Validation of a high-performance liquid chromatography method for determining lysophosphatidylcholine content in bovine pulmonary surfactant medication.

Pulmonary surfactant replacement therapy is a promising improvement in neonatal care for infants with respiratory distress syndrome. Lysophosphatidylcholine (LPC) is an undesirable component that can hinder surfactant proteins from enhancing the adsorption of surfactant lipids to balance surface tensions by creating a saturated coating on the interior of the lungs. A novel normal-phase liquid chromatography method utilizing UV detection and non-toxic solvents was developed and validated for the first time to analyze LPC in the complex matrix of pulmonary surfactant medication. The analytical method validation included evaluation of system suitability, repeatability, intermediate precision, linearity, accuracy, limit of detection (LOD), limit of quantification (LOQ), stability and robustness. The method yielded detection and quantification limits of 4.4 and 14.5 µg/ml, respectively. The calibration curve was modified linearly within the LOQ to 1.44 mg/ml range, with a determination coefficient of 0.9999 for standards and 0.9997 for sample solutions. Given the lack of reliable published data on LPC analysis in pulmonary surfactant medications, this newly developed method demonstrates promising results and offers advantages of HPLC methodology, including simplicity, accuracy, specificity, sensitivity and an exceptionally low LOD and LOQ. These attributes contribute to considering this achievement as an innovative method.

Optimization and characterization of silver nanoparticle-modified luffa for the adsorption of ketoprofen and reactive yellow 15 from aqueous solutions.

In the current work, luffa was modified with silver nanoparticles to prepare LF/AgNPs adsorbent for the elimination of ketoprofen and reactive yellow 15 (RY15) from aqueous media. Various characterization techniques, including FT-IR, XRD, BET, and SEM-EDS analysis, were employed to confirm the successful modification of LF/AgNPs. Several key parameters such as contact time, adsorbent dosage, concentration, pH, and agitation technique were fine-tuned to optimize the adsorption process. Ketoprofen removal was found to be most effective in weakly acidic conditions (pH = 5), while reactive yellow 15 adsorption was enhanced in an acidic environment (pH = 2). At 298 K, the highest adsorption capacities reached 56.88 mg/g for ketoprofen and 97.76 mg/g for reactive yellow 15. In both scenarios involving the elimination of ketoprofen and RY15, the Temkin isotherm exhibits higher R2 values, specifically 0.997 for ketoprofen and 0.963 for RY15, demonstrating a strong correlation with the observed adsorption data. Additionally, the kinetics of ketoprofen adsorption were best described by the Pseudo-first order model (R2 = 0.989), whereas the Pseudo-second order model provided the most accurate fit for reactive yellow 15 adsorption (R2 = 0.997). Importantly, the LF/AgNPs adsorbent displayed consistent performance over five consecutive reuse cycles, affirming its stability and efficacy in removing both contaminants. These findings underscore the exceptional potential of LF/AgNPs as a reliable adsorbent for the removal of reactive yellow 15 and ketoprofen from aqueous solutions.

Preparation of sisal fiber/polyaniline/bio-surfactant rhamnolipid-layered double hydroxide nanocomposite for water decolorization: kinetic, equilibrium, and thermodynamic studies.

Sisal fiber is a potent economical biomaterial for designing composites because of its low density, high specific strength, no toxic effects, and renewability. The present study utilized sisal fiber as a starting material and subjected it to modification to produce a sisal fiber/polyaniline/bio-surfactant rhamnolipid-layered double hydroxide nanocomposite material denoted as SF@PANI@LDH@RL. The composite was evaluated for its efficacy in removing reactive orange 16 (RO16) and methylene blue (MB) from aqueous solutions. The synthesized adsorbent was characterized by FTIR, XRD, and SEM-EDS techniques; these analyses indicated the successful modification of the sisal fiber. The primary factors, including contact time, adsorbent dosage, dye concentration, temperature, and pH, were optimized for achieving the most excellent adsorption efficiency. On the one hand, methylene blue removal is enhanced in the basic solution (pH = 10). On the other hand, reactive orange 16 adsorption was favored in the acidic solution (pH = 3). The highest adsorption capacities for methylene blue and reactive orange 16 were 24.813 and 23.981 mg/g at 318 K, respectively. The Temkin isotherm model, which proves the adsorption procedure of methylene blue and reactive orange 16 could be regarded as a chemisorption procedure, supplies the most suitable explanation for the adsorption of methylene blue (R2 = 0.983) and reactive orange 16 (R2 = 0.996). Furthermore, Elovich is the best-fitting kinetic model for both dyes (R2 = 0.986 for MB and R2 = 0.987 for RO16). The recommended SF@PANI@LDH@RL adsorbent was reused six consecutive times and showed stable adsorption performance. The results demonstrate that SF@PANI@LDH@RL is a perfect adsorbent for eliminating cationic and anionic organic dyes from aqueous media.

