High-purity Solvents Research Articles

Использование смартфона в твердофазно-флуориметрическом определении некоторых полипептидных антибиотиков в лекарственных препаратах

The analysis of semi-products at different stages of production and finished medicinal products is an integral part of an effective quality assurance system for pharmaceutical production. The traditional methods used in the pharmaceutical field, such as capillary electrophoresis, gas and liquid chromatography, are quite versatile and effective. However, they are distinguished by the high cost of instrumentation and component materials, the need to use high-purity solvents, the lack of mobility and the possibility of in situ studies. Such shortcomings can be overcome by using the digital colorimetry method. Its significant popularization has been facilitated by the development of portable and personal electronic devices, among which the smartphone can be distinguished. The aim of the work was to develop a fast and simple method for the determination of a number of polypeptide antibiotics in drugs by digital colorimetry using a smartphone as a color recording device. To implement the solid phase fluorimetric determination of polypeptide antibiotics, HPTLC plates based on silica gel with an aluminum substrate were used as a matrix. Under these conditions, the fluorescence of actinomycin D, virginiamycin M1, virginiamycin S1, and novobiocin was observed when exposed to monochromatic radiation in the UV part of the spectrum (365 nm). The measurement of fluorescence intensity on the surface of the matrices was carried out using a smartphone. Calibration characteristics were constructed for the determination of polypeptide antibiotics in the concentration range of 32–500 μg/mL. The method for assessing the quality of finished drugs was tested on commercial products “Piostacin”, “Cosmegen”, “Dactinomycin” purchased in retail chains. The relative standard deviation of the analysis results does not exceed 0.05. The duration of the analysis was 10–15 min. Based on the results of the studies, the paper presents a method for determining some antibiotics of the polypeptide series by the intrinsic fluorescence of deposited solutions on a solid substrate during treatment with monochromatic UV radiation. The experimental delivery conditions used allow the analysis of drugs based on actinomycin D, virginiamycin M1, virginiamycin S1, and novobiocin.

Contamination Control During Sample Preparation for Trace Element Analysis of Electronic Cigarette Aerosol with Inductively Coupled Plasma-Mass Spectrometry, Part 2

Part 1 of this tutorial addressed how environmental contamination may be minimized by using proper personal analytical practices, sample preparation environmental suggestions, avoidance of glass and low purity quartz contact with samples and standards during sample collection and preparation, and appropriate choices of high purity solvents during sample collection and preparation. Part 2 continues the discussion in terms of minimizing sample contamination issues by using high purity polymer materials for sample collection and preparation, as well as discuss the differences between instrument and method limits of detection (LODs). Accepted and appropriate procedures for calculating method LODs are related to variability in instrument response and unavoidable environmental contamination during even the cleanest sample preparation. Adherence to such practices will help analysts avoid false positives and report results with a high level of confidence.

Reaction Conditions‐Dependent Formation of Catalytically Active Palladium Complexes or Palladium Nanoparticles on a Silica Support

AbstractSilica nanoparticles carrying covalently bound dipyridylmethylene (dpm) ligands were treated with Pd(OAc)2 in acetone in an attempt to prepare a silica surface‐immobilized Pd2+‐dpm complex. However, instead of the expected tethered complexes, small, monodisperse and evenly distributed palladium nanoparticles (PdNPs) formed. We found that an organic impurity, most likely an alcohol, in reagent‐grade acetone led to the reduction of Pd(OAc)2 to form PdNPs. The size and surface distribution of the PdNPs are affected by temperature, and formation of PdNPs can be inhibited by using high purity solvents and/or low temperature. The PdNPs supported on silica nanoparticles demonstrated catalytic activity in oxidation of benzyl alcohol to benzaldehyde, while silica nanoparticles with surface‐immobilized Pd2+‐dpm complexes required an induction period in order to reach a similar level of catalytic activity. In all cases, PdNPs were observed after the catalytic reaction, providing evidence that the induction period exhibited by the materials carrying Pd2+‐dpm complexes may be related to a time‐dependent PdNP formation process, with PdNPs rather than the immobilized complexes playing a central role in the catalytic reaction. Although nanoparticles are sometimes identified after carrying out catalytic reactions with supported molecular Pd complexes, our studies demonstrate the importance of identifying the species present in as‐synthesized heterogeneous materials of supported transition metal complexes.

