Sampling Valve Research Articles

A Comprehensive Online Analytical System Coupled with Standardized Data Analysis for the Electrochemical Reduction of CO2

The electrochemical reduction of CO2 (CO2RR) is a promising way to convert detrimental CO2 emissions into sustainable fuels and chemicals, and thus to achieve a circular carbon economy. 1 Depending on catalyst type and reaction conditions, different gaseous and liquid products can be obtained from the CO2RR, and their production rates vary with reaction time. It becomes thus imperative, for any catalytic performance analysis, to be able to assess the product distribution online during CO2RR. 2,3 However, while gaseous products are readily analyzed online by gas chromatography, liquid products are typically only assessed at the end of the reaction due to the lack of suitable automated liquid sampling and analysis methods. In addition, reaction parameters such as CO2 mass flow rates, temperatures and pressures are seldom recorded, causing the loss of significant information on catalysts, electrodes, and electrolyzers behavior.To overcome these issues, we assemble a comprehensive analytical system coupling online gas and liquid product analysis by gas and liquid chromatography leveraging a special automated liquid sampling valve with electrochemical protocols that assess CO2RR performance, electrolyzer cell resistance and electrode surface area. In addition, we record CO2 mass flow rates, electrolyzer temperatures, as well as gas and liquid flow pressures. 4 To rapidly and reproducibly handle the large and heterogeneous data volume obtained we implement a standardized data pipeline based on our own open-source software,5 which automatically parses the numerous different raw data files, composes a data set following FAIR practices,6 and post-processes and plots the data in a standardized way. We validate the analytical system by carrying out CO2RR at 200 mA/cm2 on Cu gas diffusion electrodes, following the changes in selectivity with reaction time for > 10 gaseous and liquid products, and recording mass flow rates, electrolyzer temperatures and pressures. The modular nature of our analytical system, combined with the standardized data pipeline, allows us to freely increase the number and type of sensors used with minimal impact on the data analysis time, as well as to multiplex our analysis to 8 parallel electrolyzer cells, paving the way for a much deeper and faster understanding of the function of CO2RR catalysts, electrodes, and electrolyzers.

Advanced Analytical System with Standardized Data Analysis for Electrochemical CO2 Reduction

Electrochemical CO2 reduction (CO2RR) is a promising way to convert CO2 emissions into sustainable fuels and chemicals, approaching a circular carbon economy. 1 Depending on catalyst type and reaction conditions, different gaseous and liquid products can be obtained from the CO2RR, and their production rates vary with reaction time. Thus, assessing the product distribution online during CO2RR is a key component of any catalytic performance analysis. 2,3 However, while gaseous products are readily analyzed online, liquid products are assessed typically only at the end of the reaction due to the lack of suitable automated liquid sampling and analysis methods. In addition, electrolyzer parameters such as gas flow rates, temperatures and pressures are seldom recorded, causing the loss of significant information on catalysts, electrodes, and electrolyzers behavior.To overcome these issues, we assemble a comprehensive analytical system coupling online gas and liquid product analysis by chromatography (leveraging a special automated liquid sampling valve) with electrochemical protocols to assess CO2RR performance, electrolyzer cell resistance and electrode surface area. In addition, we record CO2 gas flow rates, electrolyzer temperatures, and gas and liquid pressures. 4 To rapidly and reproducibly handle the large and heterogeneous data volume obtained we implement a standardized data pipeline based on our own open-source software,5 which automatically parses the numerous different raw data files, composes a data set following FAIR practices,6 and post-processes and plots the data in a standardized way (see example in Fig. 1 below). We validate the analytical system by carrying out CO2RR at 200 mA/cm2 on Cu gas diffusion electrodes, following the changes in selectivity with reaction time for > 10 gaseous and liquid products, and recording mass flow rates, electrolyzer temperatures and pressures. The modular nature of our analytical system, combined with the standardized data pipeline, allows us to freely increase the number and type of sensors used with minimal impact on the data analysis time, as well as to multiplex our analysis to parallel electrolyzer cells, paving the way for a much deeper and faster understanding of the function of CO2RR catalysts, electrodes, and electrolyzers.

