Conventional electrochemical sensors use voltammetric and amperometric methods with external power supply and modulation systems, which hinder the flexibility and application of the sensors. To avoid the use of an external power system and to minimize the number of electrochemical cell components, a self-powered electrochemical sensor (SPES) for hydrogen peroxide was investigated here. Iron phthalocyanine, an enzyme mimetic material, and Ni were used as a cathode catalyst and an anode material, respectively. The properties of the iron phthalocyanine catalyst modified by graphene nanoplatelets (GNPs) were investigated. Open circuit potential tests demonstrated the feasibility of this system. The GNP-modulated interface helped to solve the problems of aggregation and poor conductivity of iron phthalocyanine and allowed for the achievement of the best analytical characteristics of the self-powered H2O2 sensor with a low detection limit of 0.6 µM and significantly higher sensitivity of 0.198 A/(M·cm2) due to the enhanced electrochemical properties. The SPES demonstrated the best performance at pH 3.0 compared to pH 7.4 and 12.0. The sensor characteristics under the control of external variable load resistances are discussed and the cell showed the highest power density of 65.9 μW/cm2 with a 20 kOhm resistor. The practical applicability of this method was verified by the determination of H2O2 in blood serum.

A nondestructive and simple method for the determination of bromine and iodine in soil was investigated using an energy-dispersive X-ray fluorescence spectrometer equipped with three-dimensional polarized optics. Using a gadolinium X-ray tube and Mo and Al2O3 as optimal secondary target materials, K-lines were detected for bromine and iodine. The minimum detection limits for bromine and iodine were calculated using JSAC0411, a certified reference material of soil for metal composition analysis, and were 0.77 mg/kg for bromine and 2.3 mg/kg for iodine at a measurement time of 600 s. The results of the determination of bromine and iodine in soil samples by the standard addition method were 256 ± 8 mg/kg for iodine and 67.9 ± 1.3 mg/kg for bromine with JSAC0411, which were in close agreement with the results measured by inductively coupled plasma mass spectrometry (ICP-MS) after alkaline extraction with tetramethylammonium hydroxide (TMAH) solution. The method developed in this study is an excellent technique for direct analysis of soil by X-ray fluorescence analysis without any pretreatment such as alkaline extraction. It is expected to be a practical analytical method for elucidating the dynamics of bromine and iodine in agricultural land and soil.

With recent evolution of cannabis legalization around the world, cannabis edibles are booming, and determining their concentration in Δ9-tetrahydrocannabinol (Δ9-THC), the regulated psychoactive substance, remains a challenge for toxicology laboratories, which must prove whether the product has legal status or not. Cannabinoids are a large family of structurally similar and lipophilic molecules, requiring dedicated pre-analytical methods, as well as efficient chromatographic separation to differentiate cannabinoid isomers which are distinguished by their psychoactive properties and their legal status. Here, we present two independent cases of cannabis edibles, for which we performed analysis of homemade cannabis chocolate cakes and of the resins and herbs used for cooking. Quantitation was carried out with a new developed standard addition method, to avoid matrix effects and matrix-dependent calibration. Extraction by QuEChERs method, followed by targeted and non-targeted analysis by ultra-high performance liquid chromatography hyphenated to high resolution mass spectrometry (UHPLC-HRMS) allowed the identification of several phytocannabinoids, mainly Δ9-tetrahydrocannabinol (Δ9-THC), cannabidiol (CBD) and their acid precursors Δ9-THC acid (THCA) and CBD acid (CBDA). Δ9-THC was identified in significant concentrations (mg/g) in both edibles, even though one was prepared with CBD herb. This work highlights the need to analyze cannabis edibles, as well as the resins and herbs used in their preparation if it is homemade, and it proposes a reliable analytical method for toxicology laboratories.

