Washing Solution Research Articles

Excel calculation of extraction separation in a full countercurrent cascade with decreasing distribution coefficients in the washing part

Liquid-liquid extraction is widely used in the hydrometallurgy of non-ferrous, rare and radioactive metals. The most difficult of the tasks solved using this method is the separation of elements with similar properties, in which, as a rule, it is necessary to obtain one or even both elements in pure form and with a high recovery. In most cases, this is achieved only in the complete countercurrent process, which is realized in a cascade consisting of two parts — extraction, which ensures the production of a worse extractable component (or a group of components) in a pure form in the aqueous phase (raffinate), and washing, which ensures additional extraction of a worse extractable component (or a group of components) into a raffinate or obtaining a better extractable component (or a group of components) in pure form in the organic phase (extract). However, the washing solution dilutes the original solution, which leads to a decrease in the concentrations of the components in the products. To reduce this negative effect, it is possible to reduce the volume of the washing solution by lowering the distribution coefficients of the separated components in the washing part of the cascade and again increasing them in the extraction part. This type of separation is called a full countercurrent process with decreasing distribution coefficients in the washing part. Since the organic phase from the extraction part of the cascade enters the washing part, and the aqueous phase from the washing part together with the initial solution enters the extraction one, when determining the required conditions for extraction separation (i.e., the necessary ratios of the extractant and washing solution flows to the flow of the initial solution, the number of stages extraction and washing parts of the cascade, the compositions of the products obtained – raffinate and extract), the full countercurrent cascade can be calculated only as a whole. As a result, the execution of the calculation is associated with a large amount of computation and takes a lot of time even when using modern computing means. An effective way to automate calculations is to create templates in the Excel© spreadsheet processor environment that allow, when switching to another extraction system, not to program the calculation again, but only to enter new initial data into the corresponding cells of the template. This article is devoted to the development of such a template for a complete countercurrent process with constant but different distribution coefficients of the components in the extraction and washing parts of the cascade.

Development of a multiprimer metabarcoding approach to understanding trophic interactions in agroecosystems.

To understand trophic interactions and the precise ecological role of each predatory species, it is important to know which arthropod and plant resources are used by generalist predators in agroecosystems. Molecular approaches, such as the use of high-throughput sequencing (HTS), play a key role in identifying these resources. This study develops a multiprimer metabarcoding approach for screening the most common trophic interactions of two predatory arthropods with contrasting morphologies, Rhagonycha fulva (Coleoptera: Cantharidae) and Anthocoris nemoralis (Hemiptera: Anthocoridae) collected from a peach crop. To reduce the time and cost of this metabarcoding approach, we first evaluated the effect of using two different predator-pools of different size (10 and 23 individuals of the same species). We also used our system to analyze the performance of one and two primer pairs in the same library. Our results show that the analysis of 23 individuals together with the use of two primer pairs in the same library optimize the HTS analysis. Using these best-performing conditions, we then analyzed the entire bodies of field-collected predators as well as the washing solutions used to clean the insect bodies. We were able to identify both gut content (i.e., diet) and external pollen load (i.e., on the insects' bodies). This study also demonstrates the importance of washing predatory insects' bodies prior to HTS analysis when the target species have a considerable size (>10 mm) and hairy structures. This metabarcoding approach has significant potential for the study of trophic links in agriculture, revealing expected and unexpected trophic relationships.