Automated Sampling System for Monitoring 85Kr in Air

Radioactive krypton-85 (85Kr) gas, a chemically inert and non-proliferation indicator, is derived from fission products. Its detection relies on the Budesamt für Strahlenschutz–Institute of Atmospheric Radioactivity (BfS-IAR) method, which necessitated impurity removal using soda lime, silica gel, and liquid nitrogen for cryogenic adsorption. This manual process requires frequent replacements, posing challenges for its automation. To address this, we developed a prototype krypton sampling system as an interim research product for the fully automated remote monitoring of covert nuclear activity. The system incorporates a hollow fiber membrane for impurity removal, a computer-controlled multi-position valve for sampling, and an electric cooler for adsorption. The impurity removal modules demonstrated high efficiencies, removing H2O and CO2 at 99.8% and 97.8% rates, respectively. Further, the custom-made sampling system can process 16 samples in a single run without analyst intervention. We conducted experiments to verify the automatic krypton sampling capability. The activity concentration of 85Kr in ambient air was measured using the BfS-IAR processing and detection system. The system exhibited a recovery rate of ~7.8% for krypton in 1000 L air, demonstrating good continuous remote monitoring capability. This study promotes the development of an automated analysis system for the detection of 85Kr in ambient air.

Evaluation of the near-wall gas composition in SI-engines using fast gas sampling

Future internal combustion engines using novel fuels and combustion systems have the potential to achieve ultra-high efficiency and lowest pollutant emissions to comply with future regulatory requirements. Realizing indicated efficiencies over 50% with ultra-lean low temperature combustion face new challenges. To meet this goal, hydrocarbon (HC) and carbon monoxide (CO) emissions need to be reduced significantly further. To do this, knowledge must be gained about how the operation regime of the engine affects the HC and CO emissions. Since these emissions partly originate from areas where flame quenching occurs, an investigation of the gases near the wall is of interest. To this end a fast gas sampling method is being developed to extract and analyze the gas from the combustion chamber. The used fast gas sampling valve from Kistler enables sampling durations of less than 1 ms. Fourier-transform-infrared spectroscopy and a fast mass spectroscopy allow the determination of the sample composition. The valve is positioned inside the cylinder head of a single cylinder engine between intake and exhaust valves. In order to assess the effects of engine operating conditions on the formation of HC and CO at the cylinder walls, the measurement uncertainty of the setup must be evaluated. Since the combustion process is subject to cyclic variations, the evaluation of only a few individual measurements is not meaningful. Therefore, mean values are determined from the evaluation of several measurements not performed consecutively. By examining the mean and standard deviation of these measurements for each species, one can determine a measurement error. In comparison, lean operation with RON95E10 fuel at an IMEP = 12 bar and an engine speed of n = 2000 1/min shows a significant reduction in intermediate hydrocarbon species such as acetylene and a significant increase in fuel species such as ethanol compared to stoichiometric operation.

Kinerja Inert Gas Generator Untuk Mendapatkan Oksigen Konten 3% Pada Gas Lembam

Inert Gas System is a machine that functions as a security system to prevent explosions on tankers. Explosion prevention is carried out by introducing inert gas into the cargo tank with the aim of reducing oxygen levels in the cargo tank atmosphere so as to prevent the formation of a flammable gas mixture. Inert gas contains very little oxygen, namely 1-2% by volume. The device that produces the inert gas is called the Inert Gas Generator (IGG). The purpose of this study was to determine the factors that cause high oxygen content contained in the inert gas and the efforts made related to the factors mentioned so that the inert gas generator can work optimally. The research method used by the author is descriptive qualitative with Fishbone data analysis techniques and SWOT analysis. The results of the study stated that the factors causing oxygen content of more than 3% were dirty fuel filter, too much combustion air supply, oxygen analyzer that was rarely calibrated, flow sampling was too large, fuel quality was not good, lack of crew knowledge. to PMS (Plan Maintenance System) IGG. Efforts have been made to clean the fuel pump filter, close the air capacity valve a little, calibrate the oxygen analyzer according to the PMS schedule, reduce the sampling valve flow into the oxygen analyzer, add fuel oil treatment (additives) to the fuel, pay attention to the IGG maintenance schedule according to PMS, restore the maintenance implementation system based on the PMS inert gas generator schedule.