Synthesis of UiO-66-Sal-Cu(OH)2 by a Simple and Novel Method: MOF-Based Metal Thin Film as a Heterogeneous Catalyst for Olefin Oxidation.

Metal-organic frameworks (MOFs), particularly UiO-66-NH2, are employed as a catalyst in many industrial catalyst applications. As converting catalysts into thin film significantly increases their catalytic properties for the epoxidation of olefins, we report a general approach to synthesizing MOF thin films (UiO-66-Sal-Cu(OH)2). Using the postsynthesis method (PSM), UiO-66-NH2 was functionalized with salicylaldehyde and entrapped on copper hydroxide nanoparticle surfaces using a modern strategy (MOF thin film). We used field-emission scanning electron microscopy (FE-SEM), EDX (energy-dispersive X-ray analysis), XRD (X-ray diffraction), FT-IR (Fourier transform infrared), BET (Brunauer-Emmett-Teller), TGA (thermogravimetric analysis), XPS (X-ray photoelectron spectroscopy), and ICP-MS (inductively coupled plasma mass spectrometry) to determine the structure and morphology of the synthesized UiO-66-Sal-Cu(OH)2. The oxidation of cyclooctene by the UiO-66-Sal-Cu(OH)2 thin film was studied. Due to its advantages, such as being environmentally friendly (base metal-loaded catalyst, room temperature, solvent-free reaction), reusability, and high yield, this compound can be an appropriate catalyst for the oxidation of olefins.

Facile preparation of sisal-Fe/Zn layered double hydroxide bio-nanocomposites for the efficient removal of rifampin from aqueous solution: kinetic, equilibrium, and thermodynamic studies.

In the present study, sisal-Fe/Zn LDH bio-nanocomposite for efficiently removing rifampin was synthesized using a simple co-precipitation method. SEM, XRD, and FTIR analyses were applied to characterize the prepared composite. In the following, different factors that are affecting the adsorption of rifampin, including contact time, initial rifampin concentration, adsorbent dosage, and temperature were evaluated. Also, the kinetic, isotherm, and thermodynamic studies were investigated. The results indicated that Freundlich (R2 = 0.9976) was a suitable model for describing the adsorption equilibrium and adsorption kinetic showed that the data are in maximum agreement with the pseudo-second-order kinetic model (R2 = 0.9931). According to the Langmuir isotherm model, the maximum adsorption capacity of rifampin was found to be 40.00 mg/g. The main mechanisms for rifampin elimination were introduced as electrostatic attraction and physical adsorption. Moreover, the spontaneity and nature of the reaction were analyzed by elucidating thermodynamic factors that indicated the adsorption process was exothermic and spontaneous. Also, the batch process design indicated that for treating 10 L wastewater containing 100 mg/L rifampin with a removal efficiency of 96%, the needed amount of sisal-Fe/Zn LDH is 51.6 g. This study revealed that the sisal-Fe/Zn LDH bio-nanocomposites as a low-cost adsorbent have promising adsorption potential.

In this study, an innovative bio-nanocomposite (sisal­Fe/Zn layered double hydroxide) has been synthesized using a co-precipitation method for the first time and was used for the removal of pharmaceutical pollutants. Sisal­Fe/Zn LDH exhibited an excellent adsorption capacity of 40.00 mg/g to remove rifampin from the aqueous solution. The main mechanisms for rifampin elimination were introduced as electrostatic attraction and physical adsorption. Also, the batch process design showed that for treating 10 L wastewater containing 100 mg/L rifampin with a removal rate of 96%, the amount of sisal­LDH bio-nanocomposite required is about 51.6 g. Therefore, sisal­Fe/Zn layered double hydroxide as an eco-friendly biosorbent can be considered for future water treatment.