Integrated soil washing and bioreactor systems for the treatment of hexachlorocyclohexane contaminated soil: A review on enhanced degradation mechanisms, and factors affecting soil washing and bioreactor performances

Investigations about the remediation of Hexachlorocyclohexane (HCH), a persistent organic pollutant of global concern, have been extensively reported to treat the HCH contaminated soil. The difficulty arising due to desorption and long ageing procedures of this hydrophobic organic compound in the soil, make it necessary to exploit techniques like soil washing or addition of surfactants, for enhancing the mass transfer rate of hydrophobic compounds. However, this technique gives rise to the generation of a large quantity of waste solution containing the pollutant and various other toxic substances. Moreover, it is challenging to deal with the complex soil washing solution, and thus a follow-up treatment of such washing solution is essentially required before its discharge. This follow-up treatment could be the bioreactor system to efficiently treat the pollutant in the wash solution, thereby reducing the amount of contaminated soil that has to be treated. Among many suggested remediation methods and treatment technologies, integrated soil washing and post-treatment with the bioreactor system could be an environmentally viable method for the remediation of HCH contaminated sites. This review focuses on the soil washing procedures applied so far for the HCH contaminated soil and various factors affecting the efficiency of separation of the target pollutant. Furthermore, the environmental and reactor design-related factors are also discussed for degradation of HCH in the reactor system. Finally, advantages and environmental feasibility of this proposed combined technology and the challenges that need to be encountered are envisaged.

Remediation of chromium contaminated soil by soil washing using EDTA and N-acetyl-L-cysteine as the chelating agents

The use of chelating agents in soil washing has been known to be an efficient, eco–friendly, and inexpensive treatment process for the removal of heavy metal contamination. In this study, statistically designed lab-scale soil washing experiments were carried out using two chelating agents i.e., ethylene diamine tetraacetic acid (EDTA) and N-acetyl-L-cysteine (NAC). The effects of pH, contact time and dosage of wash solution on chromium (Cr+6) removal efficiency (RE) was investigated and optimized using response surface methodology (RSM). The ANOVA analysis of the experimental design for both the chelating agents revealed that pH is the key influencing parameter in Cr+6 removal. The optimum conditions were found to be: pH - 5.5, contact time - 216 h, dosage of EDTA - 4128 mg/kg and dosage of NAC - 300 mg/kg. The projected Cr+6 RE under these optimum conditions was 14.3% and 65.7%, for EDTA and NAC, respectively. The results from this investigation indicated that soil washing with NAC could be a better alternative to EDTA for Cr+6 removal from soil.

Design and development of a novel double-chamber syringe concept for venous catheterization

This paper presents the optimization process for the development of an innovative double chamber syringe. Several aspects are involved such as design, functionality, fluid-structure interaction and friction between solids.To assist in the development of this medical device, a numerical based methodology was developed and validated in order to predict the syringe´s functionality, as well as its production by injection molding. The mechanical and flow behavior, during the filling and administration of medicine and washing solutions, were numerically modelled using the commercial software ABAQUS and FLUENT, respectively. The injection molding process was analyzed using the software MOLDFLOW. The aim was to evaluate the feasibility of the proposed concept in terms of mechanical design, fluid flow and production process behavior. By highlighting critical design issues in this way, it was possible to identify promising geometric changes and, consequently, optimize iteratively the syringe's design, until all the defined requirements are fulfilled.This iterative process based on numerical simulations proved to be a powerful tool for product development that generated fast and accurate results without the need to produce multiple prototypes.

Standardizing Patient-Derived Organoid Generation Workflow to Avoid Microbial Contamination From Colorectal Cancer Tissues.

The use of patient-derived organoids (PDO) as a valuable alternative to in vivo models significantly increased over the last years in cancer research. The ability of PDOs to genetically resemble tumor heterogeneity makes them a powerful tool for personalized drug screening. Despite the extensive optimization of protocols for the generation of PDOs from colorectal tissue, there is still a lack of standardization of tissue handling prior to processing, leading to microbial contamination of the organoid culture. Here, using a cohort of 16 patients diagnosed with colorectal carcinoma (CRC), we aimed to test the efficacy of phosphate-buffered saline (PBS), penicillin/streptomycin (P/S), and Primocin, alone or in combination, in preventing organoid cultures contamination when used in washing steps prior to tissue processing. Each CRC tissue was divided into 5 tissue pieces, and treated with each different washing solution, or none. After the washing steps, all samples were processed for organoid generation following the same standard protocol. We detected contamination in 62.5% of the non-washed samples, while the use of PBS or P/S-containing PBS reduced the contamination rate to 50% and 25%, respectively. Notably, none of the organoid cultures washed with PBS/Primocin-containing solution were contaminated. Interestingly, addition of P/S to the washing solution reduced the percentage of living cells compared to Primocin. Taken together, our results demonstrate that, prior to tissue processing, adding Primocin to the tissue washing solution is able to eliminate the risk of microbial contamination in PDO cultures, and that the use of P/S negatively impacts organoids growth. We believe that our easy-to-apply protocol might help increase the success rate of organoid generation from CRC patients.

