Analytical and Bioanalytical Chemistry Research
Volume:11 Issue: 3, Summer 2024

The recent decade has seen a huge impact of nanotechnology in different sciences. In analytical chemistry, nanomaterials have been utilized for various purposes from sample preparation to detection. The impact of nanotechnology in analytical science is not limited to the improvement of analytical methodologies. Nanomaterials have been utilized for nanomaterials analysis as nanotools. Nanotools are used to investigate and work with materials at the nanoscale. Nanotechnology has also enabled new applications such as nanoscale tips used for topological microscopy in atomic force microscopy, scanning tunneling microscopy, and magnetic force microscopy. These techniques utilize nanotechnology to improve their efficiency. Furthermore, nanotechnology has enabled the construction of tweezers and robots in the nanoscale. These nano-enabled tools (nanotools) have been successfully utilized for nanoanalysis and nanomanipulation. atomic force microscopy, scanning tunneling microscope, and magnetic force microscopy are not only meant to image nanostructured surfaces but also they are utilized for the manipulation of materials at the atomic and nanoscale. Nanotweezers, nanorobots, and laser tweezers using nanoapertures are also able to manipulate nano and microscale materials. This paper reviews the principles and application of the mentioned nano-enabled techniques as nanotools in analytical chemistry with a focus on nanomaterials nanoanalysis and nanomanipulation as nanoanalytes.

Herein, a green synthesis methodology for making copper oxide (CuO) nano particle cluster in a cost effective and a simple way is reported. While cuprous sulfate pentahydrate is used as a source of copper, the outer layer of green peas (Pisum Sativum) is used as a source of phenol. Extracting the phenol from pea peels is a simple process that uses water as a solvent. Copper salt is reduced by the phenolic content that is so produced. Both physico-chemical and microscopic characterization Scanning Electron Microscope (SEM), Energy-dispersive X-ray (EDX) analysis (EDAX) were performed on the particles. A variety of pea peeling samples were used during the procedure' several executions to ensure reproducibility. The preparation process was appropriate, as the outcomes were identical. Analyses were also conducted on the produced particles' electro-chemical activity as an application. A well-defined and organized redox reaction was seen at E' = +0.25 V against Ag/AgCl which were also shown to be highly electro-active in nature. With the benchmarked redox mediator (5 mM ferricyanide), the particles also produced an outstanding redox peak at E1/2= -0.01 V vs. Ag/AgCl. In a common reducing organic reaction, such as the reduction of p-nitro phenol to p-amino phenol, they were also found to be an effective catalysts. Additionally, tests were conducted on the produced particles' for there anti-bacterial and antifungal properties. Overall, a simple method for formation of commercially viable CuO nano particle cluster is developed with a potential of diverse applications.

This research investigates the usage of pipette tip micro solid phase extraction for the separation of 6-mercaptopurine of complicated matrices before its spectrophotometric detection. To overcome the non-selectivity of spectrophotometry, an ethylene glycol dimethacrylate-based molecularly imprinted polymer was prepared and applied as an adsorbent, which enabled selective and fast extraction of the analyte. To improve the transfer of the analyte to the adsorbent, salting-out effect was employed by the addition of 300 mg of NaCl to the sample before performing microextraction. Variables affecting the microextraction of the protocol were investigated utilizing two ways of one-factor-at-a-time and response surface methodology, which showed good consistency with each other. Extraction parameters were optimized as pH of sample = 9.0, sample volume = 10 mL, amount of adsorbent = 2.0 mg, eluent = 250 µL of methanol:acetonitrile (1:5 v/v), and extraction and elution cycles of 10 and 12 times, respectively. The dynamic linear range of the protocol was 1.0–1000.0 µg L-1, with a limit of detection of 0.25 µg L-1. The method was compared with extraction by a non-imprinted polymer. The extraction efficiency of the analyte obtained from 96.0% to 99.8%, by relative standard deviations better than 5.3%. The suggested technique was employed to determine 6-mercaptopurine in seawater and body fluid samples, and the results were validated by comparing them to a standard HPLC method. The whole analysis time, including microextraction, was about 25 minutes and to perform this method, the sole instrument required is a conventional spectrophotometer.

In this study, reduced graphene oxide (RGO) was first synthesized and then it was reacted by alizarin red S (ARS) and therefore RGO functionalized with ARS was prepared (ARS/RGO). Then, structural analysis of the manufactured material was done by SEM and FTIR techniques. The FTIR results were confirm the interaction between ARS and RGO and the formation of ARS/RGO. A new electrochemical sensor was fabricated on the surface of a glassy carbon electrode modified with ARS/RGO. The prepared electrode showed a quasi-reversible electrochemical behavior and also had a significant effect on the electrocatalytic oxidation of caffeine (CAF). The modified electrode was able to measurement the CAF as an electrochemical sensor. The effect of different parameters was investigated on the oxidation of CAF at the modified electrode; the sensor has the highest current at pH= 4.0. The effect of different interference species on the response of CAF, and also the reproducibility and repeatability of the sensor was investigated and acceptable results were obtained. The electrochemical determination of CAF on the electrode surface was investigated by differential pulse voltammetry and in the linear range of 1.0-100.0 µM, the detection limit value was obtained as 0.022 µM. Finally, the designed sensor was used to measure the amount of CAF in some real samples and satisfactory results were obtained.

