Ecofriendly ratiometric colorimetric determination of mercury(II) ion in environmental water samples using gallic acid-capped gold nanoparticles.

Today, the monitoring and determination of heavy metal pollutants in the environment is an essential requirement for the environmental and research communities. Mercury ion is one of the most hazardous heavy metals, and scientists are trying to develop new methods for its detection. In this study, a new colorimetric sensor based on aggregation gallic acid-capped gold nanoparticles (GA-AuNPs) for the determination of mercury ions in environmental water samples was presented. The green synthesized GA-AuNPs exhibited a sharp surface plasmon resonance peak at 515 nm. The addition of mercury ions changed the surface properties of GA-AuNPs, resulting in the formation of a new peak near 670 nm due to the aggregation of GA-AuNPs, and an obvious color change from red to purple occurred. Thus, mercury ions were detected based on the change in the absorbance ratio (A670/A515). The developed sensor can determine the mercury ions in the concentration range of 78.0 nM to 8.3 µM with a detection limit of 5.5 nM. Based on the Environmental Protection Agency (EPA) and the World Health Organization (WHO) reports, the amount of Hg2+ ions in fresh water should be between 10.0 and 30.0 nM. The results indicate that the developed sensor can detect and determine trace amounts of Hg2+ ions in environmental water samples.

A paper-based chemical tongue based on the charge transfer complex of ninhydrin with an array of metal-doped carbon dots discriminates natural amino acids and several of their enantiomers.

Simultaneous detection of multiple amino acids (AAs) instead of individual AAs is inherently worthwhile for improving diagnostic accuracy in clinical applications. Here, a facile and reliable colorimetric microfluidic paper-based analytical device (µPAD) using carbon dots doped with transition metals (Cr3+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, and Zn2+) has been provided to detect and discriminate 20 natural amino acids. To make the colourless metal-doped carbon dots suitable for colorimetric assays, they were mixed with ninhydrin to form a charge transfer complex. This optical tongue system, which was constructed by dropping mixtures of ninhydrin with a series of metal-doped carbon dots on a paper substrate in an array format, represented obvious but different colorimetric signatures for every examined amino acid. Since bovine serum albumin was used as a chiral selector reagent for synthesizing the CDs, the sensor device represented excellent selectivity to identify enantiomeric species of AAs. This is the first optical array device that can simultaneously discriminate AAs and several of their enantiomers. We employed various statistical and chemometric methods to analyze the digital data library collected by Image J software, including principal component analysis (PCA), linear discriminant analysis (LDA), and hierarchical cluster analysis (HCA). Twenty AAs could be well distinguished at various concentrations (10.00, 5.00, 2.50, and 1.25 mM). The colorimetric patterns were highly repeatable and were characteristic of individual AAs. Besides qualitative analysis, the designed µPAD-based optical tongue represented quantitative analysis ability, e.g., for lysine in the concentration ranges of 0.005-20.0 mM with a detection limit of 1.0 × 10-6 M and for arginine in the concentration range of 0.12-20.00 mM with a detection limit of 80.0 × 10-6 M. In addition, the binary, ternary, and quaternary mixtures of AAs could also be well recognized with this sensor.

A facile and eco-friendly fluorometric method for the determination of methotrexate and folic acid in biological samples based on hollow luminescent carbon dots and chemometrics method.

A rapid, simple, and inexpensive spectrofluorimetric sensor has been developed for the simultaneous determination of methotrexate (MTX) and folic acid (FA) based on their interactions with hollow carbon dots (HCDs). Since the use of folic acid to cope with the toxic side effects of MTX in patients is essential, the simultaneous determination of these two compounds has been interesting. The results showed that  MTX could quench the fluorescence of HCDs with a dynamic quenching mechanism. The sensor exhibited a linear concentration range of 1.0 × 10-6-1.9 × 10-4 mol L-1 for MTX and 1.5 × 10-5-9.4 × 10-4 mol L-1 for FA and the obtained detection limits for MTX and FA were 1.6 × 10-7 and 5.0 × 10-7 mol L-1, respectively. The applicability of the method was investigated in the analysis of the urine samples and the partial least squares (PLS) method was used for the simultaneous determination of MTX and FA.