Measurements and Modelling of Vapour–Liquid Equilibrium for (H2O + N2) and (CO2 + H2O + N2) Systems at Temperatures between 323 and 473 K and Pressures up to 20 MPa

Understanding the phase behaviour of (CO2 + water + permanent gas) systems is critical for implementing carbon capture and storage (CCS) processes, a key technology in reducing CO2 emissions. In this paper, phase behaviour data for (H2O + N2) and (CO2 + H2O + N2) systems are reported at temperatures from 323 to 473 K and pressures up to 20 MPa. In the ternary system, the mole ratio between CO2 and N2 was 1. Experiments were conducted in a newly designed analytical apparatus that includes two syringe pumps for fluid injection, a high-pressure equilibrium vessel, heater aluminium jacket, Rolsi sampling valves and an online gas chromatograph (GC) for composition determination. A high-sensitivity pulsed discharge detector installed in the GC was used to measure the low levels of dissolved nitrogen in the aqueous phase and low water levels in the vapour phase. The experimental data were compared with the calculation based on the γ-φ and SAFT-γ Mie approaches. In the SAFT-γ Mie model, the like parameters for N2 had to be determined. We also obtained the unlike dispersion energy for the (H2O + N2) system and the unlike repulsive exponent and dispersion energy for the (CO2 + N2) system. This was done to improve the prediction of SAFT-γ Mie model. For the (H2O + N2) binary system, the results show that the solubility of nitrogen in the aqueous phase was calculated better by the γ-φ approach rather than the SAFT-γ Mie model, whereas SAFT-γ Mie performed better for the prediction of the vapour phase. For the (CO2 + H2O + N2) ternary systems, both models predicted the experimental data for each phase with good agreement.

Hydrogen-Rich Gas Produced by the Chemical Neutralization of Reactive By-Products from the Screening Processes of the Secondary Aluminum Industry

In the framework of the industry of secondary aluminum, the chemical neutralization of highly reactive materials that come from the pre-treatment screening processes of scraps (beverage cans and domestic appliances) was investigated through experiments in aqueous alkaline solutions. Metallic aluminum-rich by-products are classified, according to EU law, as dangerous waste, as they can potentially develop flammable gases capable of forming explosive mixtures with air. In this way they cannot be disposed of in landfills for non-hazardous wastes if chemical neutralization is not planned and performed beforehand. In this way, these experiments were mainly aimed at unraveling the oxidation rate and at quantifying the production of hydrogen-rich gases from the reactions of the metallic aluminum-rich by-products in a water-rich alkaline (liquid or vapor) environment. Reactions were carried out in a stainless-steel batch mini-reactor with metering and sampling valves, with the resulting gases analyzed by gas-chromatography (GC). The experimental setup was planned to avoid the following issues: (i) the corrosion of the reactor by the alkaline solution and (ii) the permeability of the system to hydrogen (i.e., possible leaks of H2), related to the fast kinetics and short duration of the reactions (which may hinder a pile-up-effect) between the solid by-products and the liquid. The procedure was defined by a controlled interaction process between metals and liquid, using NaOH to increase reaction rates. The experimental runs performed in the mini-reactor proved to be effective for eliminating the reactive metallic aluminum, reaching a maximum hydrogen production of 96% of the total gases produced in the experiments. The relations between gas generation (up to 55 bar of H2 in the experiments, which lasted for four days) and each specific parameter variation are discussed. All the obtained results can be transferred and applied to (i) the possible industrialization of the method for the chemical neutralization of these dangerous by-products, increasing sustainability and workplace safety, (ii) the use of the resulting hydrogen as a source of energy for the furnaces of the secondary aluminum industry itself, and (iii) new technological materials (e.g., “foamed geopolymers”), by using hydrogen as a foaming agent, coupled with aluminosilicate materials, during geopolymeric reactions.

