AgNPs functionalized with dithizone for the detection of Hg2+ based on surface–enhanced Raman scattering spectroscopy

Mercuric ion (Hg2+), a poisonous metal ion that remained in water ecosystems, can severely damage the human central and peripheral nervous system and kidneys. Consequently, rapid and highly sensitive methods to determine trace Hg2+ are meaningful to discuss. We have proposed a novel approach of surface-enhanced Raman scattering (SERS) for the quantitative analysis of Hg2+ in water samples using dithizone (DTZ) as a Raman reporter. DTZ-modified silver nanoparticles (AgNPs) produced a strong SERS signal. In the presence of Hg2+, the DTZ can capture Hg2+ composing a stable structure, resulting in DTZ leaving the surface of the AgNPs, with an accompanying decrease in the signal. The proposed SERS assay showed a linear range of 10−4–10−8 M, with a limit of detection of 9.83 × 10−9 M. The sensor has low detection cost, rapid detection speed, and uncomplicated sample pretreatment. Furthermore, this method can be successfully utilized to detect Hg2+rapidly in water samples, which sheds new light on the detection of Hg2+ in the environment.

LC-MS/MS Method for Determination of Hydroxychloroquine and Metabolites: Application in a Pharmacokinetic Study

Hydroxychloroquine (HCQ) was originally used as an antimalarial and immunomodulation drug. We developed and validated a simple and sensitive ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for simultaneous quantitation of HCQ and its three metabolites in rat blood, and reported their pharmacokinetic parameters. The chromatographic separation and detection of analytes were achieved within 4 min on ZORBAX SB-C8 (3.5 μm, 2.1 × 150 mm) column with gradient elution, and the flow rate was 0.25 mL/min. Simple protein precipitation was successfully applied for sample pretreatment. The HCQ displays a good linearity in the range of 2.0–5000.0 ng/mL, and the three metabolites also show good linearity ranging from 1.0 to 2500.0 ng/mL, with all correlation coefficients (R2) better than 0.98. In conclusion, this rapid, sensitive method was successfully developed, validated, and then applied to a pharmacokinetic study of HCQ in rat model in high dose. The results of the pharmacokinetic study presented an average half-life time 21.14 ± 10.31 h (mean ± SD) of HCQ, which is much shorter in human compared to that in mice. For the three metabolites, longer half-life times (approximately 100 h) were shown in rat.

Evaluation of a Porous Imine-Based Covalent Organic Framework for Solid-Phase Extraction of Nitroimidazoles

Covalent organic framework materials (COFs), a kind of porous organic material, have excellent potential application in the field of sample pretreatment due to their high surface areas and thermal stability....

Bottom-up/cross-linking mass spectrometry via simplified sample processing on anion-exchange solid-phase extraction spin column

Capturing proteins on anion-exchange discs facilitates concentration of diluted samples and removal of contaminants, allowing more efficient sample pretreatment for bottom-up/cross-linking mass spectrometry than in-solution and in-gel.

A Rapid Method for Postmortem Vitreous Chemistry—Deadside Analysis

Vitreous fluid is commonly collected for toxicological analysis during forensic postmortem investigations. Vitreous fluid is also often analyzed for potassium, sodium, chloride and glucose for estimation of time since death, and for the evaluation of electrolyte imbalances and hyperglycemia, respectively. Obtaining such results in the early phase of a death investigation is desirable both in regard to assisting the police and in the decision-making prior to the autopsy. We analyzed vitreous fluid with blood gas instruments to evaluate/examine the possible impact of different sampling and pre-analytical treatment. We found that samples from the right and left eye, the center of the eye as well as whole vitreous samples gave similar results. We also found imprecision to be very low and that centrifugation and dilution were not necessary when analyzing vitreous samples with blood gas instruments. Similar results were obtained when analyzing the same samples with a regular multi-analysis instrument, but we found that such instruments could require dilution of samples with high viscosity, and that such dilution might impact measurement accuracy. In conclusion, using a blood gas instrument, the analysis of postmortem vitreous fluid for electrolytes and glucose without sample pretreatment produces rapid and reliable results.