Colorimetric determination of peroxide value in vegetable oils using a paper based analytical device.

Peroxide value (PV) is one of the most typically used quality parameters to monitor lipid oxidation. Here, a simple paper-based analytical device (PAD) has been developed to determine PV in vegetable oils. The analysis is based on setting up the iodometric titration, where hydroperoxides in the oil are reacted with excess iodide ions to generate iodine molecules, on the paper substrate. The device is composed of two paper layers acting as reaction and detection zones, aligned in a metallic mold. A well-defined inverse logarithmic calibration curve was established between the measured PV by the official iodometric method (ISO;3960, 2017) and the color intensity of PAD. It offered a working range of 0.01-30.0 meq/Kg. The limit of detection of 0.015 meq/Kg demonstrated enough sensitivity of the method to estimate peroxide value in edible oils. On-site and visual detection, low cost, simplicity, and less solvent consumption are advantages of the proposed device.

A poly(arylene ethynylene)-based microfluidic fluorescence sensor array for discrimination of polycyclic aromatic hydrocarbons.

Polycyclic aromatic hydrocarbons (PAHs) are persistent contaminants in the environment. Several of them have carcinogenic properties. There is considerable interest in their sensitive low-cost detection and monitoring. We present a simple paper-based microfluidic sensor for the rapid detection of PAHs. Craft punch patterning generated multiple detection zones inhabited by fluorescent poly(arylene ethynylene)s (PAEs). Changes in fluorescence image and/or intensity of the sensor array were recorded using a smartphone camera. The RGB color values of the photographed images were extracted through ImageJ software. 10 different PAHs were correctly identified using Principal Component Analysis and discrimination analysis (PCA-DA). 100% classification accuracy was achieved for model training, whereas validating the PCA-DA model by cross-validation resulted in 93% classification accuracy for 5.0 mg L-1 analyte.

Paper-Based Optical Nose Made with Bimetallic Nanoparticles for Monitoring Ignitable Liquids in Gasoline.

A paper-based optical nose was fabricated by dropping bimetallic silver and gold nanoparticles on a paper substrate. The nanoparticles were synthesized by both natural (lemon, pomegranate, and orange juices) and chemical (citrate, gallic acid, and ascorbic acid) reducing agents. The performance of the assay was evaluated for identifying gasoline and five ignitable liquids such as diesel, ethanol, methanol, kerosene, and thinner. The interaction of the sensor with sample vapors caused aggregation, consequently changing the color of nanoparticles. The color changes, which were captured by a scanner, represented a specified colorimetric map for each analyte, allowing one to identify the studied fuels. The visual results were confirmed using multivariate statistical analysis such as principal component analysis and hierarchical clustering analysis. Also, partial least-squares regression was used to assist the proposed assay for estimating the amount of studied ignitable liquids as counterfeit species in the gasoline sample. The root-mean-square errors for prediction were 3.4, 2.1, 1.9, 2.0, and 1.7% for diesel, thinner, kerosene, ethanol, and methanol, respectively. Finally, the fabricated sensor indicated high efficiency for the on-site detection of pure industrial gasoline samples from adulterated ones.

A non-invasive tool for early detection of acute leukemia in children using a paper-based optoelectronic nose based on an array of metallic nanoparticles.