Standing Wave Design of 2-Zone Thermal Simulated Moving Bed Concentrator (TSMBC)

A two-zone thermal SMB concentrator (TSMBC) can concentrate solutes and recover high purity solvents for dilute feeds. Literature design methods only provide a region of acceptable design parameters, thus requiring many trial-and-error simulations to determine the optimum design. In this study, a Standing Wave Design (SWD) method is developed for a two-zone TSMBC for linear and nonlinear isotherms, and verified with Aspen Chromatography simulations. SWD allows for direct solution of the optimal operating parameters for a TSMBC. A TSMBC is more effective for concentrating dilute solutions. As feed concentration increases, the enrichment factor decreases due to limited adsorbent capacity. A higher enrichment factor is obtained at the cost of a lower feed throughput and higher energy consumption. A TSMBC is more energy efficient than a single stage evaporator or temperature swing adsorption. It also has higher feed throughput and higher enrichment factor than Temperature Swing Adsorption (TSA) for dilute feeds.

Feasibility study of solvent recycle process in spin-on hard mask material manufacturing system

The spin-on hard mask material for photo resist in semiconductor industry is usually obtained from a small-scale batch process. To obtain high purity products requires multiple-step purification processes, during which a large amount of organic solvent waste is emitted. In this study, a process for regenerating high purity solvent was pro- posed and the economic efficiency of the proposed process was analyzed. Also, a sensitivity analysis was performed to analyze the changing economics regarding the main variables. From the analysis, the break-even point can be achieved within one year for different cases considered. On the basis of 4-year operation, the profit margins for each case were determined and compared. It is concluded that the waste solvent regeneration process for spin-on hard mask material production in semiconductor industry is feasible and recommended.

An integrated in situ extraction-gas stripping process for Acetone–Butanol–Ethanol (ABE) fermentation

A novel integrated in situ extraction-gas stripping process (Process 3 in this study) is proposed for running batch Acetone–Butanol–Ethanol (ABE) fermentation. The process involves two butanol separation processes in which butanol is first extracted by oleyl alcohol during ABE fermentation and gas stripping is carried out on butanol in the oleyl alcohol phase at the same time. The butanol productivity and yield of Process 3 is 0.28±0.01g/L/h and 0.226±0.001g-butanol/g-glucose. The ABE productivity and yield are 0.46±0.01g/L/h and 0.374±0.002g-ABE/g-glucose. Glucose utilization was 97% and initial glucose consumption was 121±2g/L. Butanol and ABE concentrations of 93–113 and 166–204g/L in the condensate can be achieved. This study demonstrates that Process 3 as described here enhances ABE fermentation and also results in the production of high purity solvents.

Known purity—the fundament of element determination by atomic spectrometry

Millions of measurements are performed each year by liquid based analytical atomic spectrometry to support healthcare, diagnostic tests, environmental monitoring, material assay, product development and safety. Despite the effort to develop absolute methods, most methods still depend on calibration solutions, which are gravimetric mixtures of high purity solvents and high purity (source material) metals or compounds. As in the real world ideal purity does not exist, the impurity of the solvent and the purity of the source material needs to be known. The impurity of a solvent with respect to one analyte can be measured rather easily and with low limits of determination. In contrast the measurement of the purity of the source material, i.e., the mass fraction of the main constituent in a high purity metal, is more difficult to determine. It becomes even more difficult when the source material is not a pure metal but a compound since problems regarding stoichiometry arise additionally. Although the major producers of calibration solutions make a special effort to determine the purity of the source material, the actual purity statement is often incomplete or not demonstrated. The main reason for this situation is the complexity and high effort necessary to fully characterize such a material. This problem holds to a very wide extent also for the primary standards for element determination at the National Metrology Institutes and Designated Institutes (NMIs and DIs). It is the task of the NMIs and DIs to realise and disseminate primary standards for providing traceability to the International System of Units (SI). The primary elemental standards at the NMIs should provide the link to secondary standards produced by commercial producers and other independently prepared standards for element determination. Without such primary standards, elemental calibration solutions may vary and, depending on the uncertainty required, comparability of measurement in time and space results cannot be achieved.