Risperidone (RIS) is an atypical antipsychotic agent and its 9-hydroxylated metabolite named paliperidone (PAL) also has pharmacological properties similar to that of RIS. Quantifications of RIS and PAL in authentic human biological fluids and solid tissues by liquid chromatography (LC)-tandem mass spectrometry (MS/MS) have not been reported yet although those in plasma (and blood) were reported abundantly. In the present work, a quantification method for RIS and PAL based on the standard addition method was devised and validated for the human fluid and solid tissue specimens. RIS and PAL in biological fluids were quantified only after their dilution and deproteinization. The concentrations of RIS and PAL in the heart whole blood, pericardial fluid, stomach contents, bile, urine, liver, kidney and cerebrum were determined for a deceased who had been treated with RIS therapeutically, and also a deceased who had ingested RIS with other drugs intentionally. To our knowledge, this is the first report on the quantification of RIS and PAL by LC-MS/MS in the authentic human tissues and biological fluids.

In recent years, significant progress has been made in the development of fluorescent contrast agents for clinical applications. For the development of a fluorescent probe, it is crucial to evaluate its safety profile, including biodistribution. Specific methods need to be developed for the absolute quantification of fluorescent probes in tissue specimens from animals administered with test compounds in the framework of biodistribution/efficacy/toxicity studies. Here, we describe a new method for the absolute quantification of fluorescent probes in tissue specimens from animals administered with compounds that have absorption and emission wavelength in the Near-Infrared region (600-800 nm). The protocol is based on the standard addition approach in order to minimize the interference of the matrix on the analyte signal causing inaccuracy in the absolute determination of the concentration. The measurement of the fluorescence intensity is done via a microplate reader. The method has been fully validated and applied for the quantification of a fluorescence-guided surgery targeted contrast agent in a Good Laboratory Practice (GLP) biodistribution study. Results clearly demonstrate that this procedure is fully applicable in a preclinical setting and that it overcomes common issues associated with fluorescence signal quantification in tissue extracts.

The Savannah River Site stores approximately 36 million gallons of radioactive and hazardous waste that contains approximately 245 million curies. The waste is sent through various chemical processes to reduce its volume and to separate various components. The facility plans to replace formic acid (a chemical used to reduce soluble mercury) with glycolic acid. Recycle solution with glycolate may flow back to the tank farm, where the glycolate can generate hydrogen gas by thermal and radiolytic mechanisms. The current analytical method for detecting glycolate (ion chromatography) in supernatant requires a large dilution to reduce interference from the nitrate anions. Hydrogen nuclear magnetic resonance is an analytical method that requires less sample dilution. It takes advantage of the CH2 group in glycolate. Liquid samples were spiked with four different levels of glycolate to build a calibration line, as it is recommended in the standard addition method. The detection and quantitation limits determined were 1 and 5 ppm, respectively, for 32 scans, which is well below the process limit of 10 ppm. In one test, 800 scans of a supernatant spiked with 1 ppm glycolate resulted in a -CH2 peak with a signal-to-noise ratio of 36.

The commercial significance of accurate and simple quantification of 2-Acetyl-1-pyrroline (2-AP) cannot be overstated. Present study was carried out to standardize a method for extraction and accurate quantitation of 2-AP from rice grain using GC-MS/MS equipped with HS-SPME auto sampler. The effect of sample quantity, addition of solvent, grinding process, sample particle size, head space parameters and SPME fiber incubation parameters, were optimized in the developed method. Dehusked rice powder (2 g) prepared under liquid nitrogen, and passed through the 80-mesh sieve, incubated for 40 min at 80 °C in headspace, followed by fiber (DVB/Carbon WR/PDMS) saturation time of 15 min, could produce the maximum response. The recovery of 2-AP from fortified sample ranged between 7.02 and 9.02% at 50-200 ng g-1 fortification irrespective of the grain matrices used. Standard addition method was appropriate to overcome the matrix effect and recovery of 2-AP was more than 90% using this method. The developed method was further utilized for quantification of 2-AP in four Basmati and two non-Basmati aromatic rice samples. The content of 2-AP ranged between 57.17 and 147.10 ng g-1 of rice and varied with geographical location. This fully automated method could improve the work efficiency and reduce error during the volatile extraction and adsorption phase.
UNASSIGNED: The online version contains supplementary material available at 10.1007/s13197-023-05674-7.