Low-cost treated lignocellulosic biomass waste supported with FeCl3/Zn(NO3)2 for water decolorization.

Dye pollution has always been a serious concern globally, threatening the lives of humans and the ecosystem. In the current study, treated lignocellulosic biomass waste supported with FeCl3/Zn(NO3)2 was utilized as an effective composite for removing Reactive Orange 16 (RO16). SEM/EDAX, FTIR, and XRD analyses exhibited that the prepared material was successfully synthesized. The removal efficiency of 99.1% was found at an equilibrium time of 110 min and dye concentration of 5 mg L-1 Adsorbent mass of 30 mg resulted in the maximum dye elimination, and the efficiency of the process decreased by increasing the temperature from 25 to 40 °C. The effect of pH revealed that optimum pH was occurred at acidic media, having the maximum dye removal of greater than 90%. The kinetic and isotherm models revealed that RO16 elimination followed pseudo-second-order (R2 = 0.9982) and Freundlich (R2 = 0.9758) assumptions. Surprisingly, the performance of modified sawdust was 15.5 times better than the raw sawdust for the dye removal. In conclusion, lignocellulosic sawdust-Fe/Zn composite is promising for dye removal.

Electrospun Polyacrylonitrile/Clinoptilolite Coating for SPME of PAHs from Water Samples.

Electrospun polyacrylonitrile/clinoptilolite (PAN/CP) nanofibers were used to extract polycyclic aromatic hydrocarbons (PAHs) (acenaphthene, acenaphthylene, naphthalene, and phenanthrene) from water samples by solid-phase microextraction (SPME). The target PAHs was detected and quantified by gas chromatography equipped with a flame ionization detector. The PAN/CP fibrous coating with uniform morphology and without beads was electrospun after optimizing the electrospinning parameters by the Taguchi method. Thermogravimetric analysis of PAN/CP nanofibers indicated that the nanofibers are thermally stable up to 357°C. The effective parameters that affect the extraction by SPME were optimized using the response surface methodology based on the central composite design. The limits of detection and limits of quantification by the proposed method were 0.10-0.32 and 0.45-1.12 ng mL-1, respectively. The relative standard deviations were below 12%. The method was assessed for extracting PAHs from real samples including agricultural water, rainwater and spring water. The obtained relative recoveries were higher than 86%.

Application of reusable flat-membrane in electro-membrane extraction for tamsulosin hydrochloride determination in cleaning validation samples of sterile production line equipment by RP-HPLC.

In order to ensure compliance with the current Good Manufacturing Practice (cGMP), cleaning process of pharmaceutical manufacturers should be validated. This study was aimed to utilize a reusable flat-membrane in the electromembrane extraction (EME) for isolation of tamsulosin hydrochloride (TMS) from rinse samples of sterile production of pharmaceutical line. Moreover, validation of mentioned method was done. The residual concentration of TMS was determined by RP-HPLC. Effective parameters such as pH, applying voltage and extraction time were optimized individually. Optimum conditions were found 12, 100 V and 10 min for pH, applying voltage and extraction time, respectively. Figures of merit were calculated under optimum conditions, therefore, linear range and limit of detection (LOD) were obtained 0.5-1000 ng mL-1 with a good coefficient of determination (R2=0.9901) and 0.05 ng mL-1, respectively. Last but not least, RSD of determination was found 0.67% which shows a satisfactory repeatability. According to the obtained results, proposed method is a precise, accurate, relatively fast and applicable route to determine TMS concentrations in rinse samples.

A 96-Monolithic inorganic hollow fiber array as a new geometry for high throughput solid-phase microextraction of doxorubicin in water and human urine samples coupled with liquid chromatography-tandem mass spectrometry.