Organic solvent nanofiltration: a potential alternative to distillation for solvent recovery from crystallisation mother liquors

Increasing demand for more sustainable processing has led to a renewed interest in the area of solvent recovery within the pharmaceutical industry. Distillation has been the conventional unit operation of choice, and though generating high purity solvent, distillation can be energy-intensive and a low energy alternative is desirable. A potential method has been identified in emerging separation technique organic solvent nanofiltration (OSN). The work presented here investigates the feasibility of using OSN as an alternative to distillation for solvent recovery. Results demonstrate that OSN is capable of recovering organic solvent with a purity suitable for re-use in subsequent active pharmaceutical ingredient (API) crystallisation. Energy-efficiency calculations for this case study demonstrate that OSN uses 25 times less energy per L of recovered solvent when compared to distillation. However, the efficiency of membrane based solvent recovery is restricted by solubility of the compounds within the waste stream which resulted in recovery of less solvent for OSN. Equivalent recovery volumes can be obtained by using a combined approach of OSN and distillation with the energy consumption remaining 9 times lower than when distillation is used alone.

Streamlined Combustion Gas Measurements for Improved National Dioxin Inventories

The analysis of PCDD/Fs requires advanced analytical instruments and is a complex, labor intensive process that consumes large quantities of high-purity solvents. It is therefore very expensive and thus problematic--or even impossible--for developing countries to afford to establish reliable PCDD/F source inventories in support of global and national emission reduction strategies. Low-cost reliable alternatives are needed to improve this situation. Therefore, a streamlined procedure for flue gas sampling and analysis has been developed and evaluated that utilizes a user-friendly polyurethane foam plug (PUFP) sampling technique. The collected samples are then shipped to a central laboratory for analysis where they are processed using a cost-efficient pressurized liquid extraction procedure with in-cell carbon cleanup (PLE-C) prior to analysis by gas chromatography--high-resolution mass spectrometry (GC-HRMS). The PLE-C technique has previously been validated for a range of matrices, and, in the present study, has been further improved by introducing an extraction cell coupling cartridge. The entire procedure was evaluated using three sets of samples: two from a laboratory-scale incinerator and one from a full-scale incinerator. The samples were expected to differ in PCDD/F levels and homologue patterns. Each sample was split and analyzed in parallel by both PLE-C and a reference procedure (Soxhlet extraction followed by a traditional multistep cleanup procedure, Sox-T). The results of analysis by PLE-C compared well with those from analysis by Sox-T. The difference between toxic equivalent (TEQ) values obtained using the PLE-C and reference technique for 11 PUFP samples ranged from -10% to +44% and the two techniques also yielded very similar PCDD/F homologue profiles. A principal component analysis (PCA) of the data showed that both methods were able to discriminate among the three sets of samples, thereby demonstrating that the between method variability was less than the between-sample variability. In summary, the results indicate that PUFP sampling followed by PLE-C extraction and cleanup provides a fast, relatively cheap, and reliable method for analysis of PCDD/Fs in flue gas.

Ultrathin SiO2 on Si. I. Quantifying and removing carbonaceous contamination

An analysis is made of the amount of carbonaceous contamination remaining on silicon wafers with a thin oxide overlayer. Wafers are either left “as-received” or deliberately contaminated with a thumbprint and then subjected to one of 42 different cleaning procedures with the remaining carbon level monitored by x-ray photoelectron spectroscopy (XPS). The XPS measurement of the carbon level in terms of a thickness in nm, using the traditional equation, depends sensitively on the assumed form of the carbon; the thickness for an average polymerlike contamination being computed as 1.67 times the thickness for a glassy carbon layer for a given spectrum. However, if the measurement is defined in terms of carbon atoms/m2, this sensitivity is removed. Alternatively, if absolute measurements are used, the sensitivity in terms of the thickness in nm is also reduced and the data are consistent with the results for the average polymer. Of the cleaning methods, ultraviolet radiation with ozone is best but this affects the substrate by increasing the oxide thickness by approximately 0.2 nm and so is not recommended for work where the oxide thickness should remain unaltered. The best group of methods that leave the oxide unaltered are those involving an overnight soak in a high purity solvent such as isopropyl alcohol (IPA), chloroform, or heptane, followed by an ultrasonic agitation for 1 min in fresh solvent, a rinse in further fresh solvent, and drying in an argon jet. This reduces the final carbon level to thicknesses, in terms of an average polymer, of around 0.16 nm, with IPA giving the best result for the selected solvents. This level may be further reduced, by heating on a hot plate in air to 325 °C for 15 min, to a final thickness of 0.12 nm. Cleaned samples that are then stored in glass or Fluoroware polypropylene containers retain much of their cleanness and the carbonaceous contamination does not exceed 0.26 nm during the 100 days of the study.

