A new portable micropipette tip-syringe based solid phase microextraction for the determination of vanadium species in water and food samples

A modified selective optical sensor for selenium determination based on incorporating xylenol orange in a poly(vinyl chloride) membrane

A novel optical sensor has been developed to measure selenium ions. The sensor membrane was created by mixing xylenol orange (XO) and sodium tetraphenylborate (NaTPB) with a plasticized poly(vinyl chloride) membrane that contained o-nitrophenyl octyl ether (o-NPOE) as a plasticizer. XO was previously established for use in a colorimeter to measure selenium in water and other media. At pH 6.6, the color of the detecting membrane changed from orange to pink when in contact with Se4+ ions. Various variables affecting the uptake efficiency were evaluated and optimized. Under optimum conditions (i.e., 30% PVC, 60% o-NPOE, and 5.0% of both XO and NaTPB for 5.0 min as the response time), the proposed sensor displayed a linear range 10-175 ng mL-1 with the detection and quantification limits of 3.0 and 10 ng mL-1, respectively. Also, the precision (RSD%) was better than 2.2% for six replicate determinations of 100 ng mL-1 Se4+ in various membranes. For the detection of Se4+, the selectivity of the sensor membrane was investigated for a number of possible interfering inorganic cations, but no appreciable interference was found. With the use of a 0.3 M HCl solution, the sensor was successfully restored, and the response that may have been reversible and reproducible exhibited an RSD% of less than 2.0%. The sensor has been successfully used to analyze Se4+ ions in environmental and biological materials.

A New Trend and Future Perspectives of the Miniaturization of Conventional Extraction Methods for Elemental Analysis in Different Real Samples: A Review

Sample preparation is one of the viable procedures to be used before analysis to enhance sensitivity and reduce the matrix effect. The current review is mainly emphasized the latest outcome and applications of microextraction techniques based on the miniaturization of the classical conventional methods based on liquid-phase and solid-phase extraction for the quantitative elemental analysis in different real samples. The limitation of the conventional sample preparation methods (liquid and solid phase extraction) has been overcome by developing a new way of reducing size as compared with the conventional system through the miniaturization approach. Miniaturization of the sample preparation techniques has received extensive attention due to its extraction at microlevels, speedy, economical, eco-friendly, and high extraction capability. The growing demand for speedy, economically feasible, and environmentally sound analytical approaches is the main intention to upgrade the conventional procedures apply for sample preparation in environmental investigation. A growing trend of research has been perceived to quantify the trace for elemental analysis in different natures of real samples. This review also recapitulates the current futuristic scenarios for the green and economically viable procedure with special overemphasis and concentrates on eco-friendly miniaturized sample-preparation techniques such as liquid-phase microextraction (LPME) and solid-phase microextraction (SPME). This review also emphasizes the latest progress and applications of the LPME and SPME approach and their future perspective.

PCR-tips for rapid diagnosis of bacterial pathogens

Micropipette tips are currently among the most used disposable devices in bioresearch and development laboratories. Their main application is the fractionation of solutions. New functionalities have recently been added to this device, widening their applications. This paper analyzed disposable micropipette tips as reagent holders of PCR reagents. PCR has become a prevalent and often indispensable technique in biological laboratories for various applications, such as the detection of coronavirus and other infectious diseases. A functional micropipette tip was implemented to simplify PCR analysis and reduce the contamination chances of deoxynucleotides and specific primers. This disposable device is prepared by tip coating processes of reagents, using polyvinyl alcohol polymer and additives. The coated layer is optimized to load and release PCR reagents efficiently. As a proof of concept, we show that the detection of Bordetella pertussis, the etiological agent of whooping cough whose diagnostic relies on PCR, can be quickly done using practical-functional tips. This device is an excellent example of testing the functionality and contribution of molecular diagnostic PCR tips. KEY POINTS: • Functional micropipette tips are prepared by coating with dNTPs and primers. • Functional tips are used to replace dNTPs and primers in the PCR master mix. • PCR diagnostic of Bordetella pertussis is performed using functional tips.

