An investigation of aspects of radiochemical purity of 99mTc-labelled human serum albumin nanocolloid

Background Nanocolloidal human serum albumin radiolabelled with 99mTc provides a diagnostic radiopharmaceutical for sentinel node lymphoscintigraphy. NanoHSA (Nanotop), a commercially available kit, enables the simple preparation of this radiopharmaceutical via reconstitution with pertechnetate eluted from a generator. Thin-layer chromatography is widely used for determining radiochemical purity in clinical nuclear medicine. Quality control methods recommended by the manufacturer were sometimes reported to yield variable results. Therefore, we proposed and evaluated three alternative thin-layer chromatography methods for the quality control of [99mTc]Tc-NanoHSA from a commercially available kit. Results The radiochemical purity of [99mTc]Tc-NanoHSA determined with all methods was reproducible and met the requirements of the SPC and the European Pharmacopoeia (≥ 95%). Our quality control using iTLC-SG chromatographic paper in methyl ethyl ketone mobile phase identified only free pertechnetate as impurity, resulting in > 99% RCP. The quality control using iTLC-SG in 85% methanol or iTLC-SA in 0.9% NaCl identified an additional small fraction of a hydrophilic impurity, resulting in 95–97% RCP. Glucose was identified as a potential 99mTc-carrying hydrophilic species contributing to hydrophilic impurities. Conclusion Our quality control of [99mTc]Tc-NanoHSA with non-polar mobile phase tended to underestimate the amount of hydrophilic impurities, although without compromising the final quality of the radiopharmaceutical. Alternative TLC methods using aqueous mobile phases enabled a more accurate determination of hydrophilic impurities.

Development and evaluation of two different electronic tongues aiming to the discrimination of cutting agents found in cocaine seized samples

The screening and impurity profiling of drugs, like cocaine, is essential information that provides chemical and/or physical characterization to assist police agencies in understanding the trafficking and identifying drug origin. This work proposes to show the development and applications of two different electronic tongues (e-tongues) on the profiling study of cocaine seized samples. The developed intelligent devices' primary objective is the simple, quick, and remote cocaine classification samples based on the individual cutting agents added. The paper-based colorimetric sensor was fabricated in the lab using chromatographic paper as a substrate, wax printing to produce spot zones of reactions, a smartphone as image detection, and an editing image software to extract the chemical information through RBG values. The voltammetric e-tongue applied a boron-dopped diamond electrode to extract the cutting agents' electrochemical information through the square wave voltammetry (SWV) technique. In any case, both described sensors were coupled to chemometric tools for data analysis to construct the discrimination model. According to the objective, the unsupervised pattern recognition technique, Principal Component Analysis (PCA), was applied to test the capability of the device on individually discriminating the most common cutting agents of cocaine.

Combined Paper-Based Substrates for Electrochemical Detection of Copper Ions in Serum

<p>The electroanalytical field has exploited great advantages in using paper-based substrates, even if the word “paper” might be general. In fact, the mainly adopted paper-based substrates are often chromatographic and office ones. They are characterized by main features (and drawbacks): chromatographic paper is well-established for storing reagents/treating samples but the sensitivity compared to traditional screen-printed is lower (due to porosity), while office paper represents a sustainable alternative to plastic (with similar sensitivity) but its porosity is not enough to load reagents. To overcome the limitations that might arise due to the adoption of a type of individual paper-based substrate, herein we describe for the first time, the development of a 2D merged paper-based devices for electrochemical copper ions detection in serum. In this work we report a novel configuration to produce an integrated all-in-one electrochemical device, in which no additional working media has to be added by the end user and the sensitivity can be tuned by rapid pre-concentration on porous paper, with the advantage of making the platform adaptable to real matrix scenario. The novel architecture has been obtained by combining office paper to screen-print a sustainable and robust electrochemical strip, the printed electrochemical strips and chromatographic one to 1) store the reagents, 2) collect real sample and 3) pre-concentrate the analyte of interest. The novel sensing platform has allowed to obtain a detection limit for copper ions down to 5 ppb in all the solutions that have been interrogated, namely standard solution and serum, and a repeatability of ca. 10% has been obtained.</p>

Combined Paper-Based Substrates for Electrochemical Detection of Copper Ions in Serum

