Analytical and Bioanalytical Chemistry Research
Volume:10 Issue: 1, Winter 2023

Wastewater treatment is a global concern nowadays. Although there are many methods available for wastewater treatment, the adsorption method has received much more attention from researchers. Major problems for extending the adsorption method to the industry for wastewater treatment are the high cost of cosmetically available adsorbents, their recovery from the medium, and their regeneration and reuse. Magnetic biosorbents could provide easy separation from the treated water and at lower prices compared to other commercially available adsorbents. In terms of characteristics and efficiency in the adsorption of organic and inorganic pollutants, magnetic biosorbents have shown growing promise. If biosorbents and the removed pollutants are not handled and disposed of properly, they can become causes of environmental pollution. There are numerous review papers on wastewater treatment with magnetic adsorbents. However, this paper provides comprehensive information on the synthesis of magnetic nanoparticles, the magnetization of biosorbents, and the application of magnetic biosorbents for wastewater treatment to pave the avenue for new magnetic biosorbents development that can be scaled up from laboratories to the industry.

Procalcitonin (PCT), acts a significant role in the screening of bacterial infection (BI), which is one of the world’s leading health problems. This work presents a simple, efficient, and convenient glass fiber paper (GFP) substrate-based innovative biosensor applications for BI-specific PCT biomarker detection. To enhance the conductivity of the GFP substrate, a self-accumulating single layer of AuNP is used on the GFP surface. This monolayer of AuNP in GFP provides a platform for antibody immobilization and shows high electrochemical conductivity. Further, the AuNP/GFP electrode was modified with antibodies specific to PCT followed by the addition of bovine serum albumin (BSA) to block unspecific binding sites for PCT detection. The PCT/BSA/ab/AuNP/GFP bioelectrode has been successfully used to determine PCT in a serum sample with amended stability. Scanning electronic microscopy, transmission electron spectroscopy, Fourier transform infrared, UV-Vis spectroscopy, and X-ray diffraction were used to examine the structural and morphological properties. Using an electrochemical impedance response study, the developed PCT/BSA/ab/AuNP/GFP bioelectrode showed the lowest detection limit of 100 pg/ml concerning PCT detection in the linear range of 107-102 pg/ml. Electrochemical response studies show that the developed BSA/ab/AuNP/GFP bioelectrode has a lifespan of 30 days and can be used to assess PCT in the 107-102 pg/ml ranges. Moreover, this evaluated sensor offers many merits, including economical, small sample volume, single-use, and fast analysis over conventional methods, making the platform an alternative tool for PCT screening. This developed bioelectrode also shows good reproducibility in an acceptable range.

In a one-step process using low-priced materials, water-soluble mercaptoacetic acid capped cadmium sulfide quantum dots (MAA-CdS QDs) were synthesized. The mercaptoacetic acid was used as a stabilizing agent and surface modifier in the aqueous solution. The synthesis conditions were optimized to discover the effects of sodium sulfide concentration and pH values on the optical properties of cadmium sulfide quantum dots. Transmission electron microscopy (TEM), ultraviolet-visible absorption spectroscopy (UV-Vis), Fourier transform infrared (FT-IR) spectroscopy, and photoluminescence emission spectroscopy were used for studying the as-prepared quantum dots. This nanosized probe was used for selective and fast determination of cetirizine. The fluorescence emission intensity of mercaptoacetic acid capped cadmium sulfide quantum dots with excitation/emission peaks at 335/500 nm was quenched by cetirizine, effectively. The significant factors in the detection of cetirizine were examined, and the optimum conditions were recorded. Linear fluorescence intensity response of Mercaptoacetic acid capped cadmium sulfide quantum dots with cetirizine concentration is proportional in the concentration range of 1.60×10-10 to 1.16×10-9 mol L-1 under optimum conditions. The detection limit of this nanosensor was 6.48×10−11 mol L-1, and its correlation coefficient was 0.9904. In the presence of other drugs and amino acids, the fluorescence emission intensity of the MAA-CdS QDs probe was investigated to define the sensor's selectivity.

