Current Analytical Chemistry - Volume 19, Issue 10, 2023

This review provides a comprehensive examination of the application of fluorescence materials for the detection of latent fingerprints in forensic sciences. Traditional methods like powder dusting, cyanoacrylate fuming, chemical methods, and small particle reagent techniques have shown limitations due to issues like low contrast, sensitivity, selectivity, and high toxicity. To overcome these drawbacks, recent focus has shifted towards using fluorescent materials, owing to their unique optical and chemical properties. This review underscores the importance of latent fingerprint development employing metal nanoparticles, semiconductor nanoparticles, and organic fluorescence compounds. These advanced materials not only provide heightened contrast, sensitivity, and selectivity compared to traditional methods but also manifest diminished toxicity. In essence, the review delivers a methodical survey of these pioneering techniques.

Background: In this work, the reduced graphene oxide decorated with gold nanoparticles (Au/rGO) had been synthesized on glass carbon electrode (GCE) using a simple one-step electrochemical method. The molecularly imprinted poly(p-aminobenzoic acid) (PABA) film was prepared for the analysis of sunset yellow (SY) on Au/rGO/GCE by electropolymerization of p-aminobenzoic acid (pABA) and SY.Methods: Methods, such as scanning electron microscope (SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) were used to characterize the successful formation of imprinted films.Results: Under optimized experimental conditions, the Au/rGO/GCE based molecularly imprinted sensor (MIP/Au/rGO/GCE) exhibited excellent performance for SY, and a linear range was obtained from 0.002 μM to 8 μM with a detection limit of 0.5 nM. The responses of the imprinted sensor maintained higher than 93% of the initial values after 15 days of storage.Conclusion: The MIP/Au/rGO/GCE has been used for the sensitive and selective detection of SY in real food samples with acceptable recoveries, the combination of Au and rGO significantly improved the sensitivity of the proposed sensor due to the synergistic effect of gold nanoparticles and rGO. The resulting sensor also exhibited satisfactory reproducibility and stability, and the proposed platform could be further expected for the detection of other food additives and various electroactive species.

Background: Single nucleotide polymorphisms (SNPs) are important hallmarks in various pathological activities, especially genetic and inherited diseases, and detecting them with accuracy, high throughput and low cost becomes increasingly necessary.Methods: Herein, we have developed a new label-free and sensitive detection method for SNPs assay. Due to its favorable traits, the method presents an excellent performance. Briefly, the peroxidase- mimicking catalytic activity of G-quadruplex-hemin DNAzymes ensures label-free and colorimetric SNPs detection. At the same time, the RNA enzyme of the specific cleavage action can easily achieve the recycling of RNA enzyme and signal amplification.Results: In this study, the P-hemin DNAzyme with target DNA could catalyze the H2O2-mediated oxidation of ABTS to cause an observed color change compared to mutant DNA. The sensitivity and detection range of the DNA biosensor was achieved through the signal amplification program of special binding and cleavage of RNase H. A linear dependence of the absorbance at 420 nm on the concentrations between 0.5 and 50 nM was obtained (R2=0.965), and the detection limit was 8.76 nM.Conclusion: A new strategy for signal amplification process based on RNase cleavage reaction and Catalytic Beacon was constructed. Collectively, the developed SNPs assay might be extended to a broad range of clinical early diagnosis and treatment of genetic diseases.