Innovations in extraction phases, extraction modes and hyphenated instrument configurations, are the most important issues to address for progress in the solid phase microextraction (SPME) methodology. In this regard, we have embarked on the development of a novel biocompatible 96-monolithic inorganic hollow fiber (96-MIHF) array as a new configuration for high-throughput SPME on a 96-well plate system. An arrangement of highly ordered 96 titania/Hydroxyapatite (TiO2/HAP) nanocomposite hollow fibers and corresponding stainless-steel needles on a Teflon plate holder were used as the extraction module. The inorganic hollow fibers were prepared via a rapid and reproducible template approach (Polypropylene hollow fiber) in combination with a sol-gel method in the presence of polyvinyl alcohol (PVA), as a network maker. The hollow fiber-shape sorbents were obtained with excellent precision by weight (RSD% = 4.98, n = 10) and length (RSD% = 1.08, n = 10) criteria. The proposed design can overcome a number of geometrically dependent drawbacks of conventional high-throughput SPME methods, mainly the ones related to sorbent amount and surface area due to possessing inner/outer surfaces without additional internal supports. The SPME platform, for the first time, was successfully applied for the extraction and preconcentration of doxorubicin from urine and water media without requiring sample preparation and free from significant matrix effect. The extracted analyte was analyzed by liquid chromatography-ion trap tandem mass spectrometry (LC-MS/MS). Highly satisfactory analytical figures of merit were obtained under optimized conditions. The limit of detection (LOD), limit of quantification (LOQ) and linearity of determination were 0.1 ng mL-1, 0.25 ng mL-1 and 0.25 to 4000 ng mL-1, respectively. The interday, intraday and inter sorbent precisions for three concentration levels ranged from 2.01 to 8.09 % (n = 3), 1.02 to 8.65 % (n = 5) and 0.99 to 1.02% (n = 15), respectively. The mean intra-well RSD value for 96 individual wells in 96-MIHF-SPME-LC-MS/MS (n = 3) at the medium concentration level was 7.81%.

Haas in grilled meat: Determination using an advanced lab-on-a-chip flat electromembrane extraction coupled with on-line HPLC.

In this research, a new design of channels in a lab-on-a-chip device with flat electromembrane extraction (LOC-FLEME) was fabricated. The latter microfluidic device was successfully used for the determination of 2-amino-3-methyl imidazo[4-5-f]quinolone (IQ), 2-amino-3, 8-dimethlylimidazo[4, 5-f]quinolone (MeIQ), 2-amino-3,4- dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-1-methyl-6-phenylimidazo[4, 5-b] pyridine (PhIP) in grilled meat, by on-line coupling of LOC-FLEME to an HPLC system. Important parameters in extraction process were optimized. The calibration curve was linear over the range of 5-1000 ng g-1 with a correlation coefficient higher than 0.9991. The relative recoveries were between 95 and 98% at three concentration levels. The relative standard deviations were 4.1 to 6.0%. The limits of detection were 1.4, 0.9, 1.7 and 1.3 ng g-1 for PhIP, IQ, MeIQ and MeIQx, respectively. Sums of 4HAAs concentrations for different grilled meat samples were 2.75-6.17 ng g-1.

An improvement of electrospun membrane reusability via titanium dioxide nanoparticles and silane compounds for the electromembrane extraction.

A polyacrylonitrile (PAN)/polydimethylsiloxane (PDMS) flat membrane was fabricated by electrospinning technique and modified using titanium dioxide (TiO2) nanoparticles and low-energy materials, dimethyldichlorosilane (MeSiCl2)/methyltrichlorosilane (MeSiCl3), to obtain a hydrophobic surface. The new membrane was utilized for the electromembrane extraction (EME) of model molecules including dibutyl phthalate (DBP) and bis [2-ethylhexyl] phthalate (DEHP). The parameters affecting proposed EME were optimized by the response surface methodology (RSM) based on the central composite design (CCD). The optimized values were 200 V of voltage, 20 min of extraction time, 1100 rpm of agitation rate, 10 mL of donor phase volume and 1 mL of acceptor phase volume. From the results, the performance of EME with the new (modified) membrane remained almost constant after ten extraction cycles while the extraction performance of unmodified EME steeply fell after six extraction cycles. The limits of detection (LODs) for DBP and DEHP were 7.40 and 0.08 ng mL-1, respectively. The linear dynamic range (LDR) was in the range of 100-4000 ng mL-1 for DBP and 1-2000 ng mL-1 for DEHP. The relative standard deviations (RSDs) were below 10%, and the relative recoveries were over 86%. The overall energy consumption for the extraction of the model molecules by new EME was 13.4 kWh m-3. The approach is time-efficient and cost-effective, as the fabricated membrane has better reusability than the previous membranes used for EME.