Electrochemical cell system for voltammetry of high purity solvents

A two-compartment cell system was designed to carry out high purity electrochemical experiments. Features of this cell include a monolithic quartz body, quartz isolation frit, pretreated platinum electrode, hydrogen reference electrode, snap-on cell tops, purified “type I” water, high purity supply gases, fluoropolymer tubing, and gas-tight cell integrity. An advantage of this design is the allowance for internal pre-electrolysis of the test solution. The system was quality tested by obtaining cyclic voltammograms of 0.5 molar sulfuric acid solution. To demonstrate its utility for high purity work, novel cyclic voltammograms of type I water were obtained with a platinum microelectrode in the absence of electrolyte. The water voltammograms exhibited three electroactive features: reduction potential limit near E=−0.2 V versus r.h.e. (H2), oxidation potential limit near E=+1.6 V (O2), and one surface reduction peak at E=+0.4 V. Thus, the voltammetric “potential window” for water was determined to be 1.8 V.

Automated solid-phase extraction and coupled-column reversed-phase liquid chromatography for the trace-level determination of low-molecular-mass carbonyl compounds in air

This study reports the development of a coupled-column RPLC method for the trace level determination of several volatile aldehydes in ambient air. Carbonyls in air are sampled using a ozone scrubber and SPE C 18 cartridges which are pretreated with 2,4-dinitrophenylhydrazone. The method is used for the separation of 13 different aldehydes and ketones. All analytes are separated without high blanks or ozone interferences. The analytical detection limits for most important compounds formaldehyde, acetaldehyder, 2-propenal (acroleine), 2-butenal (crotonaldehyde( and benzaldehyde, range from 50 to 150 ng/m 3 (ppt) or 0.5–1.0 pmol/l, with relative standard deviations of 6%. The sampled air volume was 200 1. Due to the high sensitivity of the method, high purity solvents must be used. The analytical method as described below, has high recoveries for all analytes ( >90%) and is fully automated. this procedure has been applied in a pilot study with 60 air samples.

Mallinckrodt buys lab supplier J. T. Baker

Combining two of the most eminent names in laboratory reagent chemicals, Mallinckrodt Group has agreed to buv J. T. Baker from Procter & Gamble. Mallinckrodt will announce the purchase price when the deal closes. Baker, based in Phillipsburg, N.J., makes lab, industrial, and electronics chemicals—with sales in 1993 of about $I30 million. The 4,500 or so items in its lab products catalog include organic and inorganic chemicals, high-purity solvents, chromatography supplies, biological reagents, and safety equipment. The firm also sells about 1,000 chemicals in large volumes to the drug, biotechnology, electronics, ceramics, and rubber industries. Its electronics chemicals are high-purity, low-particulate acids, solvents, etchants, and photoresist developer agents used to fabricate semiconductor devices. Baker was founded by John Townsend Baker in 1904. In 1941, it was purchased by Vick Chemical Co., which later became a division of Richardson-Merrell. Procter & Gamble acquired Baker in 1985 as a result of ...

Absence of hepatitis A virus transmission by high‐purity solvent detergent treated coagulation factor concentrates in Scottish haemophiliacs

Recent reports of hepatitis A virus (HAV) infection in haemophiliacs receiving high-purity solvent detergent (HP.SD) treated factor VIII concentrates have brought into question the efficacy of this virucidal method for inactivating HAV. To assess whether HAV may have been transmitted by HP.SD concentrates, we compared seroprevalence in haemophiliacs with different disease severity, sought evidence of seroconversion to HAV since introduction of HP.SD products, and directly examined concentrates for HAV RNA by PCR. Our data suggest that Scottish haemophiliacs are not being infected with HAV by HP.SD concentrates produced initially by CRTS Lille and presently by PFC Edinburgh and supplied by the Scottish National Blood Transfusion Service (SNBTS).

