreover, insights from our study on the relationship between ground beef treatment and MDA concentration will help consumers make informed decisions about ground beef handling and consumption to lower their intake of MDA. 

UV–vis spectrophotometry and spectrofluorometry are indispensable tools in education, research, and industrial process controls with widespread applications in nanoscience encompassing diverse nanomaterials and fields. Nevertheless, the prevailing spectroscopic interpretations and analyses often exhibit ambiguity and errors, particularly evident in the nanoscience literature. This analytical chemistry Perspective focuses on fostering evidence-based data interpretation in experimental studies of materials’ UV–vis absorption, scattering, and fluorescence properties. We begin by outlining common issues observed in UV–vis and fluorescence analysis. Subsequently, we provide a summary of recent advances in commercial UV–vis spectrophotometric and spectrofluorometric instruments, emphasizing their potential to enhance scientific rigor in UV–vis and fluorescence analysis. Furthermore, we propose potential avenues for future developments in spectroscopic instrumentation and measurement strategies, aiming to further augment the utility of optical spectroscopy in nano research for samples where optical complexity surpasses existing tools. Through a targeted focus on the critical issues related to UV–vis and fluorescence properties of nanomaterials, this Perspective can serve as a valuable resource for researchers, educators, and practitioners. 

Cascading optical processes involve sequential photon–matter interactions triggered by the same individual excitation photons. Parts I and II of this series explored cascading optical processes in scattering-only solutions (Part I) and solutions with light scatterers and absorbers but no emitters (Part II). The current work (Part III) focuses on the effects of cascading optical processes on spectroscopic measurements of fluorescent samples. Four types of samples were examined: (1) eosin Y (EOY), an absorber and emitter; (2) EOY mixed with plain polystyrene nanoparticles (PSNPs), which are pure scatterers; (3) EOY mixed with dyed PSNPs, which scatter and absorb light but do not emit; and (4) fluorescent PSNPs that are simultaneous light absorbers, scatterers, and emitters. Interference from both forward scattered and emitted photons can cause nonlinearity and spectral distortion in UV–vis extinction measurements. Sample absorption by nonfluorogenic chromophores reduces fluorescence intensity, while the effect of scattering on fluorophore fluorescence is complicated by several competing factors. A revised first-principles model is developed for correlating the experimental fluorescence intensity with the sample absorbance in solutions containing both scatterers and absorbers. The optical properties of fluorescent PSNPs of three different sizes were systematically investigated by using integrating-sphere-assisted resonance synchronous spectroscopy, linearly polarized resonance synchronous spectroscopy, UV–vis, and fluorescence spectroscopy. The insights and methodology provided in this work should help improve the reliability of spectroscopic analyses of fluorescent samples, where the interplay among light absorption, scattering, and emission can be complex.