On-line micro GC testing of protium analysis in DT fuels from TCAP products

To support Chinese Inertial Confined Fusion research, a thermal cycling absorption process (TCAP) system was previously developed for protium removal from D–T fuels. However, to monitor the product quality in each TCAP cycle (10 min), an on-line analysis method is required. At ITER, the Analytical System is an individual system used, which meets the static analysis requirement via interconnecting lines. In this study, to meet the dynamic analysis requirement, a new on-line micro gas chromatography system is installed in this system glovebox and is directly connected to the sampling point. For proximity to the sampling point, its sampling valve is connected with two 10-cm, 1/16-inch stainless steel tubings. Two six-port valves are combined to perform the sampling cycle of “vacuum-loading-injection.” A 30 m MnSO4 deactivated alumina metallic PLOT column is prepared for sufficient resolution of hydrogen isotopes at 77 K. The results show that the D2 retention time is 3.6 min, and that the resolutions between H2 and HD and between HD and D2 were 1.5 and 3.8, respectively. The estimated lower detection limit of HD was 20 ppm for a sampling volume of 1 cm3. The times of sample loading, sample injection, and vacuum were 1, 0.5, and 2.5 min, respectively. A D–T mixture testing is in progress.

Characterizing the Performance of a Compact BTEX GC-PID for Near-Real Time Analysis and Field Deployment.

In this study, we test the performance of a compact gas chromatograph with photoionization detector (GC-PID) and optimize the configuration to detect ambient (sub-ppb) levels of benzene, toluene, ethylbenzene, and xylene isomers (BTEX). The GC-PID system was designed to serve as a relatively inexpensive (~10 k USD) and field-deployable air toxic screening tool alternative to conventional benchtop GCs. The instrument uses ambient air as a carrier gas and consists of a Tenax-GR sorbent-based preconcentrator, a gas sample valve, two capillary columns, and a photoionization detector (PID) with a small footprint and low power requirement. The performance of the GC-PID has been evaluated in terms of system linearity and sensitivity in field conditions. The BTEX-GC system demonstrated the capacity to detect BTEX at levels as high as 500 ppb with a linear calibration range of 0–100 ppb. A detection limit lower than 1 ppb was found for all BTEX compounds with a sampling volume of 1 L. No significant drift in the instrument was observed. A time-varying calibration technique was established that requires minimal equipment for field operations and optimizes the sampling procedure for field measurements. With an analysis time of less than 15 min, the compact GC-PID is ideal for field deployment of background and polluted atmospheres for near-real time measurements of BTEX. The results highlight the application of the compact and easily deployable GC-PID for community monitoring and screening of air toxics.

Experimental study of impurity freeze-out in ternary methane + ethane + benzene mixtures with applications to LNG production

The freeze-out of impurities in LNG production can pose significant operational risks and lead to costly blockage-induced plant shutdowns. Study of ternary and higher-order mixtures, which are more analogous to LNG, present the critical tests of thermodynamic models in terms of their utility and predictive accuracy. In this work, a visual CryoSolids apparatus was upgraded to allow analytical measurements of solvent composition in multi-component systems where a solid phase is present at equilibrium. The analytical system, which included a ROLSI sampling valve and capillary together with a gas chromatograph, was successfully commissioned and used to measure melting temperatures and solvent compositions of a ternary mixture containing methane, ethane, and benzene at temperatures down to 125 K and pressures up to 6 MPa. The effect on the solubility of benzene by adding ethane to the solvent was investigated by varying the ethane mole fraction from 0 to 0.96. The resulting temperature at which benzene melted into the liquid solvent decreased from 246 K at 4.7 MPa to 125 K at 5.7 MPa. The comparison of results with the ThermoFAST model showed that it could describe the new data with a deviation less than 1 K for ethane liquid phase mole fractions from 0 <xC2< 0.5, which increased to less than 4 K for 0.85 <xC2< 0.97. This result indicates that ThermoFAST satisfactorily represents SFE conditions in LNG mixtures of industrial relevance but needs improvement to cover wider ranges of composition.