Aims: The main goal of this research was to find a simple, selective, sensitive and rapid protocol for the detection of traces of levofloxacin (Lev) in seawater, pills, urine, and human plasma samples by using a novel sorbent made of molecularly imprinted polymer (MIP) for its pipette-tip micro-solid phase extraction (PT-μSPE), followed by spectrophotometry. Parameters affecting the method were evaluated employing one-variable-at-a-time, Box-Behnken design (BBD) and central composite design (CCD) techniques, and results were compared together.Background: Lev, the active L-isomer isolated from racemic of loxacin, is a fluoroquinolone (FQ) antibiotic that is widely in use for curing infectious diseases due to its high activity against a large spectrum of both Gram-positive and Gram-negative bacteria. If it enters the environment, such as seawater, due to low degradation, it can remain there for the long term. Besides water, since Lev cannot be metabolized completely in the body, a selective and sensitive protocol for the analysis of Lev in biological fluids is necessary for physiological pharmacokinetics and clinical diagnosis.Objective: The objective was to find a fast, accurate and sensitive method for the determination of Lev in different sample matrices. This method should be very economical as well.Methods: This technique is based on using molecularly imprinted polymer adsorbent for pipette tip micro solid-phase extraction of Lev prior to its spectrophotometric detection.Results: The limit of detection of the developed protocol was 0.1 μg L^-1, and its linear range was 1.0- 1,000.0 μg L^-1 (R²=0.9934). The total time of analysis, including microextraction, was less than 10 min and for the analysis, a sample volume of 14 mL was adequate. 2.0 mg of the sorbent was sufficient for the extraction, and the sorbent could be reused for 4 times without loss in its extraction performance. For the spiked real samples at three levels, recoveries were in the range of 97.4% to 99.5%, with relative standard deviations better than 4.7%.Conclusion: The proposed protocol has advantages, including the simplicity of sorbent preparation and operation, consumption of a low amount of solvent and sorbent, which is in consistency with green chemistry, and high enrichment factor. In addition, it can be applied in samples with different matrices, has low analysis time (10 min), and uses inexpensive instruments.

Background: It has become increasingly important to use non-toxic nanomaterials for treating industrial wastewater that contains organic dyes, such as methyl green.Method: A sol-gel method was used to synthesize aluminum oxide nanoparticles from waste aluminum and investigate the physicochemical process involved in their removal from methyl green.Result: The synthesized adsorbent was characterized using EDX, UV-visible, SEM, FTIR, XRD, and HRTEM techniques. The effects of various parameters, such as the initial concentration, the contact time, and the mass of the adsorbent, were studied for the removal of methyl green in the sunlight, dark, sonication and under UV radiation. It was suspected that Al2O3 nanoparticles and methyl green dye interacted electrostatically in water to cause degradation. The degradation rates of 15 mg/L methyl green were 94.13% and 82.33% after 15 min using ultrasound and UV light. While 70% and 3.33% of the dye degraded after 20 min under sunlight and in the dark.Conclusion: These readily made nanoparticles may well prove useful in wastewater treatment.

Introduction: More than sixteen countries are infected with the highly pathogenic avian influenza A-H5N1 virus. As the virus circles the world, it has led to the slaughter of millions of poultry birds as well as the infection of farmed mink in Europe and among seals and grizzly bears on the Northern coast of America; some infected mammals exhibited neurological symptoms like disorientation and blindness, which marks the first large H5N1 outbreak potentially driven by mammal-tomammal transmission that could be poised to spillover into humans its mortality rate in humans exceeds 50%. The virus pandemic potential is continuously monitored to characterize further and analyze its zoonotic potential (PAHO/WHO, March 2023).Objective: To gain comprehension of the envelope glycoproteins that express H5N1 influenza (hemagglutinin and neuraminidase proteins), computational studies were carried out.Methods: Calculating each sequence's Protein Intrinsic Disorder Predisposition (PIDP) and Polarity Index Method Profile 2.0 v (PIM 2.0 v) required the employment of multiple computer algorithms.Results: The analysis of the PIM 2.0 v and PIDP profiles revealed specific patterns within the envelope glycoproteins (neuraminidase and hemagglutinin) of diverse strains of the H5N1 influenza virus. These patterns made it possible to identify structural and morphological similarities.Conclusion: Using the PIM 2.0 v profile, our computational programs were able to identify the influenza H5N1 virus envelope glycoproteins (hemagglutinin and neuraminidase strains). This study contributes to a better comprehension of this emerging virus.