Volatile organic compounds (VOCs) in blood samples can be used as useful biomarkers to diagnose various human diseases. This study describes the potential of a paper-based sensor array for detecting leukemia using blood VOCs. Blood samples were collected from 59 new leukemia cases and 47 healthy cases as a control group. Each blood sample was divided into two parts; one for a laboratory test and the other was used in our study. Samples were mixed with heparin and then transferred to a sterile container, and a sensor was stacked on its cap. This sensor array contains 16 nanoparticles deposited on a sheet of hydrophobic paper in a 4 × 4 array format. Containers were stored in an oven at 60 °C for 4.5 h. Then, the image of sensors was recorded by a scanner and compared to the image before exposing the blood vapor. The sensor responses were subjected to different multivariate statistical methods to develop models that discriminate between control and leukemia samples. The interaction of nanoparticles with the volatile metabolome of blood caused aggregation and consequently changing in the color of nanoparticles. The color changes resulted in a specific pattern for blood samples with leukemia, which is different from those obtained from healthy specimens. The discrimination analysis was approved by pattern recognition methods such as principal component analysis with 97% accuracy. Among 59 patients, the mean age was 6.02 ± 4.55 years (range 1-16 y). The mean total response was 652.83 ± 117.02. The rock curve showed an accuracy of 96% for classifying patients from the control group. The logistic regression model showed that 93.6% of healthy and 93.2% of patients were classified correctly by using this method. These statistics agree with the classification results obtained by principal component analysis. For every 5000-unit increase in platelet count, the chance of leukemia decreased by 9%. Additionally, the chance of being categorized as a patient decreased by 10% for every 20-unit increase in total response. The electronic nose using VOC's of blood is a non-invasive and inexpensive tool for detecting new cases of leukemia with high sensitivity and specificity. Platelet count is an essential para-clinical parameter determining the total response of the sensors. Follow up studies with a larger sample size are warranted to elucidate its clinical applicability.

A paper-based colorimetric sensor array for discrimination of monofloral European honeys based on gold nanoparticles and chemometrics data analysis.

A sensitive and simple nanomaterial based colorimetric sensor array (NBCSA) was developed for discrimination of monofloral honey from various European countries based on three botanical origins as Acacia, Canola and Honeydew. The NBCSA was designed by spotting gold (AuNPs) and silver (AgNPs) nanoparticles synthesized using six different reducing and/or capping agents. The colour intensity of AuNPs represented differential changes when interacting with volatile organic compounds appeared in the headspace of the honey samples. The color difference maps, which are calculated as the difference between color intensity of the sensor before and after exposing to the sample vapors, were used as a fingerprint to discriminate the honey samples based on botanical origin. Classification was achieved utilizing data pre-processing and chemometrics data analysis. Fitting accuracies of 88% and 86% were obtained by partial least squares discriminant analysis and linear discriminant analysis whereas 100% was achieved using support vector machine.

A 3D origami paper-based analytical device combined with PVC membrane for colorimetric assay of heavy metal ions: Application to determination of Cu(II) in water samples.

Microfluidic paper-based analytical devices (µPADs) as a potentially powerful analytical platform have recently gained significant attention for on-site monitoring of heavy metal ions, which are one of the most significant environmental concern because of non-degradability and high toxicity. The commonly applied µPADs suffers from some defects, such as heterogeneous deposition of reagent, resulting in poor detection limits and low sensitivity. So, in this work, a three-dimensional origami µPAD combined with PVC Membrane was developed, which can manage problems of movement of colored products or leaching out the dye and leading to color heterogeneity in the detection zones. Furthermore, a waste layer was added to µPAD for loading of more amounts of the analyte, which results in improvement of detection limit. As a proof of concept, the µPAD was used for the analysis of Cu2+ ion. For this purpose, pyrocatechol violet and chrome azurol S as colorimetric reagents were doped into PVC membrane and injected in the detection zone. The proposed µPAD was presented good linearity in the ranges of 5.0-1400.0 and 5.0-200.0 mg L-1, and the limits of detections of 1.7 and 1.9 mg L-1 in presence of chrome azurol S and pyrocatechol violet, respectively.

Ultrasound-assisted synthesis of chiral cysteine-capped CdSe quantum dots for fluorometric differentiation and quantitation of tryptophan enantiomers.