Microbial decontamination of particulate food using a pilot-scale atmospheric plasma jet treatment system

A pilot-scale treatment system of atmospheric plasma jet (APJ) was developed and its effects on the inactivation of natural bacteria in rice germ, black pepper powder, and sesame were investigated. The optimal sample amount, rotary valve speed, operation time, and plasma jet pressure for inactivation were determined to be 200 g, 40 rpm, 10 min, and 0.2 MPa, respectively, which inactivated natural bacteria in rice germ, black pepper powder, and sesame by 1.4, 1.0, and 1.4 log CFU/g, respectively. Dust removal pre-treatment increased the microbial reduction level in sesame by 2.2 log CFU/g. Plasma treatment did not alter the color of rice germ and sesame and the antioxidant activities of black pepper powder and sesame. The plasma jet treatment system consumed 1.6 times less energy than conventional heat treatment. The results demonstrated the potential of using the pilot-scale APJ system for microbial disinfection of particulate food. • Pilot-scale atmospheric plasma jet is effective in decontaminating particulate food. • Bacterial reduction varies with sample amount, valve speed, and operation time. • Dust removal before plasma treatment increases bacterial reduction levels on sesame. • Pilot-scale plasma jet disinfects particulate food without affecting food quality.

A Pressure-Tight Sampler with Flexible Titanium Bag for Deep-Sea Hydrothermal Fluid Samples

AbstractThis paper details the development and application of a novel pressure-tight sampler with a metal seal capable of acquiring high-purity fluid samples from deep-sea hydrothermal vents. The sampler has a titanium diaphragm valve for sampling and a flexible titanium foil bag to store the fluid sample. Hence, all parts of the sampler in contact with the sample are made of titanium without elastomer O-ring seals to minimize the organic carbon blank of the sampler, which makes it suitable for collecting organic samples. A pressure-tight structure was specially designed to maintain the sample at in situ pressure during the recovery of the sampler. The sampler has been successfully tested in a sea trial from November 2018 to March 2019, and pressure-tight hydrothermal fluid samples have been collected.

Plasma Oxidation of Cu for Electrochemical CO2 Reduction

Tuning the selectivity of copper-based catalysts towards the formation of C2 hydrocarbon products has become the main driving force in the development of CO2 reduction electrocatalysis. In particular, Oxide derived Cu (OD-Cu) has been proven to significantly increase the formation of C2 hydrocarbons, in which ethylene is produced at the expense of methane [1]. Further, the selectivity is tunable by controlling the oxide thickness and the ratio of Cu+ to Cu2+ [2]. Oxygen plasma have been especially successful in developing Cu-based catalysts since it gives a good control of the oxidation conditions. The large increase in surface roughness is also believed to stabilize Cu+ during the CO2 reduction reaction (CO2RR) [3]. The latter has shown to be a prerequisite for CO dimerization, due to the attractive forces resulting from the oppositely charged *CO on the Cu0 and Cu+ sites [4]. In this paper, we present a method for tuning the selectivity of Cu catalysts through a controlled oxidation process using oxygen plasma. The effect of plasma exposure time on the catalytic performance will be investigated.A plasma cleaner (Plasma Parylene Systems, Alpha Plasma AL18, Germany) was used to oxidize high purity copper foils (Jiarun Metal Material Corporation, China, 99.9999%) to prepare the catalysts. The plasma power was set to a constant 400 W in an O2 atmosphere at a pressure of 60 Pa, while varying the exposure time from 15 to 60 minutes. Prior to plasma oxidation, the Cu foils were cleaned in an ultrasonic bath of acetone for 25 minutes. Then, 10 minutes of Ar plasma (300 W at 38 Pa) were used prior to oxidation in order to remove any surface contaminants.Visually, the samples appear red, purple, and blue-grey for exposure times of 15, 30, and 60 minutes, respectively (figure 1). The sample exposed to oxygen plasma for 15 minutes has a granular morphology with clearly defined grains (~ 50 nm), which gradually grows together when doubling the exposure time to 30 minutes, and eventually leads to a continuous film when the exposure time reaches 60 minutes (figure 2). Electron Dispersion Spectroscopy (EDS) analysis shows a steady increase in oxygen concentration as a function of plasma time (figure 2). The visually observed color difference can be attributed to the difference in oxide concentration as well as the surface morphology of the samples, which can explain the untraditional colors of our copper oxides.The electrochemical measurements will be performed using an H-cell equipped with a Nafion 117 proton exchange membrane, where the cathodic and anodic compartments are each filled with 20 mL of 0.1M KHCO3, while CO2 is bubbled through the solution at a constant flow rate of 20 sccm. Catalytic performance is to be determined using an electrochemical workstation (CHI23213). Furthermore, quantification of the reaction products will be accomplished using a gas chromatograph (Shimadzu GC 2010 PLUS) equipped with a gas sampling valve (GSV) and a barrier discharge ionization (BID) detector. The experiments will be performed in an online configuration with a constant flow of CO2. In summary, this work will provide new insight into plasma-oxidized copper catalysts for electrochemical CO2 reduction.