Exposure to hydroquinone (HQ) can cause various health hazards and negative impacts on the environment. Therefore, we developed an efficient electrochemical sensor to detect and quantify HQ based on palladium nanoparticles deposited in a porous silicon-polypyrrole-carbon black nanocomposite (Pd@PSi-PPy-C)-fabricated glassy carbon electrode. The structural and morphological characteristics of the newly fabricated Pd@PSi-PPy-C nanocomposite were investigated utilizing FESEM, TEM, EDS, XPS, XRD, and FTIR spectroscopy. The exceptionally higher sensitivity of 3.0156 μAμM-1 cm-2 and a low limit of detection (LOD) of 0.074 μM were achieved for this innovative electrochemical HQ sensor. Applying this novel modified electrode, we could detect wide-ranging HQ (1-450 μM) in neutral pH media. This newly fabricated HQ sensor showed satisfactory outcomes during the real sample investigations. During the analytical investigation, the Pd@PSi-PPy-C/GCE sensor demonstrated excellent reproducibility, repeatability, and stability. Hence, this work can be an effective method in developing a sensitive electrochemical sensor to detect harmful phenol derivatives for the green environment.

Designer benzodiazepines (DBZDs) increasingly emerged on the novel psychoactive substance (NPS) market in the last few years. They are usually sold as readily available alternatives to prescription benzodiazepines (BZDs) or added to counterfeit medicines. BZDs are generally considered relatively safe drugs due to the low risk of serious acute adverse effects in mono-intoxication, though e.g., alprazolam seems to display an elevated risk of respiratory depression. Here we report on a fatal intoxication involving the novel DBZD flualprazolam.
A complete postmortem examination was performed. General unknown screenings and analysis of drugs of abuse were performed on postmortem samples by immunoassay, gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry. The standard addition method was employed to quantify flualprazolam in postmortem blood and tissues. Finally, a toxicological significance score (TSS) was assigned.
Flualprazolam was detected in heart serum (25.4 ng/mL) and peripheral blood (21.9 ng/mL) as well as in urine, stomach contents, brain, liver and kidney (65.2-323 ng/g). The cause of death was deemed as central nervous system (CNS) and respiratory depression with agonal aspiration of stomach contents, in the setting of a multiple drug intake. Given the concentration levels of the co-consumed CNS depressants, the contribution of flualprazolam to the death was considered likely (TSS of 3).
Our results support that highly potent DBZDs like flualprazolam carry an elevated risk for unintended toxicity, especially in association with other CNS depressants. A multidisciplinary evaluation of fatalities remains mandatory, especially when pharmacological/toxicological data on intoxicating compounds are lacking. To our knowledge this is the first report of flualprazolam concentrations in solid tissues in human.

Herein, an economical, analytical and sensitive method was established for the fluorometric determination of urea using freshly prepared silver nanoparticles (Ag-NPs) in real urine samples. The standard addition and second-order derivative methods were selected for the ongoing research work to eliminate the possible effect of interferences in a real environment. In this work, Ag-NPs were prepared by reducing silver nitrate salt in the presence of 1,3-di-(1H-imidazole-1-yl) -2-propanol (DIPO) in an aqueous medium. Urea in the urine samples was successfully determined through the complexation of Ag-NPs with urea molecules. The results revealed high percent recovery with ± RSD of urea in the three different urine samples, where percent recoveries by spectrofluorometric standard addition were 99.77 ± 3.4, 100.24 ± 5.1, 100.93 ± 2.8 and that is by the spectrofluorometric second-order derivative method were 103.57 ± 2.4, 101.8 ± 1.3, 98 ± 3.2, respectively. The successful application of these analytical methods in the spectrofluorometric determination of urea in urine samples can accumulate further addition in the effects and possible role of Ag-NPs in the determination of biological molecules in biological and non-biological samples in the scientific as well as clinical fields.