Vanadium: A Review of Different Extraction Methods to Evaluate Bioavailability and Speciation

The excessive input of heavy metals such as vanadium (V) into the environment has been one of the consequences of global industrial development. Excessive exposure to V can pose a potential threat to ecological safety and human health. Due to the heterogeneous composition and reactivity of the various elements in soils and sediments, quantitative analysis of the chemical speciation of V in different environmental samples is very complicated. The analysis of V chemical speciation can further reveal the bioavailability of V and accurately quantify its ecotoxicity. This is essential for assessing for exposure and for controlling ecological risks of V. Although the current investigation technologies for the chemical speciation of V have grown rapidly, the lack of comprehensive comparisons and systematic analyses of these types of technologies impedes a more comprehensive understanding of ecosystem safety and human health risks. In this review, we studied the chemical and physical extraction methods for V from multiple perspectives, such as technological, principle-based, and efficiency-based, and their application to the evaluation of V bioavailability. By sorting out the advantages and disadvantages of the current technologies, the future demand for the in situ detection of trace heavy metals such as V can be met and the accuracy of heavy metal bioavailability prediction can be improved, which will be conducive to development in the fields of environmental protection policy and risk management.

Novel semi-automated graphene nanosheets based pipette-tip assisted micro-solid phase extraction as eco-friendly technique for the rapid detection of emerging environmental pollutant in waters

In this work, a new semi-automated syringe infusion-pump assisted graphene nanosheets (GNSs) based pipette-tip micro-solid phase extraction (PT-μSPE) as a green sample preparation technique was demonstrated for the sensitive analysis of emerging environmental pollutant in environmental waters using HPLC-UV. Microwave-assisted synthesized GNSs powder was packed into a 100 μL pipette-tip (as PT-μSPE cartridge) connected with a commercial plastic syringe (contains water sample). This setup was attached to a programmable auto-syringe infusion pump for the GNSs-PT-μSPE process. Triclosan (TCS) is an emerging environmental pollutant chosen as a target analyte to examine the extraction capacity and feasibility of GNSs as a sorbent material for PT-μSPE. Parameters affecting the extraction capability were systematically evaluated and thoroughly optimized. At optimized experimental parameters, excellent linearity (r² = 0.9979) was achieved over the concentration range of 2-250 ng mL^-1 for TCS, with a detection limit of 0.5 ng mL^-1. Applicability of the presented method was examined with real water samples, and extraction recoveries obtained were ranged between 94.6-102.4% with RSD less than 7.8%. The presented protocol is a simple, semi-automated, eco-friendly, low-cost, and efficient sample pretreatment technique for quick analysis of TCS in environmental wastewaters.

A global systematic review, meta-analysis, and risk assessment of the concentration of vanadium in drinking water resources

The presence of toxic metals such as vanadium in water resources has attracted considerable attention as a new concern in international health. Systematic review and meta-analysis were performed to assess the concentration of vanadium in water resources along with the relevant ecological risk assessment. Databases of Scopus, PubMed, and Embase were investigated to retrieve the related articles from January 01, 1974 to December 25, 2019. Twenty-eight articles containing 152 samples from 24 countries were included. Furthermore, the meta-analysis was conducted by the approach of z-score to estimate differences in the effect size. In addition, the mean of concentrations of vanadium was applied to calculate the risk assessment only to the water surface and choose the maximum environmental concentration (MEC) for demonstrate a worst-case scenario. Here, the risk assessment approach was used to show that the MEC of vanadium confirm the risk it for aquatic ecosystems, being fish (e.g., Danio rerio) our model organism due to their sensibility. According to findings, the MEC of vanadium in surface water varied from 0.010 μg L^-1 (USA) and 68 μg L^-1 (China), with an overall mean of 6.21 ± 13.3 μg L^-1 (mean ± standard deviation). The ecological risk assessment demonstrated that people living in some countries such as China and Japan were at an adverse ecological risk of vanadium in the water resources. Hence, essential control plans besides adequate removal techniques must be implemented for significant deracination of heavy metals like vanadium.