INFLUENCE OF BACKGROUND ELECTROLYTE AND SURFACE-ACTIVE SUBSTANCES ON EFFICIENCY OF ELECTRO-FLOTATION EXTRACTION OF HARDLY SOLUBLE EUROPIUM COMPOUNDS

Europium and its compounds are widely used in high-tech processes of nuclear and hydrogen energy, electronics, medicine and other fields. In this work, the regularities of electroflotation extraction of hardly soluble europium compounds from model systems were obtained and analyzed. The aim of the work is to obtain data on the process of electroflotation extraction of hardly soluble europium (III) compounds from model systems with background electrolyte and the addition of surface-active substances, establishing optimal conditions for efficient extraction of hardly soluble europium (III) compounds. The research was conducted at room temperature (20 ± 2 °C) in a non- current electric flotator of periodic action, which is made in the form of a vertical column. The cross-sectional area of the electric flotator is 10 cm2, the volume of the treated solution is 500 ml, the height of the apparatus is 800 mm, and the sampling valve is located at a height of 40 mm from the electrode unit. The electrode unit consists of an insoluble anode made of ORTA (titanium with ruthenium oxide coating) and of a cathode made of stainless steel mesh (cell size 0.5 × 0.4 mm, wire thickness 0.3 mm). The mass concentration of europium (III) was determined by a mass-spectrometer with inductively coupled plasma of Termo Scientific brand. Determination of particle size and particle size distribution, surface charge of particles of the dispersed phase (ξ) were carried out using a Photocor Compact-Z laser particle analyzer. The efficiency of the process of extracting hardly soluble compounds of Eu3+ was evaluated by the degree of extraction α (%). The objects of study are colloid-dispersed systems of poorly soluble compounds of europium (III) in aqueous solutions in the presence of surface-active substances of various nature and background electrolytes. The initial aqueous solution contains: СEu3+ - 0.1 g/l, Cbackground electrolyte - 1 g/l, background salts: NaCl, NaNO3, Na2SO4; Csas - 5 mg/l. It has been shown that for each type of solution the efficiency of the electroflotation process is achieved at certain pH. It is established that the optimal conditions for the extraction of europium (III) compounds are: volume current density, Jv = 0.4 A/l; process duration 10 min. For nitrate background the degree of extraction is maximum at pH 10 - 11 and at the presence of an anionic surfactant additive in the solution (Оxy surfactant A1218). When extracting europium (III) compounds from a system with a sulphate background the best results were obtained at pH values of 8 and 10, as well as the addition of an anionic and, or cationic (Septa surfactant XEV70) surfactant. Chloride background showed the best conditions for the extraction of europium (III) at pH 7 with the addition of a non-ionic surfactant of PEO-1500 brand. The degree of extraction of europium is 98-99%.