A closed-loop system to recycle rare earth elements from industrial sludge using green leaching agents and porous β-cyclodextrin polymer composite

Industrial sludge is classified as hazardous waste as well as a resource of valuable metals and needs to be adequately treated for the sake of the environment and economy. This study reports a green approach for extracting and purifying rare earth elements (REEs) from industrial sludge using environmentally friendly washing solutions ((NH4)2SO4, N, N-Bis(carboxymethyl) glutamic acid (GLDA), tetrabutylammonium bromide ionic liquid (TBAB), and water) and a porous β-cyclodextrin polymer composite (PCDP-M-SHM) respectively. The results showed that there is no significant difference between used extracting solutions. However, the speciation study indicated that most REEs in the sludge sample were bounded to a water-soluble fraction. Therefore, for economic reasons, water was used for further studies. Furthermore, the recycling efficiencies after the purification of leached REEs with PCDP-M-SHM were in the range of 76.0 % (Gd) to 87.3% (Pr), except for Ce (8.29%).Moreover, cost evaluation and sensitivity analysis studies were performed to investigate the applicability of the reported method at the industrial level. The cost evaluation results estimated $3676 as the cost of processing 1 ton of sludge with revenue of $710/ton of sludge. Finally, the sensitivity analysis test affirmed the profitability to depend on the cost of PCDP-M-SHM. Based on the future market price of REEs, the proposed closed-loop recycling approach could be a promising green solution for environmental problems related to mining, processing, and conservation of REEs resources as well as industrial sludge disposal.

Removal behavior and mechanisms of cadmium and lead by coupled ethylenediaminetetraacetic acid washing and electrochemical reduction: influence of current conditions.

Ethylenediaminetetraacetic acid (EDTA) washing has been used extensively to remediate heavy metal-contaminated soils. Electrochemical reduction treatment of spent washing solution is an effective method of EDTA regeneration. However, at present, these two technologies are usually regarded as two independent treatment processes. This research raised a new heavy metal-contaminated soil treatment strategy-a combination technique of coupled EDTA washing and electrochemical reduction. We speculated that the combination of EDTA washing and electroreduction treatment could improve the efficiency of Cd and Pb removal from contaminated soil. In this study, the removal performance and mechanisms of Cd and Pb under different current conditions were investigated based on a coupling of EDTA washing and electrochemical reduction. The combination technique can increase Cd and Pb removal efficiencies by 13.37-15.24% and 14.91-27.05%, respectively, compared with EDTA washing alone. Sequential extraction analysis showed that the reducible fraction improved metal removal efficiency. The percentage of metal removed increased with an increased current value and EDTA concentration. In addition, pulse current mode removed more Cd and Pb than continuous current, although the difference was not significant (p > 0.05). However, pulse current could effectively eliminate the cathodic hydrogen evolution reaction, resulting in a further heavy metal deposition at the cathode. The combination technique exhibited enhanced removal efficiency due to EDTA regeneration in the suspension and the cathodic reduction reaction. The most cost-effective treatment in 48h was a pulse current mode of 32min on/16min off-32mA-EDTA-10mM, where 47.56% of Cd and 77.00% of Pb were removed from the soil with an electric energy consumption of 8.24 Wh.