Iron oxide nanoparticles have been widely used in various fields of study. Due to the increasing use of these nanoparticles, it is important to develop sensitive methods for measuring these nanoparticles in real samples. In this research, a method was developed to measure magnetite nanoparticles using microfluidics science and paired emitter-detector diode-based photometry. The basis work of the designed system is based on the magnetic preconcentration of nanoparticles inside the microchip, dissolution by acid, and creation of a signal through the formation of an iron-thiocyanate complex. The validation results of the method showed that the linear range of the method is from 1.0 to 6.0 ppm with appropriate accuracy (recovery percentages: 104.0% and 95.6%) and precision (coefficient of variation: 0.17% and 0.15%), which is satisfactory for measuring trace amounts of magnetic nanoparticles. The limits of detection and quantification were obtained as 0.3 and 0.9 ppm, respectively. Compared to previously reported methods, the developed method provides higher sensitivity and simpler instrumentation of lower analysis cost by the use microfluidic chip for magnetic preconcentration of magnetic nanoparticles, washing, dissolution, and photometric determination.

Embelin is the main bioactive chemical in E. ribes berries and possesses various biological properties. Currently, no liquid chromatographic method is available for quantitative estimation of embelin from human plasma. The purpose of this study was to develop an accurate, precise, and simple reverse-phase high-performance liquid chromatographic method for measuring the amount of embelin in human plasma. The separation of embelin was achieved using a Waters C18 (150 x 4.6 mm i.d., 5µ particle size) column. A mixture of acetonitrile and phosphate buffer whose pH was adjusted to 3.6 in a 20:80 v/v ratio and at a flow rate of 1.4 ml/min was employed as a mobile phase. The detection was performed at 289 nm. The plasma extraction method was validated for various parameters, including precision, accuracy, and stability.The developed method using human plasma was linear over a range of 13.9–41.65 ng/µl concentrations with a regression coefficient of 0.984. The accuracy testing revealed the value of the mean percent recovery between 101.54 and 109.15. The mean intra- and inter-day precision of the assay ranged from 105.04 to 91.16% and 0.3628 to 1.4227% RSD, respectively. The extracted samples also showed bench-top and freeze-thaw stability over 72 hours. In human plasma, embelin was found to be stable. The method's validation parameters satisfied the required criteria for acceptance. From the results, we concluded that the developed method can be used for accurate and precise quantification of embelin from human plasma.

The world is currently grappling with unprecedented levels of water pollution, largely attributed to the presence of detrimental chemicals and dyes posing substantial environmental hazards. This study endeavors to develop highly efficient materials capable of extracting anionic dyes from polluted water reservoirs. Utilizing the coprecipitation method, nickel-chrome and zinc-chrome layered double hydroxides (LDH) were synthesized and subsequently analyzed using advanced analytical techniques. The efficiency of both materials in removing anionic dyes Congo Red (CR) and Indigo Carmine (IC) was investigated by analyzing various parameters, including initial solution pH, adsorbent dose, dye concentration, time, and temperature effects. In binary solutions, ZnCr-LDH exhibited a higher adsorption capacity of 109.10 mg/g and 78.64 mg/g for IC and CR dyes, respectively. The competitive removal of a binary dye mixture is primarily influenced by electrostatic attraction. Isotherm models were employed for analysis, with the Freundlich model found to be the best fit for IC adsorption onto NiCr-LDH and the Sips model for IC adsorption onto ZnCr-LDH. In binary systems, the extended Freundlich and non-modified Redlich-Peterson models provided the best fit to the isotherm data. ZnCr-LDH demonstrated higher removal efficiency than NiCr-LDH. Furthermore, both LDH materials exhibited stability and maintained their activity over four successive cycles.

In this study, simultaneous quantification of 2-nitrophenol and 4- nitrophenol in their binary mixtures was investigated spectrophotometrically. Since the signals of analytes were highly overlapped, multivariate partial least squares (PLS) technique was proposed to analyze the data. PLS method makes the analysis possible without the need for separation of analytes by tedious separation procedure or using expensive instrumentation techniques such as chromatographic methods. Both 2-nitrophenol and 4- nitrophenol possess acid-base property and it was required to investigate the effect of pH on the FOM of the calibration. Therefore, at three pH conditions, the calibration processes were evaluated and the results showed the best FOM and the least root mean squares error of prediction (RMSEP) for both analytes were achieved for the augmented data at 3.45 and 8.95 of pHs where only neutral or anionic forms of analytes were present in the solution. The analytical sensitivity, limit of detection, R2 and RMSEP were 108.3 ppm-1, 0.08ppm, 1.00, 0.04 ppm and; 163.2 ppm-1, 0.06 ppm, 0.9999, 0.04 ppm for 2-nitrophenol and 4-nitrophenol, respectively.

As(III) determination is of great importance in various industries such as environmental monitoring, pharmaceuticals, and metallurgy. Therefore, we successfully synthesized and characterized a nanocomposite of sucrose-modified gold nanoparticles (Au@Suc) using UV-visible spectrophotometry and transmission electron microscopy (TEM), in this research. The use of a nanocomposite enabled the development of a microfluidic kit for the colorimetric point-of-care (POC) detection of As(III) ions. The experimental parameters for the microfluidic kit were optimized using the one-factor-at-a-time (OFAT) approach. The effective conditions for the microfluidic kit were found to be a flow rate of 0.15 ml/min, a path length of 5.50 cm, and a pH of 7.0. The resulting microfluidic kit indicated a direct correlation between the red component of RGB pixels in images captured by a smartphone and the concentration of As(III) ions in the range of 0.09-1.20 µmol L-1, with a detection limit of 0.054 µmol L-1. Evaluation of the microfluidic kit's selectivity revealed no significant interference. Additionally, the microfluidic kit was successfully employed to analyze As(III) in various drinking water samples, with recovery values ranging between 95.01% and 105.00%.