A room temperature ultrasound-assisted method was applied to synthesize L- and D-cysteine-capped CdSe quantum dots (QDs). The QDs were characterized by XRD, FT-IR, and TEM. They have diameters of 5-7 nm and are shown to be viable probes for highly selective chiral recognition of tryptophan (Trp) enantiomers by fluorometry. The green fluorescence of the capped QDs (with excitation/emission maxima at 380/527 nm and 380/520 nm for L-Cys and D-Cys QDs, respectively) is differently quenched by D- and L-Trp in a high selective manner, with negligible interference by other species. The calibration plots and corresponding Stern-Volmer plots for both Trp enantiomers were investigated by two different approaches: In the first, each individual enantiomer was tested. In the second, each enantiomer was tested in the presence of a 100-folds excess of the other enantiomer. The detection limits for the recognition of L- and D-Trp are 4.2 and 4.7 nM, respectively, for the first approach. In the presence of the other enantiomer, the LODs are 4.4 and 4.8 nM. The linear range extends from 0.1 to 15 µM for both enantiomers. Graphical abstractSchematic representation of tryptophan (Trp) chiral recognition process. The fluorescence (green, ON) of D- and L-Cys (cysteine)-capped CdSe QDs is quenched (black, OFF) through a preferential and selective interaction with L- and D-Trp, respectively.

A carbon paste electrode modified with a metal-organic framework of type MIL-101(Fe) for voltammetric determination of citric acid.

A carbon paste electrode (CPE) modified with a metal-organic framework composite of type MIL-101(Fe) is described for determination of citric acid (CA). The electrochemical activity of the modified CPE was studied by cyclic voltammetry and differential pulse voltammetry. Scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, N2 adsorption-desorption isotherms and X-ray powder diffraction were used for characterization of the MIL-101(Fe). Under optimized electrochemical conditions, the anodic peak current, best measured at working potentials around 0.02 V (vs. Ag/AgCl); decreases linearly in the 5.0 to 100 µM CA concentration range, and the detection limit is 4.0 µM (at S/N = 3). The electrode exhibits good selectivity for CA, with no significant interference in the wide pH range of 3.0 to 9.0. The electrochemical sensitivity of the MIL-CPE is -0.67 µA·µM-1·cm-2. The method was successfully applied to the determination of CA in some commercial beverages. The good recoveries (98-102%) and the agreement of data with those obtained by HPLC indicate the applicability of the method. Graphical abstract Schematic presentation of a new modified carbon paste electrode based on the metal-organic framework of type MIL-101(Fe) for the simple and sensitive determination of citric acid. The results show the MIL-101(Fe)-modified electrode to have good selectivity for citric acid and to enable real sample analysis.

Structural Elucidation and Ultrasensitive Analyses of Volatile Organic Compounds by Paper-Based Nano-Optoelectronic Noses.

Paper-based optoelectronic noses (OENs) are being developed based on printing of organic and organometallic reagents on hydrophilic substrates that can visualize the odor of volatiles. In this work, we report for the first time the use of nanoparticles for fabrication of novel paper-based OENs, which represent much higher sensitivity and produce simple but discriminant colorimetric signature of volatile metabolomes. This nano-optoelectronic nose (NOEN) system, which is fabricated by dropping of gold and silver nanoparticles (each synthesized by 8 chemical species) on the paper, gives obvious colorimetric signatures for chemicals having individual or combined functional groups. Owning to their ultrasensitivity, these simple devices need very small amounts of analytes. These devices could detect and discriminate 45 volatile organic compounds in 9 chemical families including phenols, alchohols, ketones, aldehydes, amines, acids, esters, arenes, and hydrocarbons. In addition to excellent discrimination ability, this NOEN sensor shows ultrahigh sensitivity such that could determine volatile compounds with detection limits around or lower than 10 ppb. Moreover, it can be combined with multivariate calibration methods for quantitative analysis of a metabolite in a complex mixture.

