Speciation of Tin in Tobacco by High-Performance Liquid Chromatography – Inductively Coupled Plasma – Mass Spectrometry (HPLC-ICP-MS)

Insight into the mechanism and toxicology of nitrofurantoin: a metabolomics approach

Safety and effectiveness are the two ends of the balance in drug development that needs to be evaluated. The biotransformation of drugs within a living organism could potentiate biochemical insults in the tissue and compromise the safety of drugs. Nitrofurantoin (NFT) is a cheap clinical antibiotic with a wide array of activities against gram-positive and gram-negative organisms. The NFT scaffold has been utilized to develop other derivates or analogues in the quest to repurpose drugs against other infectious diseases. Several techniques were developed over the years to study the mechanism of NFT metabolism and toxicity, such as voltammetry, chromatographic analysis, protein precipitation, liquid-liquid extraction, etc. Due to limitations in these methods, the mechanism of NFT biotransformation in the cell is poorly understood. Metabolomics has been adopted in drug metabolism to understand the mechanism of drug toxicity and could provide a solution to overcome the limitations of current techniques to determine mechanisms of toxicity. Unfortunately, little or no information regarding the metabolomics approach in NFT metabolism and toxicity is available. Hence, this review highlights the metabolomic techniques that can be adopted in NFT metabolism and toxicological studies to encourage the research community to widely adopt and utilize metabolomics in understanding NFT's metabolism and toxicity.

Development of UV-Vis spectroscopy-based analysis method for determination of tin(IV) in epilobium parviflorum (hoary willowherb) tea using deep eutectic solvent based preconcentration

In this study, a UV-Vis Spectroscopy-based method was developed for the determination of tin(IV) in epilobium parviflorum tea samples after preconcentration. The preconcentration process was carried out using the liquid-liquid microextraction technique. Before starting the analysis, optimization studies were carried out for the variables likely to affect the experimental results. As a result of the analyzes performed under optimum conditions, the detection limit of our method was calculated as 16.83 μg/L. The percent relative standard deviation value was calculated as 1.25% (n = 8) and linearity was found in the range of 10-1000 μg/L. Recovery experiments were performed on epilobium parviflorum tea samples using the matrix matching method. As a result of the analyzes made on teas belonging to three different brands, recovery results ranging from 92 to 117% were obtained.

Simultaneous quantification of tin and lead species in Antarctic krill and fish by interfacing high-performance liquid chromatography with inductively coupled plasma mass spectrometry based on strong cation-exchange and Amphion columns

Tin and lead are a global concern considering their species-dependent toxicity, bioavailability and transformation. Simultaneous speciation analysis of tin and lead is challenging for a large food capacity containing unstable species. Herein, we developed two sensitive methods for rapid quantification of tin and lead species in Antarctic seafood by high-performance liquid chromatography and inductively coupled plasma mass spectrometry based on strong cation-exchange and Amphion columns. Inorganic tin and lead, four organotin and two organolead compounds can be analysed in 16 min on a 10-cm Amphion II column (mobile phase: 4 mM sodium dodecyl benzene sulfonate at pH 2.0) with 0.02-0.24 μg L-1 detection limits. The method was applied to Antarctic krill and fish, demonstrating the presence of any tin and lead species down to μg kg-1 level. Overall, the proposed methods are sensitive, efficient and environment-friendly for routine speciation analysis of tin and lead in food samples.

Occupational exposure to organotin substances: Development of a liquid chromatographic separation method for 11 organotin compounds in workplace air samples via HPLC-ICP-MS

Organotin compounds (OTCs) are widely regulated but rank among the most used organometallic compounds in various industrial sectors. They are significantly more toxic than inorganic tin compounds. At workplaces, OTCs can be released as vapors or dust particles and can be absorbed by inhalation or skin contact. Occupational exposure thus represents a great risk for the absorption of OTCs for employees. Methods for OTCs speciation in workplace air monitoring currently do not exist. This study describes the development of a separation method for eleven in Germany regulated OTCs via HPLC-ICP-MS. The method allows a near baseline separation of MMT, MBT, MOT, MPhT, DMT, DBT, DPhT, TMT, TBT, TPhT and TTMT within 22 min on a C18 column and a ternary solvent and flow rate gradient using methanol, acetonitrile, and ultrapure water + 6% (v/v) acetic acid + 0.17% (m/v) α-tropolone. Ten analytes show linearity in the working range of 10 - 100 µg OTCs/L with R² > 0.999. Due to its high volatility the analyte TTMT showed a quadratic relationship between concentration and signal intensity with R² = 0.9998. The determination of the instrumental limits resulted in detection limits between 0.14 and 0.57 µg Sn/L and limits of quantification between 0.49 and 1.97 µg Sn/L. Over the course of this study thermal instability and cross reactivity of OTC in solution became apparent. Formation of two reaction products in mixed OTCs solutions have been observed. These effects will further be examined within development of appropriate sampling and sample preparation for workplace air to provide a suitable method for the determination of OTCs at workplaces according to normative references.

Fabrication of a honeycomb-like bimetallic SERS substrate for the detection of triphenyltin chloride

Triphenyltin chloride (TPhT) is an organotin compound that causes intensive toxicological risk to the environment and humans. A detection method with high sensitivity and stability is therefore desired to better detect TPhT. In this study, a novel SERS substrate was prepared by sputtering an ultra-thin Au layer on a honeycomb-like silver nanoarray fabricated via the nanosphere lithography method. The ultra-thin Au layer was formed by sputtering the intermittent Au nanoparticles on the silver nanoarray, resulting in bimetallic coupling with dramatically increased hotspots and extremely high SERS enhancement with an analytical enhancement factor (AEF) of 6.08 × 10⁹ using Rhodamine 6G (R6G) as the probe molecule. Based on density functional theory (DFT) simulations, the Raman characteristic peaks of TPhT at 999 cm^-1 and 655 cm^-1 were selected for TPhT detection. The AEF of the SERS substrate HC5-AgAu was calculated to be 3.38 × 10⁶ with the detection concentration of TPhT down to 10^-10 M. The as-prepared honeycomb-like silver-gold bimetallic SERS substrate demonstrated great stability and sensitivity for TPhT detection, which might also be applied in monitoring many other environmental pollutants.

Recent Advances in Speciation Analyses of Tobacco and Other Important Economic Crops

Background:

Speciation analysis is defined as the analytical activities of identifying and/or measuring the quantities of one or more individual chemical species in a sample. The knowledge of elemental species provides more complete information about mobility, bioavailability and the impact of elements on ecological systems or biological organisms. It is no longer sufficient to quantitate the total elemental content of samples to define toxicity or essentiality. Thus speciation analysis is of vital importance and generally offers a better understanding of a specific element.

Discussion:

Thorough speciation scheme consisting of sampling, sample preparation, species analysis and evaluation were described. Special emphasis is placed on recent speciation analysis approaches including both direct and coupling methods. A current summary of advantages and limitations of the various methods as well as an illustrative method comparison are presented. Certain elements and species of interest are briefly mentioned and practical examples of speciation applications in tobacco and other important economic crops are also discussed.

Aim/Conclusion:

This review aims to offer comprehensive knowledge about elemental speciation and provide readers with valuable information. Many strategies have been developed for the determination of multiple elemental species in tobacco and other important economic crops. Nevertheless, it is an eternal pursuit to establish speciation methods which can balance accuracy, agility as well as universality.