In-line carbon nanofiber reinforced hollow fiber-mediated liquid phase microextraction using a 3D printed extraction platform as a front end to liquid chromatography for automatic sample preparation and analysis: A proof of concept study

Implications of analytical nanoscience in pharmaceutical and biomedical fields: A critical view

This review summarizes recent progress performed in the design and application of analytical tools and methodologies using nanomaterials for pharmaceutical analysis, and specifically new nanomedicines at distinct phases of development and translation from preclinical to clinical stages. Over the last 10-15 years, a growing number of studies have utilized various nanomaterials, including carbon-based, metallic nanoparticles, polymeric nanomaterials, materials based on biological molecules, and composite nanomaterials as tools for improving the analysis of pharmaceutical products. New and more complex nanomaterials are currently being explored to influence different stages of the analytical process. These materials provide unique properties to support the extraction of analytes in complex samples, increase the selectivity and efficiency of chromatographic separations, and improve the analytical properties of many sensor applications. Indeed, nanomaterials, including electrochemical detection approaches and biosensing, are expanding at a remarkable rate. Furthermore, the analytical performance of numerous approaches to determine drugs in different matrices can be significantly improved in terms of precision, detection limits, selectivity, and time of analysis. However, the quality control and metrological characterization of the currently synthesized nanomaterials still depend on the development of new and improved analytical methodologies, and the application of specific and improved instrumentation. Therefore, there is still much to explore about the properties of nanomaterials which need to be determined even more precisely and accurately.

Hierarchical porous zeolitic imidazolate framework‑8 supported hollow-fiber liquid-phase microextraction of nine typical phenolic pollutants in water samples followed by electrophoretic analysis

Hierarchical porous zeolitic imidazolate framework‑8 (HpZIF-8) have not only good chemical and thermal stability, but also pore structures of different sizes. In this work, HpZIF-8 supported hollow-fiber liquid-phase microextraction (HpZIF-8@HF-LPME) co-modified with tributyl phosphate and 2-nitroethyl benzene was firstly developed for purification and enrichment of nine typical phenolic pollutants followed by electrophoretic separation and amperometric detection (CE-AD). The key enrichment parameters were optimized by full factorial experimental and central composite designs. Under the optimum conditions, the maximum enrichment factors for the nine analytes were 479 (phenol), 249 (2-chlorophenol), 821 (4-chlorophenol), 1253 (3-methylphenol), 1376 (2,4-dichlorophenol), 1078 (2,4,6-trichlorophenol), 200 (pentachlorophenol), 614 (4-nitrophenol) and1827 times (bisphenol A), respectively. The limits of detection were 0.060-1.5 µg L-1 (S/N = 3) in real sample matrixes. This proposed method has been successfully applied to water samples with high ionic strength, and the average recoveries were in the range of 80.2-118.0%. This developed method of HpZIF-8@HF-LPME/CE-AD needs no desorption and derivatization, providing an alternative for monitoring typical phenolic pollutants in water samples.

Carrasco-Correa E, Varanasupakul P, Kubáň P, Miró M. Programmable Millifluidic Platform Integrating Automatic Electromembrane Extraction Cleanup and In-Line Electrochemical Detection: A Proof of Concept

A fully automatic millifluidic sensing platform coupling in-line nonsupported microelectromembrane extraction (μ-EME) with electrochemical detection (ECD) is herein proposed for the first time. Exploiting the features of the second generation of flow analysis, termed sequential injection (SI), the smart integration of SI and μ-EME-ECD enables (i) the repeatable formation of microvolumes of phases for the extraction step in a membrane-less (nonsupported) arrangement, (ii) diverting the acceptor plug to the ECD sensing device, (iii) in-line pH adjustment before the detection step, and (iv) washing of the platform for efficient removal of remnants of wetting film solvent, all entirely unsupervised. The real-life applicability of the miniaturized sensing system is studied for in-line sample cleanup and ECD of diclofenac as a model analyte after μ-EME of urine as a complex biological sample. A comprehensive study of the merits and the limitations of μ-EME solvents on ECD is presented. Under the optimal experimental conditions using 14 μL of unprocessed urine as the donor, 14 μL of 1-nonanol as the organic phase, and 14 μL of 25 mM NaOH as the acceptor in a 2.4 mm ID PTFE tubing, an extraction voltage of 250 V, and an extraction time of 10 min, an absolute (mass) extraction recovery of 48% of diclofenac in urine is obtained. The proposed flow-through system is proven to efficiently remove the interfering effect of predominantly occurring organic species in human urine on ECD with RSD% less than 8.6%.

