Simultaneous determination of blockers and agonists by on-fiber derivatization in self-made solid-phase microextraction coating fiber

Ultrasensitive Eu-Based MOF Luminescence Sensor for Clenbuterol Visible Recognition

Clenbuterol (CLB) as an illegal feed additive may cause a great security risk to food safety. However, convenient and efficient detection means for CLB in practical application remain a formidable challenge. Herein, a stable Eu-based organic framework {[H2N(CH3)2]2[Eu2(ttca)2]·H2O}n (compound 1) (H4ttca = [1,1':2',1″-terphenyl]-4,4',4″,5'-tetracarboxylic acid) has been harvested, exhibiting excellent chemical stability and thermal stability. Luminescence investigation reveals that compound 1 can sensitively and selectively detect CLB without being affected by different components from simulated serum and urine (limit detection: 22.7 nM). Furthermore, sensor 1 can also be applicable to CLB recognition in real swine feeds, presenting excellent anti-interference performance. The good cyclicity of compound 1 endows CLB determination with many advantages: low cost, high stability, and simplicity. Importantly, in view of the indication of the luminescence color (red to blue), test membranes were fabricated and employed for convenient and fast CLB detection, providing a valuable scheme for the visual monitoring of CLB in meat products. This work enriches rare earth metal compounds and luminescence sensor portfolios and breaks the concentration record (nM) for detecting CLB compared with reported complex materials, providing an effective monitoring platform for CLB visually.

MXene nanosheets woven in polyacrylonitrile nanofiber yarns aligned spider web as a highly efficient sorbent for in-tube solid phase microextraction of beta-blockers from biofluids

The use of electrospinning has received much attention in the production of nanofiber webs due to its advantages such as flexibility and simplicity. The direct electrospinning of nanofibers in an aligned or twisted form and the production of nanofiber yarns can turn nanofibers into woven fabrics, which leads to an increase in the diversity of nanofiber applications and improves their end-use possibilities. In this work, a victorious nanofiber yarn spinning system was used with the help of a rotating funnel. Yarn formation was studied using a composited polyacrylonitrile (PAN)/MXene polymer solution ejected from two oppositely charged nozzles. Finaly their application for packed-in-tube solid-phase microextraction of β-blocker drugs from biofluids was demonstrated. The separation and quantification of analytes were performed by HPLC-UV instrument. The 3D-yarn PAN/MXene sorbent exhibited high flexibility, porosity, sorbent loading, mechanical stability, and a long lifetime. The characterization of the final nanofiber was carried out utilizing Fourier-transform infrared spectroscopy, field emission scanning electron microscope, energy-dispersive X-ray mapping, transmission electron microscope and X-ray diffraction analysis. Various parameters that affect the extraction efficiency, such as extraction time, pH, ionic strength and flow rate of sample solution, and type, volume and flow rate of eluent, were investigated and optimized. Under optimized conditions, the limits of detection were obtained in the range of 1.5-3.0 μg L-1. This method demonstrated appropriate linearity for β-blockers in the range of 5.0-1000.0 μg L-1, with coefficients of determination greater than 0.990. The inter- and intra-assay precisions (RSDs, for n = 3) are in the range of 2.5-3.5%, and 4.5-5.2%, respectively. Finally, the validated method was put in an application for the analysis of atenolol, propranolol and betaxolol in human urine and saliva samples at different hours and acceptable relative recoveries were obtained in the range of 89.5% to 110.4%.

Application of MIL-53(Al) prepared from waste materials for solid-phase microextraction of propranolol followed by corona discharge-ion mobility spectrometry (CD-IMS)

In this study, MIL-53(Al) metal-organic framework was prepared from waste raw materials. A polyethylene terephthalate (PET) plastic bottle was used as the source of terephthalic acid, and an aluminium beverage can was applied as the precursor of aluminium salt. The activated MIL-53(Al) was immobilized onto a stainless steel probe of the ion mobility spectrometer (IMS), and the coated probe was used for solid-phase microextraction of propranolol from biological samples before determination. The effect of the different parameters such as pH, ionic strength, and stirring rate of the sample, extraction time, and temperature was studied on the extraction efficiency of propranolol. The linearity was obtained ranging from 5-200 μg L^-1 with a determination coefficient (R²) of 0.9988, and the detection limit was calculated 1.7 μg L^-1 in the water sample. The relative standard deviations of the method were in the range of 2.5-12.2 %. Finally, the method was utilized for determination of propranolol in the tablet sample.

