Miniaturized 3D printed solid-phase extraction cartridges with integrated porous frits.

Here we have studied the effect of the thickness and printing orientation using PolyJet 3D printing to fabricate single-material cartridges with built-in porous frits enabling solid-phase extraction (SPE) by packing commercial sorbents. This is achieved by tuning the degree of interpenetration of the building material and the water-soluble support material used in PolyJet 3D printing by modifying the orientation of the print head respective to the frit. SPE cartridges printed at an orientation of 30° with a 150 µm thick integrated frit were selected for the SPE experiments in a compromise between frit permeability to flow and stability to retain commercial sorbents for SPE. The performance of the 3D printed cartridges was evaluated for the SPE of the endocrine-disrupting phenols 4-tert-octylphenol (4-tOP) and 4-nonylphenol (4-NP), comparing three commercial SPE sorbents (Evolute Express ABN, Bond Elut PPL, and Silica-C18). The best overall extraction performance was obtained using Silica-C18, and the main extraction parameters were optimized. Detection limits of 0.3 µg L-1 for 4-tOP and 1.1 µg L-1 for 4-NP were achieved using HPLC-DAD for analyte separation and quantification. Enrichment factors of 30.1 (4-tOP) and 16.2 (4-NP) were obtained under the selected conditions. The developed method was applied to water and milk powder samples obtaining satisfactory recoveries ranging from 97% to 103%. These results demonstrate the suitability of PolyJet 3D printing for the fabrication of miniaturized cartridges with integrated frits for SPE applications.

Optimization of smartphone-based on-site-capable uranium analysis in water using a 3D printed microdevice.

Recent development of portable three-dimensional printed (3DP) microfluidic-based devices has provided a new horizon for real-time field analysis of environmental pollutants. Smartphones with the possibility of launching different software, sensing, and grading color intensity, as well as capability of sending/receiving data through the internet have made this technology very promising. Here, a novel smartphone-based 3DP microfluidic device is reported that uses an image-based colorimetric detection method for the analysis of uranium in water samples, based on the complex formation of uranyl ions with Arsenazo III. The microfluidic device consists of two horizontal channels, separated by an integrated porous membrane, and was printed in a single run using a transparent photopolymer. It enables the operator to see the internal parts and the color change visually, as well as enables the operator to take images and record the color intensity using a smartphone. In each 3DP run, 220 devices are fabricated in 1.5 h (~ 25 s per device) at an estimated price of $2.5 per device. A Box-Behnken design (BBD) was utilized for the optimization of experimental conditions. The calibration curve was linear within 0.5-100 µg mL-1 (R2 > 0.9925) of uranium analysis. The total time of each experiment was approximately 8 min. The 3DP device was successfully employed for the recovery and determination of uranium in spiked natural water samples.

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.

Stirring time effect of silver nanoparticles prepared in glutathione mediated by green method.

BACKGROUND: This study aims to investigate the influence of different stirring time for synthesis of silver nanoparticles in glutathione (GSH) aqueous solution. The silver nanoparticles (Ag-NPs) were prepared by green synthesis method using GSH as reducing agent and stabilizer, under moderate temperature at different stirring times. Silver nitrate (AgNO3) was taken as the metal precursor while Ag-NPs were prepared in the over reaction time. RESULTS: Formation of Ag-NPs was determined by UV-vis spectroscopy where surface plasmon absorption maxima can be observed at 344-354 nm from the UV-vis spectrum. The synthesized nanoparticles were also characterized by X-ray diffraction (XRD). The peaks in the XRD pattern confirmed that the Ag-NPs possessed a face-centered cubic and peaks of contaminated crystalline phases were unable to be located. Transmission electron microscopy (TEM) revealed that Ag-NPs synthesized were in spherical shape. Zeta potential results indicate that the stability of the Ag-NPs is increases at the 72 h stirring time of reaction comparison to GSH. The Fourier transform infrared (FT-IR) spectrum suggested the complexation present between GSH and Ag-NPs. The use of green chemistry reagents, such as peptide, provides green and economic features to this work. CONCLUSIONS: Ag-NPs were successfully synthesized in GSH aqueous solution under moderate temperature at different stirring times. The study clearly showed that the Ag-NPs synthesized in the long times of stirring, thus, the kinetic of GSH reaction is very slow. TEM results shows that with the increase of stirring times the mean particle size of Ag-NPs become increases. The FT-IR spectrum suggested the complexation present between GSH and Ag-NPs. These suggest that Ag-NPs can be employed as an effective bacteria inhibitor and can be applied in medical field.