Polycyclic aromatic hydrocarbons (PAHs) have been listed among the hazardous compounds according to the US environmental protection agency (USEPA) and the world health organization (WHO). Even low concentrations of PAHs have shown serious toxicity, highlighting the necessity of the measurement of these compounds which require highly sensitive and precise methods. In this study, for the first time, a solid phase microextraction (SPME) fiber was fabricated by a highly porous monolithic nanofiber nanocomposite based on polyethersulfone (PES)/multiwalled carbon nanotubes (MWCNTs) and used for direct sampling of indoor air before identification of polycyclic aromatic compounds by gas chromatography-flame ionization detector (GC-FID). A new homemade sampling chamber was also designed to increase the exposure of airborne PAHs to the proposed SPME fiber. The microextraction conditions were optimized. The correlation coefficients and the linear range (LDR) of the compounds ranged from 0.9991 to 0.9996 and from 0.02 to 10 mg/m3, respectively. In addition, the limit of detection (LOD) varied in the range of 0.014-0.032 mg/m3. The relative standard deviation (RSD) for single fiber and fiber to fiber was 2.95 and 5.95%, respectively. This method was successfully applied to measure some PAHs in indoor spaces.

We designed a facial and novel CeO2/NiO/NiAl2O4 nanocomposite prepared by recalcination of the cerium impregnated product of the primary calcined production of NiAl-NO3 layered double hydroxide (LDH) through the structural memory effect. The materialization of as-prepared nanocomposite was confirmed by Fourier-transform infrared (FT-IR) spectroscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), thermal gravimetry (TG), dynamic light scattering (DLS) and transmission electron microscopy (TEM). Morphologic studies revealed that the size of the nanocomposite was below 100 nm. The resulting mixed metal oxide nanocomposite was employed as an efficient adsorbent for the removal of Direct Red 23 (DR23) as a model pollutant from textile wastewater. The dye removal study showed >98% efficiency for the removal of dye which revealed the superiority of material for decontamination of waste water, while the maximum adsorption capacity determined from isotherm data was 588.24 mg of dye per g of the adsorbent. In addition, the reusability was also performed up to three cycles with 89, 85 and 88% efficiency for DR23. Also, thermodynamics, isotherm and kinetic studies were investigated. Overall, we offer a facile method for synthesizing CeO2/NiO/NiAl2O4 nanocomposite, efficiently decontaminating DR23 from water with good recyclability.

An accurate, fast, easy, and novel technique was developed to determine nickel ions. A selective sensor according to Ni (II)-imprinted polymer as a novel ionophore for nickel ions has been fabricated and investigated. In this research study, a screen-printed carbon electrode system as a bare electrode was introduced using screen-printing technology. An electrophoretic deposition (EPD) method has been used to deposition of graphene oxide nanosheets onto the surface of SPE. The modified screen-printed electrode (SPE) measured the nickel ions by potentiometry with high selectivity. To properly prepare the ion-selective electrode (ISE), the nickel (II)-imprinted polymer particles disperse in 2-nitrophenyloctyl ether plasticizer, then embedded in a polyvinylchloride polymeric matrix. The ISE shows a Nernstian response for nickel ions over a dynamic concentration range (1. 0×10-4- 3. 0 ×10-7 M) with a slope of 30. 44mV per decade. The limit of detection was obtained 2. 0 ×10-7 M. The desired electrode showed good selectivity over a wide range of ions. The accuracy of the suggested electrode was investigated in spiked tap water, well water, and mineral water.