At-line coupling of hollow fiber liquid-phase microextraction to capillary electrophoresis for trace determination of acidic drugs in complex samples

Direct analysis of complex samples is demonstrated by the at-line coupling of hollow fiber liquid-phase microextraction (HF-LPME) to capillary electrophoresis (CE). The hyphenation of the preparative and the analytical technique is achieved through a 3D-printed microextraction device with an HF located in a sample vial of a commercial CE instrument. The internal geometry of the device guides the CE separation capillary into the HF and the CE injection of the HF-LPME extract is performed directly from the HF lumen. The 3D-printing process ensures uniform dimensions of the devices, their constant position inside the sample vial, and excellent repeatability of the HF-LPME as well as the CE injection. The devices are cheap (∼0.01 €) and disposable, thus eliminating any possible sample-carryover, moreover, the at-line CE analysis of the extract is performed fully autonomously with no need for operator's intervention. The developed HF-LPME/CE-UV method is applied to the determination of acidic drugs in dried blood spot and wastewater samples and is characterized by excellent repeatability (RSD, 0.6-9.6%), linearity (r², 0.9991-0.9999), enrichment (EF, 29-97), sensitivity (LOD, 0.2-3.4 μg/L), and sample throughput (7 samples/h). A further improvement of selected characteristics of the analytical method is achieved by the at-line coupling of HF-LPME to capillary isotachophoresis (ITP) with electrospray ionization-mass spectrometry (ESI-MS). The HF-LPME/ITP-ESI-MS system facilitates enhanced selectivity, matrix-free analytical signals, and up to 34-fold better sensitivity due to the use of ESI-MS detection and additional on-capillary ITP preconcentration of the HF-LPME extracts.

Miniaturized green sample preparation approaches for pharmaceutical analysis

The development of green sample preparation procedures is an extremely important research field in which more and more applications are constantly being proposed in different areas, including pharmaceutical analysis. This review article is aimed at providing a general overview of the development of miniaturized green analytical sample preparation procedures in the pharmaceutical analysis field, with special focus on the works published between January 2017 and July 2021. Particular attention has been paid to the application of environmentally friendly solvents and sorbents as well as nanomaterials or high extraction capacity sorbents in which the solvent volumes and reagents amounts are drastically reduced, with their subsequent advantages from the sustainability point of view.

Recent progress of microfluidic technology for pharmaceutical analysis

In recent years, the progress of microfluidic technology has provided new tools for pharmaceutical analysis and the proposal of pharm-lab-on-a-chip is appealing for its great potential to integrate pharmaceutical test and pharmacological test in a single chip system. Here, we summarize and highlight recent advances of chip-based principles, techniques and devices for pharmaceutical test and pharmacological/toxicological test focusing on the separation and analysis of drug molecules on a chip and the construction of pharmacological models on a chip as well as their demonstrative applications in quality control, drug screening and precision medicine. The trend and challenge of microfluidic technology for pharmaceutical analysis are also discussed and prospected. We hope this review would update the insight and development of pharm-lab-on-a-chip.

4D-Printed Temperature-Controlled Flow-Actuated Solid-Phase Extraction Devices

Four-dimensional printing (4DP) technologies can extend the functionality and applicability of manufactured analytical devices through employing stimuli-responsive materials. In this study, we used a photocurable resin of stimuli-responsive shape-memory polymers and digital light processing three-dimensional printing (3DP) to fabricate a smart sample pretreatment device featuring a solid-phase extraction (SPE) column and a temperature-controlled flow-actuated valve. Through manipulation of the temperatures and flow rates of the sample, eluent, and rinsing streams, we used this 4D-printed SPE device to extract Mn, Co, Ni, Cu, Zn, Cd, and Pb ions from high-salt content samples and remove the sample matrix prior to their determination by inductively coupled plasma mass spectrometry. After optimizing the valve design and operation and the analytical scheme, this device displayed competitive analytical performance-the method detection limits (MDLs) ranged from 0.7 to 22.1 ng L^-1 for these metal ions (the MDLs ranged from 0.5 to 18.8 ng L^-1 when validating the same printed SPE column using an online automatic system equipped with electric switching valves). Furthermore, we performed analyses of these metal ions in three reference materials (CASS-4, 1643f, and 2670a) and spike analyses of collected samples (seawater, ground water, river water, and human urine) to confirm the reliability and applicability of this analytical method. For the first time, 4DP has been used to fabricate a multi-functional, stimuli-responsive sample pretreatment device displaying analytical performance equal to that of a commercial apparatus. This novel approach builds upon the functionality and diversity of 3DP-enabling devices with the goal of developing more efficient analytical schemes.