Use of an ultrasonic nebulizer with membrane desolvation for analysis of volatile solvents by inductively coupled plasma atomic emission spectrometry

The petroleum and chemical industries need a rapid, and sensitive technique for the trace analysis of volatile feedstocks, intermediates and products, including high-purity solvents. Organic solvent loading of the inductively coupled plasma (ICP) adversely effects the application of ICP atomic emission spectrometry to analysis of volatile organic liquids when conventional sample introduction equipment is employed. The use was investigated of a membrane separator as a secondary desolvation device used with an ultrasonic nebulizer (USN) to further reduce organic vapour loading of the plasma and enable µg l–1 determinations to be performed on solvents and petroleum products boiling well below 100 °C. Two prototype membrane desolvator units and the final commercial unit were tested on a variety of materials including hexanes, methanol, tetrahydrofuran, acetone and dichloromethane. Organic vapour removal was efficient enough to permit the analysis of these materials at ‘normal’ sample introduction rates (1–4 ml min–1) and practical operating conditions. Detection limits similar to aqueous solution USN limits were achieved. Owing to the near complete solvent matrix removal provided by the USN-membrane sample introduction system, ‘universal calibration’ of the ICP should be possible at certain ICP operating conditions. Experiments were conducted with the goal of achieving a single calibration valid for a variety of volatile organic solvents. Accurate calibration was maintained for several diverse solvent types after applying corrections for solvent nebulization efficiencies relative to the calibration solvent.

Strategies for Rapid GC Impurity Analysis of High-Purity Solvents I: Instrumentation and Procedures

Timing considerations are discussed for an instrumentation system designed for the rapid determination of impurities at part-per-million (ppm) levels in high-purity solvents. Isothermal retention times in the range from a few seconds to about 20 s are obtained using 2–4-m lengths of 0.25-mm i.d. fused-silica capillary columns. The use of a cryofocusing inlet with flow direction control for performing solvent flush and backflush operations is described. A model is presented for the operation of the cryofocusing inlet system. The system can be used to collect a vapor sample at either end of the cryofocusing trap and reinject it as a relatively narrow plug. The effects of inlet system injection temperature on retention time are considered for samples injected from both the upstream and downstream ends of the trap.

Determination of impurities in high-purity solvents by neutron activation analysis

The determination of impurities in high-purity solvents, (acetone, isopropanol, trichloroethylene and trichlorotrifluoroethane) used in the production of integrated circuits was carried out by reactor neutron activation analysis. A special vacuum evaporation technique was used for the preconcentration of the solvents. The results showed that sodium and iron are the main impurity components in the solvents and on the other hand the quality of the solvents satisfies the specifications required by high-technology standards. The suspended solid particles in solvents were counted by a Microscopic Image Analysis System (MIAS).

High purity fluoropolymer materials: Trace element content and leaching

Many problems in analytical chemistry are shared by the high purity crystal growth community since both are greatly concerned with the effects of impurities either upon an analysis or upon a device. Fluoropolymers are widely used today in applications where inertness or high purity or both are needed. The behavior of these polymers in high purity solvent systems has been investigated by several analytical techniques. Both the resin from which finished parts are made as well as blow molded bottles have been evaluated to determine cationic impurities in both the resin and in leachates.

Gas chromatographic determination of organic impurities in solvents for liquid chromatography

Methods for the gas chromatographic determination of organic impurities (with a detection limit of 5 · 10 −4−5 · 10 −5%) in solvents for liquid chromatography have been developed to supply technologists with a reliable means of analytical control control in the commercial production of high-purity solvents. The series of solvents investigated included acetonitrile, methanol, ethanol, methylene chloride, formic acid, dimethylformamide, pyridine, tetrahydrofuran and dimethyl sulphoxide. Data on the content of major impurities in these above solvents and conditions for quantitative analysis are presented.

Calibration of MIRAN Gas Analyzers: Extent of Vapor Loss Within a Closed Loop Calibration System

The use of a Closed Loop Calibration System (CLCS) for calibration of several portable models of MIRAN infrared gas analyzers has been recommended by the manufacturer. The purpose of this study was to determine the extent of organic vapor loss due to wall adsorption that may result in erroneous light absorbance data. Two MIRAN-1A gas analyzers that had passed the performance and wavelength accuracy tests were connected in series to a bellows pump to form a CLCS. Fourteen organic solvents, with vapor pressure: 0.43-350 mm Hg (at 25°C), were used in the study. Increments (0.5-5 µL) of high purity solvents were introduced into the CLCS via a septum. Simultaneous gas chromatographic (G.C.) analyses were performed on aliquots of gas mixture drawn between consecutive injections of solvent liquid to determine the actual concentrations of organic vapors within the CLCS. Absorbance data were recorded separately for each gas analyzer. Two regression lines were established for each organic vapor: (i) between expecte...