A new serial sampler for collecting gas-tight samples from seafloor cold seeps and hydrothermal vents

This paper details the development and application of a new serial sampler capable of acquiring multiple deep-sea gas-tight fluid samples. It consists of a custom-made multiport sampling valve with six sampling cylinders distributed around it in a circle. The serial sampler can operate on the seabed to depths of 7000 m. Each cylinder has a sampling volume of about 160 ml and can maintain the sample at near in-situ pressure. It can be deployed by HOV or ROV to collect gas-tight fluid samples via remote or automatic operation. The new serial sampler was successfully field-tested at cold seep sites in the Gulf of Mexico and the South China Sea and also at hydrothermal vent sites on the Juan de Fuca Ridge and in the Indian Ocean.

Detection of trace metal ions in high-purity boric acid by online two-dimensional valve switching coupled with ion chromatography-inductively coupled plasma mass spectrometry

In this paper, a two-dimensional valve switching technique was established to detect 10 trace metal ions in high-purity boric acid by ion chromatography-inductively coupled plasma mass spectrometry (IC-ICPMS). The system consisted of a quantitative loop, a matrix capture column, an iminodiacetic acid cationic chelating column, an ion chromatography column, two sample valves and an inductively coupled plasma mass spectrometer. The iminodiacetic acid cationic chelating column coupled the metal ions in the sample with its carboxyl functional groups to separate them from the matrix boric acid solution, and then eluted the chelated metal ions into the ion chromatographic column and inductively coupled plasma mass spectrometer. The proposed method feasibly achieved an online, rapid and efficient detection of 10 trace ions in high-purity boric acid with the optimized experimental conditions (1.0 mol/L HNO3), such as loading solution, loading flow rate, type of eluent, concentration of the eluent, sample matrix, etc. The experimental data showed that this method had good linearity in the range of 0.01–2.0 μg/L for 10 metal ions, such as Cr, Fe, Ni, Co, V, Mn, Cu, Zn, Cd and Pb in high-purity boric acid samples, with a correlation coefficient greater than 0.998. The limit of detection (LOD, S/N = 3) and the limit of quantitation (LOQ, S/N = 10) were 0.001–0.023 μg/L and 0.003–0.077 μg/L, respectively. The relative standard deviation (RSD) of each element was less than 3.0% (n = 6) and the spiked recoveries ranged between 83% and 110%. This method could be proposed to be suitable for determination of trace metal ions in real samples.

Automated buffer preparation using quaternary valve in fast performance liquid chromatography for protein purification from a cell membrane

There is a great need for high-throughput protein purification to produce protein molecules for research and therapeutics. Although there have been significant advancements made in automated multi-step chromatography and preparative in-process design-of-experiment (DOE) capabilities in commercial fast performance liquid chromatography (FPLC) instruments, almost all commercial FPLCs rely on a binary buffer mixing system, which hinders automated buffer preparation. Nevertheless, current-generation FPLCs are equipped with a quaternary mixer designed for limited in-line buffer preparation and preparative pH scouting DOE experiments. We decided to leverage the quaternary mixing capability by extending and re-programming AkTA Avant’s quaternary valve into an automated in-process buffer preparation system to simplify automated purification requiring complex washing steps. We accomplished this by using two extra inlet valves, a sample valve, and versatile valve to split inputs of the quaternary valve into software-selectable stock solutions of pH buffers, salts, eluents, and additives. We also devised a new flow scheme to perform automated two-step chromatography using only one versatile valve. This was accomplished by using only stock parts and software to facilitate reproduction. To demonstrate the versatility and capability of the system, we purified a transmembrane protein that requires a detergent to stay soluble and needs an in-column, high-salt washing step to achieve high purity.

Distribution of Yeast Cells, Temperature, and Fermentation By-Products in White Wine Fermentations