3D printed device for epitachophoresis

Polyacrylamide or agarose gels are the most frequently used sieving and stabilizing media in slab gel electrophoresis. Recently, we have introduced a new electrophoretic technique for concentration/separation of milliliter sample volumes. In this technique, the gel is used primarily as an anticonvection media eliminating liquid flow during the electromigration. While serving well for the liquid stabilization, the gels can undergo deformation when exposed to a discontinuous electrolyte buffer system used in epitachophoresis. In this work, we have explored 3D printing to form rigid stabilizing manifolds to minimize liquid flow during the epitachophoresis run. The whole device was printed using the stereolithography technique from a low water-absorbing resin. The stabilizing manifold, serving as the gel substitute, was printed as a replaceable composite structure preventing electrolyte mixing during the separation. Different geometries of the 3D printed stabilizing manifolds were tested for use in concentrating ionic sample components without spatial separation. The presented device can focus analytes from 3 or 4 mL of the sample to 150 μL or less, depending on the collection cup size. With the 150 μL collection cup, this represents the enrichment factor from 20 to 27. The time of concentration was from 15 to 25 min, depending on stabilization media and power used.

Low-cost and open-source strategies for chemical separations

In recent years, a trend toward utilizing open access resources for laboratory research has begun. Open-source design strategies for scientific hardware rely upon the use of widely available parts, especially those that can be directly printed using additive manufacturing techniques and electronic components that can be connected to low-cost microcontrollers. Open-source software eliminates the need for expensive commercial licenses and provides the opportunity to design programs for specific needs. In this review, the impact of the "open-source movement" within the field of chemical separations is described, primarily through a comprehensive look at research in this area over the past five years. Topics that are covered include general laboratory equipment, sample preparation techniques, separations-based analysis, detection strategies, electronic system control, and software for data processing. Remaining hurdles and possible opportunities for further adoption of open-source approaches in the context of these separations-related topics are also discussed.

Zeolitic imidazolate framework-8 reinforced hollow-fiber liquid-phase microextraction of free urinary biomarkers of whole grain intake followed by CE analysis

The whole grain intake is closely associated with human health. In this work, three-phase dynamic hollow-fiber liquid-phase microextraction reinforced with 0.10 mg/mL 30 nm zeolitic imidazolate framework-8 nanoparticles was introduced for purification and enrichment of free urinary metabolite biomarkers of whole grain intake. Eight milliliters of HCl (pH 3.00) and 8 μL of 300 mM NaOH solutions were used as the donor and acceptor phases, respectively. The temperature and stirring rate were kept at 25℃ and 500 rpm, and the extraction time was 40 min. The extraction process required no further desorption, and the resultant extract was directly used for electrophoretic analysis without derivatization. Based on the synergistic effect of hollow-fiber liquid-phase microextraction and the electrophoretic stacking, the enrichment factors of 3,5-dihydroxybenzoic acid and 3-(3,5-dihydroxyphenyl)-1-propionic acid reached 1018-1034 times, and their limits of detection achieved 0.33-0.67 ng/mL (S/N = 3) in urine matrix. The developed method has been successfully used for urine analysis, and the sample recovery data were in the range of 97.0-103.5%. This developed method provided an attractive alternative for the determination of urinary metabolite biomarkers of whole grain intake due to its sensitive, fast, low-cost, and environmental-friendly features.