Miniaturized sample preparation methods for saliva analysis

Saliva, as the first body fluid encountering with the exogenous materials, has good correlation with blood and plays an important role in bioanalysis. However, saliva has not been studied as much as the other biological fluids mainly due to restricted access to its large volumes. In recent years, there is a growing interest for saliva analysis owing to the emergence of miniaturized sample preparation methods. The purpose of this paper is to review all microextraction methods and their principles of operation. In the following, we examine the methods used to analyze saliva up to now and discuss the potential of the other microextraction methods for saliva analysis to encourage research groups for more focus on this important subject area.

Ultrasound-promoted dispersive micro solid-phase extraction of trace anti-hypertensive drugs from biological matrices using a sonochemically synthesized conductive polymer nanocomposite

In this work, a rapid and efficient procedure named ultrasound meliorated dispersive micro solid-phase extraction followed by high performance liquid chromatography-ultra violet detection (US-D-μSPE-HPLC-UV) was developed for the pre-concentration of the main trace anti-hypertensive drugs in complex matrices. The basis of this procedure was a polypyrrole-sodium dodecylbenzenesulfonate/zinc oxide (PPy-DBSNa/ZnO) nanocomposite. It was readily synthesized by the impressive way of in situ sonochemical oxidative polymerization in the presence of some additives such as FeCl₃ and DBSNa, ultimately leading to the effective coating of PPy on the ZnO nanoparticle cores. Characterization of the proposed nanosorbent was performed by different techniques such as FESEM, XRD,EDX, and TGA, confirming the high quality and proper physico-chemical properties of the proposed sorbent. In order to better investigate the input variables, the central composite design (CCD) combined with the desirability function (DF) was utilized. The enriched optimum conditions consisted of the initial pH value of 11.8, 15mg of the PPy-DBSNa/ZnO nanocomposite, a sonication time of 4.6min, and 100μL of methanol, resulting in maximum responses at a relatively low extraction time with a logical DF. Under the optimum conditions, good linearity (5-5000, 2.5-3500, and 2.5-3000ngmL^-1 for metoprolol, propranolol, and carvedilol, respectively, with the correlation of determinations (R²s) higher than 0.99), low limits of detection (LODs) (0.8-1.5ngmL^-1), proper repeatabilities (relative standard deviation values (RSDs) below 6.3%, n=3), reasonable enrichment factors (EFs) (60-72), and good extraction recoveries (ERs) (higher than %75) were obtainable. These appropriate validations corroborated a good effectiveness of ultrasonic waves in the achievement of a supreme solid phase as well as a facile and efficient microextraction of the low therapeutic concentrations in human plasma and urine samples.

1-Butyl-3-aminopropyl imidazolium-functionalized graphene oxide as a nanoadsorbent for the simultaneous extraction of steroids and β-blockers via dispersive solid-phase microextraction

In this study, we describe the synthesis of graphene oxide functionalized with the ionic liquid 1-butyl-3-aminopropyl imidazolium chloride and its use as an adsorbent for the dispersive solid-phase microextraction (micro SPE) of four anabolic steroids and six β-blockers from aqueous samples of environmental importance, prior to their HPLC-diode array detector analysis. As the ionic liquid is covalently attached to graphene oxide sheets, it is made possible for it to participate in the dispersive micro SPE procedure. The limits of detection and limits of quantification of the proposed method were found to be in the range of 7-23ng/L and between 20 and 70ng/L, respectively. The linearity was satisfactory, with the determination coefficients to range from 0.9940 to 0.9998 while the within- and between-day relative standard deviation of the method ranged between 3.1 and 7.6% and from 4.0 to 8.5%, respectively. In order to test the applicability of the proposed method in real-life samples, the effluent from a municipal wastewater treatment plant as well as natural water samples from two rivers and a lake were collected and analyzed. After the analysis of samples, the effluent from municipal wastewater treatment plant was fortified with the analytes, at concentrations equal to 2 and 10 times the LOQs. Recoveries were calculated after subtracting the native (no-spike) concentrations of analytes, when needed. All the recoveries were in the range of 87-98%. A comparison study attests to the superiority of the developed nanomaterial over graphene oxide and graphene for the dispersive micro SPE of steroids and β-blockers.