This study investigated the significant influence of HCO3 – on the degradation of contaminants of emerging concern (CECs) during nitrate photolysis at 254 nm for water reuse applications. The second-order rate constants for the reactions between selected contaminants with carbonate radical (CO3 •–) were determined at pH 8.8 and T = 20 °C: estrone ((5.3 ± 1.1) × 108 M–1 s–1), bisphenol A ((2.8 ± 0.2) × 108 M–1 s–1), 17α-ethynylestradiol ((1.6 ± 0.3) × 108 M–1 s–1), triclosan ((4.2 ± 1.4) × 107 M–1 s–1), diclofenac ((2.7 ± 0.7) × 107 M–1 s–1), atrazine ((5.7 ± 0.1) × 106 M–1 s–1), carbamazepine ((4.2 ± 0.01) × 106 M–1 s–1), and ibuprofen ((1.2 ± 1.1) × 106 M–1 s–1). Contributions from UV, reactive nitrogen species (RNS), hydroxyl radical (•OH), and CO3 •– to the CEC decomposition in UV/NO3 – in the presence and absence of HCO3 – were investigated. In addition, possible transformation products and degradation pathways of triclosan, diclofenac, bisphenol A, and estrone in UV/NO3 –/HCO3 – were proposed based on the mass (MS) and MS2 spectra. Significant reduction in the cytotoxicity of bisphenol A was observed after the treatment with UV/NO3 –/HCO3 –.

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The forensic analysis of textile fibers uses a variety of techniques from microscopy to spectroscopy. One such technique that is often used to identify the dye(s) within the fiber is mass spectrometry (MS). In the traditional MS method, the dye must be extracted from the fabric and the dye components are separated by chromatography prior to mass spectrometric analysis. Direct analysis of the dye from the fabric allows the omission of the lengthy sample preparation involved in extraction, thereby significantly reducing the overall analysis time. Herein, a direct analysis of dyed textile fabric was performed using the infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) source for MS. In MALDESI, an IR laser with wavelength tuned to 2.94 μm is used to desorb the dye from the fabric sample with the aid of water as the matrix. The desorbed dye molecules are then post-ionized by electrospray ionization (ESI). A variety of dye classes were analyzed from various fabrics with little to no sample preparation allowing for the identification of the dye mass and in some cases the fiber polymer. Those dyes that were not detected using MALDESI were also not observed by direct infusion ESI of the dye standard.

Advanced oxidation using UV and hydrogen peroxide (UV/H 2 O 2) has been widely applied to degrade contaminants of emerging concern (CECs) in wastewater for water reuse. This study investigated the degradation kinetics of mixed CECs by UV/H 2 O 2 under variable H 2 O 2 doses, including bisphenol A, estrone, diclofenac, ibuprofen, and triclosan. Reverse osmosis (RO) treated water samples from Orange County Water District's Groundwater Replenishment System (GWRS) potable reuse project were collected on different dates and utilized as reaction matrices with spiked additions of chemicals (CECs and H 2 O 2) to assess the application of UV/H 2 O 2. Possible degradation pathways of selected CECs were proposed based on high resolution mass spectrometry identification of transformation products (TPs). Toxicity assessments included cytotoxicity, aryl hydrocarbon receptor-binding activity, and estrogen receptor-binding activity, in order to evaluate potential environmental impacts resulting from CEC degradation by UV/H 2 O 2. Cytotoxicity and estrogenic activity were significantly reduced during the degradation of mixed CECs in Milli-Q water by UV/H 2 O 2 with high UV fluence (3200 mJ cm À2). However, in GWRS RO-treated water samples collected in April 2017, the cytotoxicity and estrogen activity of spiked CEC-mixture after UV/H 2 O 2 treatment were not significantly eliminated; this might be due to the high concentration of target CEC and their TPs, which was possibly affected by the varied quality of the secondary treatment influent at this facility such as sewer-shed and wastewater discharges. This study aimed to provide insight on the impacts of post-UV/H 2 O 2 CECs and TPs on human and ecological health at cellular level.

Trace evidence is a significant portion of forensic cases. Textile fibers are a common form of trace evidence that are gaining importance in criminal cases. Currently, qualitative techniques that do not yield structural information are primarily used for fiber analysis, but mass spectrometry is gaining an increasing role in this field. Mass spectrometry yields more quantitative structural information about the dye and polymer that can be used for more conclusive comparisons. Matrix-assisted laser desorption electrospray ionization (MALDESI) is a hybrid ambient ionization source being investigated for use in mass spectrometric fiber analysis. In this manuscript, IR-MALDESI was used as a source for mass spectrometry imaging (MSI) of a dyed nylon fiber cluster and single fiber. Information about the fiber polymer as well as the dye were obtained from a single fiber which was on the order of 10 μm in diameter. These experiments were performed directly from the surface of a tape lift of the fiber with a background of extraneous fibers.