Hollow fiber-based liquid phase microextraction followed by analytical instrumental techniques for quantitative analysis of heavy metal ions and pharmaceuticals

Hollow-fiber liquid-phase microextraction (HF-LPME) and electromembrane extraction (EME) are miniaturized extraction techniques, and have been coupled with various analytical instruments for trace analysis of heavy metals, drugs and other organic compounds, in recent years. HF-LPME and EME provide high selectivity, efficient sample cleanup and enrichment, and reduce the consumption of organic solvents to a few micro-liters per sample. HF-LPME and EME are compatible with different analytical instruments for chromatography, electrophoresis, atomic spectroscopy, mass spectrometry, and electrochemical detection. HF-LPME and EME have gained significant popularity during the recent years. This review focuses on hollow fiber based techniques (especially HF-LPME and EME) of heavy metals and pharmaceuticals (published 2017 to May 2019), and their combinations with atomic spectroscopy, UV-VIS spectrophotometry, high performance liquid chromatography, gas chromatography, capillary electrophoresis, and voltammetry.

3D Printing in analytical sample preparation

In the last 5 years, additive manufacturing (three-dimensional printing) has emerged as a highly valuable technology to advance the field of analytical sample preparation. Three-dimensional printing enabled the cost-effective and rapid fabrication of devices for sample preparation, especially in flow-based mode, opening new possibilities for the development of automated analytical methods. Recent advances involve membrane-based three-dimensional printed separation devices fabricated by print-pause-print and multi-material three-dimensional printing, or improved three-dimensional printed holders for solid-phase extraction containing sorbent bead packings, extraction disks, fibers, and magnetic particles. Other recent developments rely on the direct three-dimensional printing of extraction sorbents, the functionalization of commercial three-dimensional printable resins, or the coating of three-dimensional printed devices with functional micro/nanomaterials. In addition, improved devices for liquid-liquid extraction such as extraction chambers, or phase separators are opening new possibilities for analytical method development combined with high-performance liquid chromatography. The present review outlines the current state-of-the-art of three-dimensional printing in analytical sample preparation.

Microextraction approaches for bioanalytical applications: An overview

Biological samples are usually complex matrices due to the presence of proteins, salts and a variety of organic compounds with chemical properties similar to those of the target analytes. Therefore, sample preparation is often mandatory in order to isolate the analytes from troublesome matrices before instrumental analysis. Because the number of samples in drug development, doping analysis, forensic science, toxicological analysis, and preclinical and clinical assays is steadily increasing, novel high throughput sample preparation approaches are calling for. The key factors in this development are the miniaturization and the automation of the sample preparation approaches so as to cope with most of the twelve principles of green chemistry. In this review, recent trends in sample preparation and novel strategies will be discussed in detail with particular focus on sorptive and liquid-phase microextraction in bioanalysis. The actual applicability of selective sorbents is also considered. Additionally, the role of 3D printing in microextraction for bioanalytical methods will be pinpointed.

Multi-walled Carbon Nanotubes Reinforced into Hollow Fiber by Chitosan Sol-gel for Solid/Liquid Phase Microextraction of NSAIDs from Urine Prior to HPLC-DAD Analysis

Background:

The efficient analytical method for the analysis of nonsteroidal antiinflammatory drugs (NSAIDs) in a biological fluid is important for determining the toxicological aspects of such long-term used therapies.

Methods:

In the present work, multi-walled carbon nanotubes reinforced into a hollow fiber by chitosan sol-gel assisted-solid/ liquid phase microextraction (MWCNTs-HF-CA-SPME) method followed by the high-performance liquid chromatography-diode array detection (HPLC–DAD) was developed for the determination of three NSAIDs, ketoprofen, diclofenac, and ibuprofen in human urine samples. MWCNTs with various dimensions were characterized by various analytical techniques. The extraction device was prepared by immobilizing the MWCNTs in the pores of 2.5 cm microtube via chitosan sol-gel assisted technology while the lumen of the microtube was filled with few microliters of 1-octanol with two ends sealed. The extraction device was operated by direct immersion in the sample solution.

Results:

The main factors influencing the extraction efficiency of the selected NSAIDs have been examined. The method showed good linearity R2 ≥ 0.997 with RSDs from 1.1 to 12.3%. The limits of detection (LODs) were 2.633, 2.035 and 2.386 µg L-1, for ketoprofen, diclofenac, and ibuprofen, respectively. The developed method demonstrated a satisfactory result for the determination of selected drugs in patient urine samples and comparable results against reference methods.

Conclusion:

The method is simple, sensitive and can be considered as an alternative for clinical laboratory analysis of selected drugs.