Yeast inoculation from the tops of tanks is common in white wine fermentations. Our objective was to examine whether inhomogeneities occur in tanks following yeast addition from the top with and without brief stirring after inoculation. We investigated whether inhomogeneities affect fermentation kinetics and formation of acetaldehyde, acetic acid, and pyruvate in Riesling juices with low turbidity. Samples and temperatures were taken at multiple tank heights in pilot-scale (105 L) and industrial-scale (2500 and 7000 L) tanks to investigate the distributions of temperature, yeast, and fermentation products in tanks of different volumes and height-to-diameter ratios. When the tank was not stirred following inoculation, cell counts were higher in the upper tank section for multiple days. Fermentation started earlier at the top of the tank than at lower levels, as indicated by specific gravity measurements. The top and bottom of the tanks differed by up to 8.6°C and 0.040 in specific gravity. The inhomogeneities lasted four days in the 7000 L tanks. These results suggest slow yeast sedimentation and poor mixing in the downward direction during the early fermentation phase. During vigorous fermentation, all parameters were homogenously distributed. Brief stirring after yeast inoculation provided uniform conditions during the early fermentation phase, except for temperature differences due to natural stratification. Stirring also shortened the fermentation duration. The final pyruvate concentration was significantly lower when the yeast was stirred in, presumably due to better nutrient availability throughout the tank, reducing sulfur dioxide demand. No differences were observed in acetaldehyde and acetic acid concentrations. When yeast is not stirred in following inoculation, tank sampling valves and temperature sensors do not reflect the entire tank during the early fermentation phase, which will negatively affect process control.

Simulation analysis and experimental research of a sampling valve for the seafloor natural gas hydrates survey

A hydraulically actuated sampling valve is developed for the sub-sea situ pore-water and bottom seawater sampler. A unique pressure compensation design for the valve core is adopted in the sampling valve, which makes the sampling valve open or closure reliably under high pressure. Based on the developed sampling valve, a fluid sampler is manufactured, which includes three collecting bottles, one equilibrium bottle, one negative pressure bottle, one sampling valve, and a set of control unit. The simulation model of the developed sampler is established for the whole sampling process using the AMESim, and the dynamic and static characteristics of the sampling valve, check valve in the collecting bottle, negative pressure bottle are obtained numerically. And then, the simulation tests of the sampling valve are conducted at the simulated high pressure tank of 45 MPa. The developed sampling valve and sampler have been applied on the sub-sea situ pore-water and bottom seawater sampling system and tested at the situ pore-water and bottom seawater, which could also be widely used in marine and offshore oil and gas environmental investigation. This research will lay the foundation for the development of undersea tools for nature gas hydrate survey.

Individual and sequential effects of stirring, smoothing, and cooling on the rheological properties of nonfat yogurts stirred with a technical scale unit

Few studies have considered the impact of unit operations during stirred yogurt manufacture because their operational sequence is difficult to replicate at the laboratory scale. The aim of this study was to investigate the individual and sequential effects of stirring in the yogurt vat, smoothing, and cooling on the rheological properties of yogurts, using a technical scale unit simulating some industrial conditions. The yogurts were prepared from a milk mixture that was standardized to contain 14% total solids, 0% fat, and 4% protein, and then homogenized, heated (94.5°C, 5 min), and inoculated at 41°C with the same thermophilic lactic starter. The operating parameters under investigation were 2 stirring durations in the yogurt vat (5 or 10 min), 2 cooling systems (plate or tubular heat exchanger), and 2 smoothing temperatures (38°C for smoothing before cooling; 20°C for smoothing after cooling). Sampling valves were installed at critical points on the technical scale unit so that the effect of each operation on the properties of stirred yogurt could be quantified individually. Syneresis, apparent viscosity, firmness, and consistency were analyzed after 1 d of storage at 4°C. In general, as the yogurts moved through the technical scale unit, the properties of the yogurts (evaluated after 1 d) changed: viscosity increased but syneresis, firmness, and consistency decreased. The individual effects of the operations showed that smoothing and cooling, compared with stirring duration, made the greatest contribution in terms of modifying yogurt properties. The stirring parameters (5 or 10 min) had similar effects on the yogurts. The use of a plate heat exchanger promoted a decrease in syneresis, whereas a tubular heat exchanger had a greater effect in terms of increasing firmness and consistency. The type of cooling system had no effect on stirred yogurt viscosity. Smoothing at 38°C had a greater effect on the increase in firmness, whereas smoothing at 20°C contributed more to a decrease in syneresis and increases in viscosity and consistency. This study confirms that each unit operation has a defined effect on the rheological properties of a nonfat stirred yogurt, which also depends on the operation sequence.