Ascorbic Acid Determination Based on Electrocatalytic Behavior of Metal-Organic Framework MIL-101-(Cr) at Modified Carbon-Paste Electrode.

Background: Metal-organic frameworks (MOFs) are classified as microporous materials. They have large surface areas, low framework densities, accessible cages, and tunnels with modifiable pores. Objective: The MOF MIL-101(Cr) with a large pore volume was synthesized hydrothermally and used in the electrochemical reactions as an electrocatalyst for the determination of ascorbic acid (AA). The synthesized MOF was characterized by scanning electron microscopy and X-ray powder diffraction. Methods: The electrocatalytic behavior of a carbon-paste electrode modified with MIL-101(Cr) was studied through electro-oxidation of AA by cyclic voltammetry and square wave voltammetry. The conventional three-electrode cell system, consisting of Ag/AgCl (3 M KCl) as the reference, platinum wire as the counter electrode, and modified carbon paste as the working electrode, was used in the experiment. Results: Under optimized experimental conditions, the electrode revealed a linear relationship between the oxidation peak current and concentration of AA over a wide range from 0.01 to 10 mM with the LOD of 0.006 mM (3 Sb/m). The results showed that 100-fold of Na+, K+, Mg²+, Ca2+, Cl-, SO42-, sorbitol, sucrose, fructose, citric acid, 40-fold of NO3-, glucose, sucrose, urea, and 10-fold of uric acid had no significant interference. The method was adapted for the determination of the concentration of AA present in two real samples (vitamin C tablet and vitamin C effervescent tablet) with recovery of 97.0 and 96.0%, respectively. Conclusions: A simple, sensitive and reliable modified electrode has been established and applied for the determination of AA. Highlights: The modified electrode represented a good performance in the analysis of the real sample.

An optoelectronic tongue based on an array of gold and silver nanoparticles for analysis of natural, synthetic and biological antioxidants.

A colorimetric array, which can discriminate 20 food antioxidants of natural, synthetic and biological groups, is described. It consists of gold and silver nanoparticles that were synthesized using six different reducing and/or capping agents. The function of the array relies on the interaction of the antioxidants with the nanoparticles which causes aggregation or morphological changes. This, in turn, causes a change in the sensors' colors. The array produces a unique combination of colors for each antioxidant. The resulting colorations are determined by recording the absorbances of the arrays at wavelengths of 405, 450, 490 and 630 nm, or by capturing the images with a digital camera. The discriminatory ability of the array is investigated by principle component analysis and hierarchical cluster analysis. The method was applied to quantitative assay of gallic acid, caffeic acid, catechin, dopamine, citric acid, butylated hydroxytoluene and ascorbic acid. The respective limits of detection are 4.2, 13, 53, 6.9, 47, 3.5 and 43 nM, respectively. The simultaneous determination of 5 different antioxidants is achieved utilizing partial least square regression. The root mean square errors for prediction of the test set are 0.0650, 0.0782, 0.811, 0.0206 and 0.135 nM for gallic acid, catechin, butylated hydroxytoluene, dopamine, and ascorbic acid, respectively. This method demonstrates excellent potential for analysis of antioxidants in beverages such as tea and lemon juice. Graphical abstract Schematic of a method for the simultaneous determination of several antioxidants based on changes in the color of gold and silver nanoparticles. The antioxidants cause aggregation and/or morphological changes which can be detected by using both image analysis or by colorimetry.

Topical delivery of chitosan-capped silver nanoparticles speeds up healing in burn wounds: A preclinical study.