Pipette-tip micro-solid phase extraction based on melamine-foam@polydopamine followed by ultra-high-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry for detection of psychotropic drugs in human serum

In this work, pipette-tip micro-solid phase extraction (PT-μSPE) which packed by melamine-foam@polydopamine (MF@PDA) coupled with ultra-high-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UHPLC-QTOF) was developed for extraction and determination of psychotropic drugs in serum samples. Considering the operation back pressure, the melamine-foam as carrier material with 3D cross-linked grid structure can provide high permeability and contact surface. MF@PDA was prepared by self-polymerization reaction of dopamine under weak alkaline conditions and characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). The surface group of PDA containing catechol structure, quinone structure and amine group has multi-interaction with psychotropic drugs which can increase the adsorption capacity. Moreover, the parameters affecting extraction efficiencies such as extraction and desorption cycle, pH value, eluent type, ionic strength and amount of sorbent were investigated. Based on the high sensitivity and accuracy mass measurement by TOF/MS, under the optimized extraction condition, the limits of detection (LOD) of this method were obtained in the range of 0.002-0.1 ng ml^-1. The linearity was ranged from 0.01 ng ml^-1 to 600 ng ml^-1, and all the correlation coefficients (R²) were above 0.993. The spiked recoveries were in the range of 80.04% to 109.18% in real sample test and RSD values obtained from 0.95% to 9.85%. The results demonstrate that MF@PDA-PT-μSPE-UHPLC-QTOF is a sample and reliable method for the detection of psychotropic drugs in serum sample.

Review: Microextraction Technique Based New Trends in Food Analysis

Food chemistry is the study and classification of the quality and origin of foods. The identification of definite biomarkers and the determination of residue contaminants such as toxins, pesticides, metals, human and veterinary drugs, which are a very common source of food-borne diseases. The food analysis is continuously demanding the improvement of more robust, sensitive, highly efficient, and economically beneficial analytical approaches to promise the traceability, safety, and quality of foods in the acquiescence with the consumers and legislation demands. The traditional methods have been used at the starting of the 20th century based on wet chemical methods. Now it existing the powerful analytical techniques used in food analysis and safety. This development has led to substantial enhancements in the analytical accuracy, precision, sensitivity, selectivity, thereby mounting the applied range of food applications. In the present decade, microextraction (micro-scale extraction) pays more attention due to its futures such as low consumption of solvent and sample, throughput analysis easy to operate, greener, robotics, and miniaturization, different adsorbents have been used in the microextraction process with unique nature recognized with wide range applications.

Nanomaterials in speciation analysis of metals and metalloids

Nanomaterials have draw extensive attention from the scientists in recent years mainly due to their unique and attractive thermal, mechanical and electronic properties, as well as high surface to volume ratio and the possibility for surface functionalization. Whereas mono functional nanomaterials providing a single function, the preparation of core/shell nanoparticles allows different properties to be combined in one material. Their properties have been extensively exploited in different extraction techniques to improve the efficiency of separation and preconcentration, analytical selectivity and method reliability. The aim of this paper is to provide an updated revision of the most important features and application of nanomaterials (metallic, silica, polymeric and carbon-based) for solid phase extraction and microextraction techniques in speciation analysis of some metals and metalloids (As, Cr, Sb, Se). Emphasis will be placed on the presentation of the most representative works published in the last five years (2015-2019).

A ligand-anchored optical composite material for efficient vanadium(ii) adsorption and detection in wastewater

A ligand-anchored composite material was prepared for vanadium (V(ii)) ion capturing. The pH was found to be a key factor in both detection and removal operations. The composite material exhibited the high adsorption capacity of 492.61 mg g⁻¹.

Metal–organic framework based micro solid phase extraction coupled with supramolecular solvent microextraction to determine copper in water and food samples

D-μ-SPE-SUPRAS-ME followed by GFAAS was successfully used for preconcentration and determination of copper in real samples.