Central Composite Design for Dispersive Liquid-liquid Microextraction of 25-hydroxy-cholecalciferol in Human Serum.

The human body's vitamin D levels are determined by measuring the level of 25-hydroxy-vitamin D3 (25-OH-vitamin D3) in human serum. In this research, a fast, simple, efficient and highly sensitive low-density solvent based on dispersive liquid-liquid microextraction (DLLME) was employed for the successful determination of 25-OH-vitamin D3 from complex human serum matrices. Reversed phase high-performance liquid chromatography was used as a powerful technique. The important parameters in the low-density solvent-DLLME method were optimized using response surface methodology based on central composite design. The calibration curves displayed a high level of linearity (R2 > 0.997) for 25-OH-vitamin D3 in the range of 2-500 ng mL-1. The limit of detection and limit of quantitation were 0.6 ng mL-1 and 1.9 ng mL-1, respectively. The relative standard deviation for the seven analyses was 7.1%. The relative recoveries of vitamin D3 in spiked human serum samples were between 85% and 97%. The amount of 25-OH-vitamin D3 in samples was determined using the proposed method and acceptable results were reported.

Electrospun polydimethylsiloxane/polyacrylonitrile/titanium dioxide nanofibers as a new coating for determination of alpha-linolenic acid in milk by direct immersion-solid phase nanoextraction.

In this study, polydimethylsiloxane/polyacrylonitrile/titanium dioxide (PDMS/PAN/TiO2) nanofibers were synthesized via electrospinning method to extract and quantify alpha-linolenic acid (ALA, C18:3), as a model analyte, in milk by direct immersion-solid phase nanoextraction (DI-SPNE) with gas chromatography-flame ionization detector (GC-FID). The affecting factors on the electrospinning process such as, PDMS concentration, amount of TiO2 nanoparticles (NPs), voltage, and electrospinning distance were optimized using Taguchi's orthogonal design. The SPNE experimental conditions such as, extraction time, agitation rate, pH and salt concentration, were also optimized using response surface methodology (RSM) based on a central composite design (CCD). Under optimized conditions, the resulting calibration curve was linear in the range of 1-4000ngmL-1 with R2=0.998. The intraday, interday, and fiber-to-fiber repeatability were calculated and the corresponding relative standard deviation was less than 9% in all the cases. The limit of detection and limit of quantification were found to be 0.2 and 0.6ngmL-1, respectively. Omega-3 enriched milk was used as a real sample and the value of relative recoveries were measured to be in the range of 92-106%.

Zeolite/Fe3O4 as a new sorbent in magnetic solid-phase extraction followed by gas chromatography for determining phthalates in aqueous samples.

In the present study, for the first time, we successfully employed zeolite/Fe3O4 as a new magnetic nanoparticle sorbent in magnetic solid-phase extraction for determining phthalates in aqueous samples. Gas chromatography with flame ionization detection was used to detect the target analytes as a powerful instrumental analysis. Affecting parameters in the extraction process, including the amount of adsorbent, adsorption and desorption time, and volume of desorption solvent, were optimized using a response surface methodology based on central composite design. Under the optimum conditions, the linear range for dibutyl phthalate and bis(2-ethylhexyl phthalate) was varied in the interval of 10-1700 and 10-1200 µg/L, respectively. Limits of detection were 2.80 µg/L for dibutyl phthalate and 3.20 µg/L for bis(2-ethylhexyl phthalate). The recovery value for the extraction of target analytes was between 97 and 111%. The repeatability and reproducibility of the new proposed method were obtained: 10-13% and 13-13.5%, respectively. The increased sensitivity in using the proposed method has been demonstrated. Compared with previous methods, the new proposed method is an accurate, rapid, and reliable sample-pretreatment method.