This study investigated the effects of topical application of chitosan-capped silver nanoparticles (Ch/AgNPs) on burn wound healing. The chitosan-capped silver nanoparticles were synthesized in one step from the silver nitrate, sodium borohydride, and chitosan and were characterized using transmission electron microscopy, fourier transform infrared spectroscopy, and X-ray diffraction methods. The antioxidant assay was performed to evaluate the scavenging rate. The effects of Ch/AgNPs on burn wound healing was also evaluated by histopathological, molecular, and biochemical evaluations after 7, 14 and 28 days of treatment in a rat model. In comparison to the negative control and silver sulfadiazine groups, the Ch/AgNPs treated wounds exhibited significantly lower inflammatory reaction as determined by the reduced level of interleukin-1ß (IL-1ß) and neutrophil counts. Treatment by Ch/AgNPs also significantly enhanced re-epithelialization, so that complete epithelialization was achieved in the lesions of the animals of this group, at the 7th day post-wounding. Rapid re-epithelialization, improved granulation tissue formation, reduced IL-1ß expression, mild inflammation, and increased transforming growth factor-ß1 and basic fibroblast growth factor, at 7 days post-wounding, are convincing reasons to confirm this idea that Ch/AgNPs are effective in speeding up the wound healing stages. Our histopathological findings are in agreement with the molecular and biochemical results and strongly demonstrate that Ch/AgNPs stimulate burn wound healing by decreasing the length of repair phases. Therefore, on the basis of our findings, Ch/AgNPs can be a promising candidate in stimulating wound repair and regeneration.

A new bifunctional nanostructure based on Two-Dimensional nanolayered of Co(OH)2 exfoliated graphitic carbon nitride as a high performance enzyme-less glucose sensor: Impedimetric and amperometric detection.

A novel non-enzymatic glucose sensor was constructed based on the nanolayered Co(OH)2 deposited on polymeric graphitic carbon nitride (Co(OH)2-g-C3N4) via chemical bath deposition. The two-dimensional nanocomposite was used to modify a carbon paste electrode and its electrochemical performance of electrode was carefully evaluated. The electrochemical oxidation of glucose at modified electrode was studied by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in 0.2 M KOH. It revealed a remarkable electrocatalytic behavior and noticeably synergistic effect as a result of decent exfoliation of graphitic carbon nitride in the presence of Co(OH)2. The amperometric response achieved by the modified electrode showed two calibration ranges with an excellent selectivity. A single-frequency impedance method was applied for glucose determination as an alternative to conventional EIS methods. The developed sensor represents a high sensitivity, wide concentration range (25 µM - 420.0 mM by impedimetry and 6.6-9800 µM by amperometry), and high reproducibility. The modified electrode showed a good selectivity for glucose over potentially interfering materials such as dopamine, ascorbic acid, urea, and uric acid. Finally, the Co(OH)2-g-C3N4-CPE was utilized for quantification of glucose in blood serum samples.

Sonication-assisted preparation of a nanocomposite consisting of reduced graphene oxide and CdSe quantum dots, and its application to simultaneous voltammetric determination of ascorbic acid, dopamine and uric acid.

Cadmium selenide quantum dots were capped with reduced graphene oxide that was modified with thioglycolic acid. The nanocomposite was prepared by 5-min sonication of a solution of graphene oxide, thioglycolic acid, and cadmium(II) nitrate and selenium powder in the presence of NaBH4. X-ray diffraction and transmission electron microscopy were used to characterize the nanocomposite. A glassy carbon electrode (GCE) was modified with this nanocomposite and used for simultaneous determination of dopamine (DA), ascorbic acid (A) and uric acid (UA). The modified GCE was characterized by using cyclic voltammetry and differential pulse voltammetry. Simultaneous determination of AA, DA and UA was accomplished at working voltages of -50, +148 and + 280 mV (all vs. Ag/AgCl), respectively. The voltammetric response to DA is linear in the 4.9 to 74.0 µM concentration range, and the detection limit (defined as 3σ of the blank) is 0.11 µM. The respective data are 0.39-1.0 mM and 66 µM for AA, and 9.0 to 120.0 µM and 0.12 µM for UA. The electrode was successfully applied to the determination of the 3 species in spiked urine samples. Graphical abstract Graphical abstract contains poor quality of text in image. Otherwise, please provide replacement figure file.Thank you for your comment. New garaphical abstract was attached. A sonochemical method was applied for synthesizing reduced graphene oxide decorated thioglycolic acid capped cadmium selenide quantum dots. A modified glassy carbon electrode was prepared for simultaneous determination of ascorbic acid, dopamine and uric acid.