Determination of chlorpropham residues in animal-derived foods by solid phase extraction and ultra-high performance liquid chromatography-tandem mass spectrometry

建立了固相萃取-超高效液相色谱-串联质谱法(SPE-UHPLC-MS/MS)测定动物源食品中氯苯胺灵残留的分析方法。动物源食品经乙腈溶液提取、正己烷脱脂、ProElut PLS固相萃取柱富集净化,采用C18色谱柱进行分离,以0.2%(v/v)甲酸水溶液和乙腈为流动相进行梯度洗脱,采用电喷雾电离、正离子模式扫描,多反应监测模式(MRM)检测,基质匹配标准曲线外标法定量。研究通过对不同填料的固相萃取柱的考察,最终选择了ProElut PLS固相萃取柱,其能对动物源食品复杂基质中的氯苯胺灵进行有效富集和净化;通过考察3种规格的C18柱对氯苯胺灵的保留能力和出峰效果,选择了Agilent ZORBAX SB-C18(150 mm×2.1 mm, 5 μm)作为氯苯胺灵的分离色谱柱;通过考察氯苯胺灵在正负两种质谱电离模式下的响应情况,选择了正离子模式,确定氯苯胺灵一级质谱准分子离子和相应的碎片离子。结果表明:氯苯胺灵在0.5~100.0 μg/L范围内呈良好的线性关系,相关系数(r2)均不低于0.9929;方法定量限(LOQ)为3 μg/kg(S/N≥10);以猪肉、牛奶、牛肉、鸡肉、鸭肉、鸡蛋、鸡胗、鸭蛋、猪腰、猪肝、牛肝、羊肉、鸭胗共13种动物源食品为基质,在0.003、0.006、0.060 mg/kg添加水平下,氯苯胺灵的平均回收率为74.9%~97.6%,相对标准偏差(RSD)为2.9%~9.5%(n=6)。本方法前处理简便易行、基质干扰小、灵敏度高、准确性高,适用于多种动物源食品中氯苯胺灵的定性和定量检测。

INCREASING THE CLEANING INTENSITY IN THE RUMBLING DRUM

Cleaning of fasteners and small parts at repair and machine-building enterprises is carried out in rumbling drums at a constant speed. The quality of cleaning is low. Searching for new cleaning techniques is an urgent task. (Research purpose) The research purpose is increasing the cleaning intensity in a rumbling drum, performing a complex movement in a bath with a washing solution. (Materials and methods) The article presents an upgraded washing machine with a complex drum movement. The mathematical justification of the installation design was presented. The article describes the installation scheme with a complex movement of the rumbling drum. It was proposed to place panels with brushes on the sides of the drum from the inside, which will allow damping the blows of the contents against the walls. (Results and discussion) The movement of the cleaned products and the filler inside the rotating rumbling drum depends on its rotation frequency. At a low rotational speed, there is a cascade movement. While the rotation speed increases, the contents of the drum are aligned and pressed against its walls and the relative movement stops. The maximum speed and acceleration are many times greater than in the known drums. The cleaning solution is fed into the drum without a pump due to the waves formed in front of the moving drum. (Conclusions) Due to the change in the movement of the products inside the rolling drum, the intensity of cleaning increases. The design of the installation makes it possible, with low energy costs for the drum drive, to significantly intensify the cleaning of products. The duration of cleaning is significantly reduced and depends on the type of products and contamination of their surfaces.

Determination of atypical antipsychotics in human plasma by UPLC-UV with polystyrene nanofibers as a solid-phase extraction sorbent.