In this study, Lead(II) ion imprinted polymer particles were synthesized by preparing ternary complex of lead imprinted ion with 4-(2-pyridilazo) resorcinol (PAR) and 4-vinylpyridine (VP) and then copolimerizing with methacrylic acid as functional monomer, Trimethylolpropane trimethacrylate (TRIM) as crosslinking agent, methanol as porogen, and benzoyl peroxide (BPO) as initiator. Polimerization was carried out by thermal method. HNO3 5 M was used to remove the template ion by shaking the polymer for 24 hours in several times to obtain leached IIP particles (Pb-IIPs). Non-Imprinted Polymers (NIPs) as control were similarly prepared without imprinted ion. In this study, two types of NIPs were made including with and without the addition of PAR ligands (NIP and NIPP). All polymer particles were characterized by spectral (FTIR), thermal (TGA-DTG), morphology (SEM), and nitrogen adsorption studies (BET). The adsorption and selectivity studies for lead ion were carried out with Pb-IIP, NIPP, and NIP. The adsorption of 20 mg.L-1 of lead(II) using 25 mg of polymer particles in the pH 6 with interaction time 90 min. Maximum adsorption capacity of leached Pb-IIP was found to be 14.3 mg.g-1. The Pb-IIPs displayed excellent selectivity againts three common divalent ions Cu(II), Cd(II), and Zn(II) with selectivity coefficient for each metal ions are 19.98, 42.15, and 42.96, respectively, showing high anti-interfere ability. The precision for the method (% RSD) to be 2,9 % for five times the replication of the adsorption measurement. A high percentage of recovery values ranging from 97-103 %, indicating its accuracy.

The development of real-time, highly sensitive and selective, simple technique for detection of toxic Pb2+ in water was challenged. However, in this study a highly efficient fluorescent probe based on polythiophene imprinted CeO2 nanocomposite for selective detection of Pb2+ ion was developed by polymerization method. The developed fluorescent probe was characterized by using powder X-ray diffraction (XRD), Fourier- Transform Infrared spectroscopy (FT-IR) and Scanning Electron Microscope (SEM). Upon binding to the imprinted binding sites PT/CeO2 the Pb2+ interacts with the molecular orbital and their fluorescence is quenched via reverse photoinduced electron transfer which result the qualitative and quantitative detection. The factor affecting the detection system such as pH and concentration are optimized. Additionally, the PT/CeO2 fluorescent sensor exhibits highly sensitive with stern Volmer quenching (KSV) value of 6.39 x 103 M-1. The practical application of the sensor also tested by spiked with different concentration of Pb2+ ion solutions on tab water samples. The result indicates a good linear relation between FO/F and the spiked concentrations with coefficient of regression R2 = 0.99 (n= 3) and also confirms that the found values is agreed well with the spiked amount. The obtained amounts of lead metal ion concentrations in tap water were 15.39 μM which exceeded the allowable limit as stated by WHO.

This study presents the evaluation of heavy metal removal using Phragmites australis (Cav.) and Schoenoplectus californicus (C.A. Mey.) in a laboratory wetland test (10-days). Two digestion methods Dry Ashing (DA) and Wet Digestion (WD) to determine the final concentration of heavy metal in roots and stems of both plants were used. The final concentration of Cu (5.14 ug.g-1), Zn (27.34 ug.g-1) and Fe (107.91 ug.g-1) were determined in the roots of the Schoenoplectus californicus (C.A. Mey.). While in its stems the highest concentration of Pb (1.69 ug.g-1) was founded. In Phragmites australis (Cav.) the high concentrations of Cu (2.44 ug.g-1), Zn (5.22 ug.g-1) and Fe (28.10 ug.g-1) are found in the roots and Pb (0.70 ug.g-1) in the stems. Regardless of the plants studied, the WD method was the most suitable pretreatment method for determining Cu and Fe concentrations, while the DA method was the best for Zn and Pb.

A new magnetic nanocomposite was prepared by synthesizing Fe3O4@SiO2 nanoparticles and then coating them with a shell of tragacanth gum (TG) as a natural product modified by citric acid (CA). The obtained Fe3O4@SiO2@TG@CA nanoparticles were identified by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and Fourier transform infrared spectroscopy (FT-IR). The prepared magnetic nanoparticles were used for loading and delivery of ranitidine, an oral drug. Conditions for drug loading were optimized by a central composite design optimization method. The maximum loading efficiency for ranitidine was 79.3% that was obtained at pH 11 and its in vitro release was gained within 55 min at pH 1.6 in a phosphate buffer medium. The loading capacity of the nanocarrier was dependent on the initial concentration of ranitidine and exceeded 11.4 mg g-1 in a solution of 200 mg L-1. The study of adsorption isotherms to describe the interaction of ranitidine with the carrier showed the best fit with Freundlich isotherm. The results showed that the prepared Fe3O4@SiO2@TG@CA adsorbent, as a non-toxic and low-cost nanocarrier, is quite suitable for drug delivery applications.