<p>The electroanalytical field has exploited great advantages in using paper-based substrates, even if the word “paper” might be general. In fact, the mainly adopted paper-based substrates are often chromatographic and office ones. They are characterized by main features (and drawbacks): chromatographic paper is well-established for storing reagents/treating samples but the sensitivity compared to traditional screen-printed is lower (due to porosity), while office paper represents a sustainable alternative to plastic (with similar sensitivity) but its porosity is not enough to load reagents. To overcome the limitations that might arise due to the adoption of a type of individual paper-based substrate, herein we describe for the first time, the development of a 2D merged paper-based devices for electrochemical copper ions detection in serum. In this work we report a novel configuration to produce an integrated all-in-one electrochemical device, in which no additional working media has to be added by the end user and the sensitivity can be tuned by rapid pre-concentration on porous paper, with the advantage of making the platform adaptable to real matrix scenario. The novel architecture has been obtained by combining office paper to screen-print a sustainable and robust electrochemical strip, the printed electrochemical strips and chromatographic one to 1) store the reagents, 2) collect real sample and 3) pre-concentrate the analyte of interest. The novel sensing platform has allowed to obtain a detection limit for copper ions down to 5 ppb in all the solutions that have been interrogated, namely standard solution and serum, and a repeatability of ca. 10% has been obtained.</p>

Silver Inkjet-Printed Electrode on Paper for Electrochemical Sensing of Paraquat

The use of fully printed electrochemical devices has gained more attention for the monitoring of clinical, food, and environmental analytes due to their low cost, great reproducibility, and versatility characteristics, serving as an important technology for commercial application. Therefore, a paper-based inkjet-printed electrochemical system is proposed as a cost-effective analytical detection tool for paraquat. Chromatographic paper was used as the printing substrate due its sustainable and disposable characteristics, and an inkjet-printing system deposited the conductive silver ink with no further modification on the paper surface, providing a three-electrode system. The printed electrodes were characterized with scanning electron microscopy, cyclic voltammetry, and chronopotentiometry. The proposed sensor exhibited a large surface area, providing a powerful tool for paraquat detection due to its higher analytical signal. For the detection of paraquat, square-wave voltammetry was used, and the results showed a linear response range of 3.0–100 μM and a detection limit of 0.80 µM, along with the high repeatability and disposability of the sensor. The prepared sensors were also sufficiently selective against interference, and high accuracy (recovery range = 96.7–113%) was obtained when applied to samples (water, human serum, and orange juice), showing the promising applicability of fully printed electrodes for electrochemical monitoring.

Chemical Selection for Flocculation of the Sludges Produced During Lime Neutralization of Acidic Spent Pickling Solutions and Rinse Water from Steel Pipe Mill

Acidic spent pickling solutions and rinse water are produced during steel pipe acid pickling. They are usually neutralised with lime in a neutralisation plant and pumped in the form of a wet sludge to a landfill. This is one of the main environmental issues of Russian steel mills. The implementation of sludge treatment units, including equipment for sludge polymer conditioning and dewatering, is an import consideration when seeking to reduce the impact of steel mills on human health and the environment. The researches results of polymer conditioning of the aggressive wastewater sludges by flocculants are reflected in the paper. Sludge samples were obtained from the neutralisation plant of an Ural’s steel pipe mill. Sludges of two types were investigated: the sludge which is formed in clarifiers during spent pickling solutions neutralization with lime and the sludge which is formed in clarifiers during rinse water neutralization with lime. During the work non-ionic, cationic, and anion flocculants Praestol® efficiency was estimated. The shortest time of water capillary suction from the flocculated sludge was accepted as efficiency criterion of flocculant processing. It was defined with use of the capillary suction timer Fann® and Whatman® 17 chromatographic paper. It is established that: non-ionic focculant Praestol® 2500 dose of 4–5 g/kg dry solids is effective for conditioning of the sludge produced during lime neutralization of acid spent pickling solutions; the anionic flocculant Praestol® 2540 dose of 1.5–2 g/kg dry solids is effective for conditioning of the sludge produced during lime neutralization of acid rinse water. The empirical response surfaces and the contour plots showing the relationship between capillary suction time and a dosage of flocculant and a charge density (% hydrolysis) of a flocculant were reveived. Keywords: steel pipe mill, acid pickling, wastewater, sludges, flocculants, capillary suction time

Development of a paper-based microfluidic device for the quantification of ammonia in industrial wastewater