A novel extraction procedure was developed using polystyrene (PS) nanofibers as a solid-phase extraction sorbent to collect atypical antipsychotics (AAPs) from human plasma. The extraction targets were then monitored by ultra high performance liquid chromatography with an ultraviolet detector system. Parameters affecting extraction efficiency such as fiber packing amount, wash solution, and eluted solvent were investigated. Under optimized conditions, the linear range of seven AAPs was 1–50 μgmL−1 (R2 > 0.996). Inter-day and intra-day relative standard deviations were less than 15.1%, and relative error varied from −17.1% to 12.0%. Furthermore, 50.5–79.3% extraction recoveries were obtained. The lower limit of quantification was 1 μg mL−1, and detection limit was 0.5 μg mL−1. The method developed in this study may be applied to simultaneous quantification of seven AAPs in human plasma due to its simplicity, selectivity, and efficiency.

Possibility of mechanical transmission of parapoxvirus by houseflies (Musca domestica) on cattle and sheep farms.

Parapoxvirus (PPV) causes papular stomatitis and contagious pustular dermatitis in ruminants worldwide. The virus is generally transmitted through close contact with skin lesions containing PPV in infected animals and indirectly through PPV-contaminated materials. PPV-infected animals frequently do not show clinical signs and the route of PPV transmission is sometimes unclear. In this study, the possibility of mechanical transmission of PPV by houseflies (Musca domestica) was investigated using polymerase chain reaction (PCR) gene surveillance. Samples were collected from cattle, sheep, barn environments, direct wash solution of the body surface of houseflies, and indirect wash solution of the body surface and feces of the flies. Bovine papular stomatitis virus, pseudocowpox virus, and orf virus were detected in the oral cavity and body surface of cattle and sheep without clinical signs of PPV infection or barn environments; PPV was considered to have been retained on the farm. PPVs were also detected in the direct wash solution of the body surface of houseflies, and the indirect wash solution of the body surface and feces of the flies. The viral sequence determined from the indirect wash solution of the body surface and feces of the flies was identical to that determined from the body surface of cattle and barns. These results suggested that houseflies may mechanically transmit PPV to both cattle and sheep.

Modeling desorption and adsorption kinetics of reactive red 195 in washing microenvironment

The faded-on stains of cotton clothes are a common daily phenomenon. The desorption and adsorption of reactive dyes are theoretically responsible for the faded-on stains on cotton clothes in the washing microenvironment, especially when the light color cotton fabrics ( LCFs) are washed together with the cotton fabrics dyed in highly saturated color ( CFSCs). However, the effects of washing parameters on the desorption and adsorption kinetics of reactive dyes and the mitigation of faded-on stains in the washing microenvironment through washing parameter optimization are poorly understood. This study thoroughly discusses the desorption and adsorption behaviors of reactive red 195 in the washing microenvironment from the inhibition of color transfer. Firstly, CFSCs and LCFs were prepared by using reactive red 195 and cotton fabrics. Secondly, the effects of washing parameters, washing temperature, washing liquor ratio, and washing solution pH, on the dye desorption and adsorption rate were studied with the simulated washing device ( SWD), followed by the response surface analysis of washing parameters. Thirdly, the modeling of desorption and adsorption kinetics and velocity were detailed. Finally, the model of dye desorption and adsorption was validated in a drum washing machine ( DWM). The results are helpful for the design of scientific washing procedures to curb the faded-on stains of cotton clothes effectively.