Chiral recognition of tryptophan enantiomers using chitosan-capped silver nanoparticles: Scanometry and spectrophotometry approaches.

A new, fast and inexpensive colorimetric sensor was developed for chiral recognition of tryptophan enantiomers using chitosan-capped silver nanoparticles. The function of the sensor was based on scanometry and spectrophotometry of the colored product of a reaction solution containing a mixture of chitosan-capped silver nanoparticles, phosphate buffer and tryptophan enantiomers. The image of the colored solution was taken using the scanometer and the corresponding color values were obtained using Photoshop software which subsequently were used for optimization of the experimental parameters as the analytical signal. Two types of color values system were investigated: RGB (red, green and blue values) and CMYK (cyan, magenta, yellow and black values). The color values indicated that L-tryptophan had better interaction than D-tryptophan with chitosan-capped silver nanoparticles. A linear relationship between the analytical signal and the concentration of L-tryptophan was obtained in the concentration range of 1.3 × 10-5-4.6 × 10-4molL-1. Detection limits, were obtained to be 2.1 × 10-6, 2.4 × 10-6 and 3.8 × 10-6molL-1 for L-tryptophan based on R (red), G (green) and B (blue) values, respectively.

Chiral recognition of naproxen enantiomers based on fluorescence quenching of bovine serum albumin-stabilized gold nanoclusters.

A simple, fast and green method for chiral recognition of S- and R-naproxen has been introduced. The method was based on quenching of the fluorescence intensity of bovine serum albumin-stabilized gold nanoclusters in the presence of naproxen enantiomers. The quenching intensity in the presence of S-naproxen was higher than R-naproxen when phosphate buffer solution at pH7.0 was used. The chiral recognition occurred due to steric effect between bovine serum albumin conformation and naproxen enantiomers. Two linear determination range were established as 7.4×10-7-9.1×10-6 and 9.1×10-6-3.1×10-5molL-1 for both enantiomers and detection limits of 7.4×10-8molL-1 and 9.5×10-8molL-1 were obtained for S- and R-naproxen, respectively. The developed method showed good repeatability and reproducibility for the analysis of a synthetic sample. To make the procedure applicable to biological samples, the removal of heavy metals from the sample is suggested before any analytical attempt.

Synthesis and application of molecularly imprinted nanoparticles combined ultrasonic assisted for highly selective solid phase extraction trace amount of celecoxib from human plasma samples using design expert (DXB) software.

In this work molecular imprinted nanoparticles (MINPs) was synthesized and applied for ultrasonic assisted solid phase extraction of celecoxib (CEL) from human plasma sample following its combination by HPLC-UV. The MINPs were prepared in a non-covalent approach using methacrylic acid as monomer, CEL as template, ethylene glycol dimethacrylate as cross-linker, and 2,2-azobisisobutyronitrile (AIBN) as the initiator of polymerization. pH, volume of rinsing and eluent solvent and amount of sorbent influence on response were investigated using factorial experimental design, while optimum point was achieved and set as 250mg sorbent, pH 7.0, 1.5mL washing solvent and 2mL eluent by analysis of results according to design expert (DX) software. At above specified conditions, CEL in human plasma with complicated matrices with acceptable high recoveries (96%) and RSD% lower than 10% was quantified and estimated. The proposed MISPE-HPLC-UV method has linear responses among peak area and concentrations of CEL in the range of 0.2-2000µgL(-1), with regression coefficient of 0.98. The limit of detection (LOD) and quantification (LOQ) based on three and ten times of the noise of HPLC peaks correspond to blank solution were 0.08 and 0.18µgL(-1), respectively.