Ammonia is a toxic pollutant increasingly found in urban and industrial wastewater and unprotected surface water. Industry discharges and fertilizer run-off release ammonia into sewers and streams, overloading wastewater treatment plants and causing fish deaths in surface water such as rivers, sea and lakes. The purpose of this study was to develop and evaluate the effectiveness of the microfluidic paper-based device (µPAD) for the quantification of ammonia in wastewater. The µPAD fabricated had an oval-shaped pattern which was designed using CorelDraw software. The hydrophilic zones were created by printing a chromatographic paper with a Xerox wax printer (Xerox colorqube 8570). The modified version of the colorimetric method using Nessler reagent was combined with microfluidic technologies to create a low-cost monitoring system for detection of ammonia in wastewater. The method allows for ammonia determination in the range of 0–5 ppm (mg/L) with a limit of detection of 3.34 ppm. This study indicated that a µPAD was successfully used to quantify the concentration of ammonia in wastewater.

Research of biologically active compounds of catalpa (Catalpa bignonioides Walt.)

Catalpa bignonioides Walt. (catalpa) the family Bignoniaceae – a tree, which originates from North America. Catalpa bark contains resins and tannins. Monoterpene glycosides were found in the leaf. Catalpa seeds contain up to 30% of eleostearic acid. Decoctions are made of the bark of the tree. They serve as a gastric agent and have an anthelmintic effect. Decoction of the bark exhibits bronchodilator action, is used in the complex treatment of cancer. The leaves are used to treat skin diseases. The infusion of fruits has anti-herpetic and hypoglycemic properties. The aim of the work is to investigate biologically active compounds of the leaves of catalpa bignini. The object of the study was the leaves of common catalpa harvested in the summer of 2018 in Sevastopol. Chemical identification reactions and methods of chromatographic analysis were used to determine the major groups of biologically active substances of the leaves of the catalpa (chromatographic paper Filtrak FN No. 4, Munktell, Czech Republic). Chromatography was performed in pre-selected solvent systems: n-butanol‒acetic acid‒water (BAW) (4:1:2) ‒ I direction and 15% acetic acid ‒ II direction. Identification reactions were performed with aqueous and aqueous-alcoholic extracts of catalpa leaves. The qualitative composition of the phenolic compounds was investigated by paper chromatography. The content of the sum of phenolic compounds, hydroxycyclic acids and flavonoids was determined by the spectrophotometric method. Based on the held reactions and chromatographic analysis, by the characteristic fluorescence in the filtered UV light before and after treatment with chromogenic reagents and the values of Rf in the raw material the presence of the following groups of biologically active substances were determined: flavonoids, phenol glycosides, hydroxycoric acids. According to the chromatographic analysis, at least 9 substances of phenolic nature have been detected in the alcohol-aqueous extracts. For the first time, the presence of the following groups of biologically active substances: hydroxycoric acids, phenologic glycosides, flavonoids was determined in the leaves of catalpa. Quantitative content of natural compounds in the leaves of common catalpa: the sum of phenolic compounds (4,76 ± 0,04%), of hydroxycoric acids (3,42 ± 0,02%), of flavonoids (1,88 ± 0,02%). The results of the study will be used in the development of the draft quality control methods for medicinal plant raw materials.

Printed Smart Devices on Cellulose-Based Materials by means of Aerosol-Jet Printing and Photonic Curing

Printed electronics is an expanding research field that can reach the goal of reducing the environmental impact on electronics exploiting renewable and biodegradable materials, like paper. In our work, we designed and tested a new method for fabricating hybrid smart devices on cellulose substrates by aerosol jet printing (AJP) and photonic curing, also known as flash lamp annealing (FLA), capable to cure low temperature materials without any damage. Three different cellulose-based materials (chromatographic paper, photopaper, cardboard) were tested. Multilayer capability and SMDs (surface mount devices) interconnections are possible permitting high flexibility in the fabrication process. Electrical and geometrical tests were performed to analyze the behavior of printed samples. Resulted resistivities are 26.3 × 10−8 Ω⋅m on chromatographic paper, 22.3 × 10−8 Ω⋅m on photopaper and 13.1 × 10−8 Ω⋅m on cardboard. Profilometer and optical microscope evaluations were performed to state deposition quality and penetration of the ink in cellulose materials (thicknesses equal to 24.9, 28.5, and 51 μm respectively for chromatographic paper, photopaper, and cardboard). Furthermore, bending (only chromatographic paper did not reach the break-up) and damp environment tests (no significant variations in resistance) where performed. A final prototype of a complete functioning multilayer smart devices on cellulose 3D-substrate is shown, characterized by multilayers, capacitive sensors, SMDs interconnections.