ИНТЕНСИФИКАЦИЯ ПРОЦЕССА ОЧИСТКИ ДЕТАЛЕЙ В ПОГРУЖНЫХ МОЕЧНЫХ МАШИНАХ

An analysis of the working conditions of agricultural machinery showed that the main contaminants of parts include a combination of soil residues with plant and other organic materials and a mixture of petroleum products of various origins. To identify the most efficient and cost-effective mode for cleaning parts, the authors conducted an experiment that takes into account three factors: the duration of washing, the temperature of the washing solution, and the concentration of the aqueous solution of detergent components. The optimization criterion is the amount of washed out contamination. The authors designed a matrix for the implementation of the full-factorial experiment plan. Samples in the form of a square tube with a size of 50 × 50 mm and a length of 50 mm were cleaned using a submersible washing machine in the form of a small-sized ultrasonic bath Specos V-100. A solution consisting of sodium carbonate and a mixture of surfactants in a ratio of 9:1 was used as a detergent. The modes of ultrasonic cleaning were changed in accordance with the variation of three factors: cleaning duration – from 5 to 15 minutes, washing solution temperature – from 40 to 80°C; concentration of the aqueous solution of detergent components – from 5 to 25 g/l. The reproducibility of the experimental results was confirmed using the Cochran test. The significance of the regression coefficients was determined using Student’s t-test. The model was validated using the Fisher criterion. Based on the regression equation, the authors determined response surfaces, in which the dependences are extremely close to linear. It is concluded that with washing duration of 12 minutes, a washing solution temperature of 70°С, and a concentration of the aqueous solution of detergent components of 20 g/l, the amount of washed out contamination is maximum.

Coupling of Desorption of Phenanthrene from Marine Sediments and Biodegradation of the Sediment Washing Solution in a Novel Biochar Immobilized–Cell Reactor

Coupling of Desorption of Phenanthrene from Marine Sediments and Biodegradation of the Sediment Washing Solution in a Novel Biochar Immobilized–Cell Reactor

Treatment dependent sodium-rich Prussian blue as a cathode material for sodium-ion batteries.

In the preparation of Prussian blue analogs (PBAs), Na+ loss and Fe2+ oxidation take place when washing with water. Sodium-rich PBAs were prepared with sodium ascorbate aqueous solution as the washing solution, which can suppress the Na+ loss and Fe2+ oxidation. As the cathode of sodium-ion batteries, it exhibited excellent electrochemical performance.

Survival of Salmonella Typhimurium and Escherichia coliO157:H7 on blueberries and impacts on berry quality during 12 weeks of frozen storage after washing with combinations of sodium dodecyl sulfate and organic acids or hydrogen peroxide

AbstractSalmonella spp. and Escherichia coli are well tolerant of freezing. This study was to investigate survival of the foodborne pathogens during storage at −18 ± 2°C for 12 weeks on blueberries after washing with: 500 ppm acetic acid plus 5,000 ppm sodium dodecyl sulfate (SDS) (AA/SDS), 20 ppm peroxyacetic acid plus 5,000 ppm SDS (PPA/SDS), or 200 ppm hydrogen peroxide plus 5,000 ppm SDS (H2O2/SDS), when compared with findings from no wash, or wash with water, 80 ppm PPA or 200 ppm chlorinated water. Following a 60 s contact with one of the three new solutions, the treatments showed 3.3–3.9 log10 CFU/g reductions in Salmonella Typhimurium and E. coli O157:H7 counts. After 2 weeks of frozen storage, 3.9–4.2 log10 CFU/g reductions of Salmonella and E. coli were observed. After 12 weeks of frozen storage, Salmonella and E. coli survivors were below detection limits (0.39 log10 CFU/g) in berries washed with new solutions. The frozen storage had a significant impact (p < .05) on microbial counts of both treated and nontreated blueberries. Although none of these washings decreased the total phenolic and anthocyanins contents and apparent quality at time 0, frozen storage caused significant damage on the texture of both treated and nontreated blueberries. Interestingly, no significant decrease in the total phenolic, anthocyanins content, and apparent quality was observed during the 12‐week frozen storage. The counts of total bacteria, yeasts, and molds decreased throughout storage for treated and untreated berries. This demonstrates that the three wash solutions enhance the safety of frozen berries.

INVESTIGATION OF PULSE VIBRATION OF THE PERIODICALLY WORKING INJECTOR OF THE MILKING WASHING SYSTEM

As a result of the analysis of technical and technological support of washing of milking installations it is established that the most effective are circulating systems of washing with regulated formation of a stopper mode with use of air injectors on the basis of automatic control. The consequences of periodic operation of the injector is the phenomenon of hydraulic shock, which is caused by a sudden change in the phase distribution of the flow of two-phase washing solution. This leads to a sudden change in the momentum of the two-phase washing solution, causing a pressure wave moving through the system. This pressure wave can lead to the destruction of milk deposits on the walls of the milk line, as well as to possible damage to the equipment of the milk system. The aim of the study is to increase the efficiency of the milking system flushing system by using pulsed vibration of a periodically operating injector. As a result of numerical simulation of the process of washing the milk line of the milking parlor using an injector in the software package STAR-CCM + was determined by the dynamics of changes in vacuum pressure at a distance from the injector (p (0 m), p (1 m), p (2 m), p ( 3 m), p (4 m), p (5 m)) and the dynamics of changes in the content of components of the multiphase medium (washing solution αf, air αg, milk αm) for four options: the injector is constantly closed, the injector is constantly open and the injector is periodically opened (1 s and 9 s) and closes (1 s and 9 s). It is established that the use of a periodic injector allows to reduce the milk content in the milk line faster and by a larger value, which indicates a better washing process. The addition of the physical-mathematical apparatus of the hydraulic shock phenomenon for a periodically operating air injector of the flushing system allowed to establish that the rate of pressure change depends on the velocities and concentrations of phases of two-phase washing solution, ie its flow regime and shock wave propagation velocity. Therefore, the rate of pressure change Δp / Δt is chosen as a criterion for the action of hydraulic shock.

Preparation and evaluation of molecularly imprinted polymers as selective SPE sorbents for the determination of cathinones in river water

In this study, a series of molecularly imprinted polymers (MIPs) were synthesised using (1R,2S)-(–)-ephedrine or (1S,2S)-(+)-pseudoephedrine as template, methacrylic acid as functional monomer and ethylene glycol dimethacrylate as cross-linking agent. A highly selective and sensitive method using the best performing MIP as sorbent in the solid-phase extraction (SPE) followed by liquid chromatography-high resolution mass spectrometry was established for the enantiomeric determination of five cathinones in river water samples. The SPE parameters (sample loading volume and pH, washing and elution solutions) were optimised so that recoveries and selectivities for the analytes were high. The enantioselectivity of MIPs towards the enantiomers of the analytes during the SPE process was also investigated. Under optimal conditions, the method developed provided satisfactory recoveries ranging from 67.6 to 83.2 % with a negligible matrix effect ranging from −5.5 to 1.8 %. The detection limits ranged from 0.3 to 0.8 ng/L and quantification limits ranged from 1.0 to 2.0 ng/L. The application of the method to the analysis of the river water samples indicated that methedrone and butylone were present at low concentration levels in river water samples.

Effects of the Washing Time and Washing Solution on the Biocompatibility and Mechanical Properties of 3D Printed Dental Resin Materials.

Three-dimensional (3D) printing technology is highly regarded in the field of dentistry. Three-dimensional printed resin restorations must undergo a washing process to remove residual resin on the surface after they have been manufactured. However, the effect of the use of different washing solutions and washing times on the biocompatibility of the resulting resin restorations is unclear. Therefore, we prepared 3D-printed denture teeth and crown and bridge resin, and then washed them with two washing solutions (isopropyl alcohol and tripropylene glycol monomethyl ether) using different time points (3, 5, 10, 15, 30, 60, and 90 min). After this, the cell viability, cytotoxicity, and status of human gingival fibroblasts were evaluated using confocal laser scanning. We also analyzed the flexural strength, flexural modulus, and surface SEM imaging. Increasing the washing time increased the cell viability and decreased the cytotoxicity (p < 0.001). Confocal laser scanning showed distinct differences in the morphology and number of fibroblasts. Increasing the washing time did not significantly affect the flexural strength and surface, but the flexural modulus of the 90 min washing group was 1.01 ± 0.21 GPa (mean ± standard deviation), which was lower than that of all the other groups and decreased as the washing time increased. This study confirmed that the washing time affected the biocompatibility and mechanical properties of 3D printed dental resins.