Acetate Aqueous Solution Research Articles

Analysis of ginseng root and leaf by multiple columns and detections liquid chromatography

A multiple columns and detections liquid chromatography system, including size exclusion chromatography (SEC) and reversed phase liquid chromatography (RPLC), for the analysis of macromolecules and micromolecules in ginseng root and leaf was developed. The columns were connected by two switching valves. Macromolecules were separated on a SEC column (TSK gel SuperMultipore PW-H column, 6 mm× 150 mm, 8 μm) by isocratic elution of 50 mM ammonium acetate aqueous solution, 0.3 mL/min of flow rate and detected by evaporative light scattering detection (ELSD). Micromolecules were analyzed on a Poroshell RP column (Agilent Poroshell 120 SB-Aq column, 4.6 mm × 50 mm, 2.7 µm) with gradient elution of water and acetonitrile, 0.6 mL/min of flow rate and detected by ultraviolet detection (UV). As a result, in the macromolecules chromatogram of ginseng root sample showed two main peaks while only one major peak for ginseng leaf. For micromolecules analysis, 17 compounds (3 nucleosides + 14 saponins) and 17 compounds (3 nucleosides + 1 flavonoid + 13 saponins) were found in ginseng root and leaf, respectively. The developed method is helpful for the quality evaluation of ginseng root and leaf.

Kinetics of chemical absorption of carbon dioxide into aqueous calcium acetate solution

AbstractIncreasing energy demand in the world leads to more electricity generation mainly at fossil fuel power plants. Greenhouse gases are thus produced and mostly emitted to the atmosphere directly, resulting in global warming and climate change. Carbon dioxide is believed to be a main pollutant among greenhouse gases responsible from global warming. Conventional systems using mostly amine solutions to capture carbon dioxide at the source have some disadvantages, and alternatives are constantly being searched. In this work, a benign system of aqueous calcium acetate solution was investigated for this purpose. Calcium acetate is easy to produce, relatively cheap, environmentally friendly, nonhazardous, and noncorrosive. These properties make it a great alternative for use in capturing carbon dioxide. This absorption process is accompanied by chemical reaction. Therefore, the reaction kinetics needs to be investigated before its use in absorbers. A stirred cell reactor was used in the experiments using aqueous calcium acetate solution of different concentrations (2‐20% w/w) and different carbon dioxide concentrations in gas mixtures (4.5‐100% v/v dry carbon dioxide) at temperatures ranging from 286 to 352 K. The Gibbs free energy change for the overall reaction between carbon dioxide and aqueous calcium acetate solution was found to be –2.75 kJ/mol that shows the reaction is exergonic and occurs spontaneously. It was also found out that the reaction is pseudo–first order with respect to carbon dioxide which was also proven by calculating the Hatta number. Activation energy and Arrhenius (frequency) constant were also determined experimentally.

Analysis of four preservatives in beverages and instant noodle samples by high performance liquid chromatography-ultraviolet detection coupled with magnetic solid phase extraction based on metal-organic frameworks

Magnetic amino functionalized metal-organic frameworks (MOFs) were prepared by a simple stirring and blending process. The obtained composites had good magnetic and thermal stability with a large specific surface area, and were used for the extraction of four preservatives with different polarities (benzoic acid, sorbic acid, propyl p-hydroxybenzoate and butyl p-hydroxybenzoate) in soda water, vitamin beverage and instant noodle cake samples. After optimizing the conditions for magnetic solid phase extraction (MSPE) and desorption, the four preservatives were analysed by a high performance liquid chromatography-ultraviolet detection (HPLC-UV) method. The analytes were separated on a Purospher® STAR LP C18 column (250 mm×4.6 mm, 5 μm). Methanol and 10 mmol/L ammonium acetate aqueous solution (50:50, v/v) were used as the mobile phases with gradient elution. The limits of detection of the four preservatives were 0.51-1.89 μg/L. The recoveries of the target preservatives were 72.2%-109% in the soda water, vitamin beverage and instant noodle cake samples. The method is simple, rapid, accurate and reliable, and is suitable for the analysis of preservatives with different polarities in beverages and foods. The method can provide an effective technology for food safety and quality control.

Characterization and physical properties of electrospun gelatin nanofibrous films by incorporation of nano-hydroxyapatite

In this study, the gelatin/nano-hydroxyapatite (n-HAP) composite nanofibrous films were fabricated by electrospinning. The gelatin/n-HAP mixtures in acetic aqueous solutions as the spinning dispersions showed a shear thinning behavior, and the apparent viscosity increased with the increasing n-HAP content. However, the average diameter of the gelatin nanofibers decreased from 516 to 510, 458 and 403 nm after the addition of 10%, 25% and 50% n-HAP, due to the decreased entanglement density. The EDS and TEM analysis indicated that n-HAP was uniformly dispersed within the nanofibers. As indicated by the FTIR results, the hydrogen bonding formed between gelatin and n-HAP resulted in the conformational transition of gelatin from β-sheet to turns. The water contact angle and XPS analysis suggested that the incorporation of n-HAP favored the wettability of the electrospun nanofibrous films, which was ascribed to the rough fiber surface and higher ratio of polar groups on the surface. The incorporation of 10% n-HAP did not affect the mechanical strength significantly, but the higher ratios of n-HAP led to the brittle and fragile property of the electrospun films. In addition, the water barrier property of the gelatin nanofibrous film was significantly improved by the addition of n-HAP. These results suggest that the surface wettability, mechanical strength and water barrier property of the electrospun gelatin nanofibrous films may be tuned by the incorporation of nano-hydroxyapatite.

Simultaneous characterisation of multiple Mahonia fortunei bioactive compounds in rat plasma by UPLC–MS/MS for application in pharmacokinetic studies and anti-inflammatory activity in vitro

The stems of Mahonia fortunei (MF) are commonly used in Chinese Traditional Medicine and contain multiple bioactive compounds, including 3,4,5-trimethoxyphenol-1-O-β-d-glucopyranoside (1), 5-hydroxypicolinic acid methyl ester (2), acortatarin A (3), syringic acid (4), 9-epi-acortatarin A (5), vomifoliol (6), corydaldine (7), noroxyhydrastinine (8), columbamine (9), jatrorrhizine (10), palmatine (11), berberine (12) and schisandrin (13). The pharmacokinetics of these 13 compounds in the rat plasma were assessed using a novel sensitive, rapid, and specific UPLC-ESI-MS/MS method after oral administration of an aqueous extract of MF stems. Carbamazepine was employed as the internal standard (IS) and all samples were precipitated with acetonitrile. Chromatographic separation was performed on a C18 column using a gradient elution at 0.3 mL/min, with the mobile phase consisting of acetonitrile and 0.06 % formic acid and 5 mM ammonium acetate aqueous solution. The calibration curves showed satisfactory linearity in the examination area (r2 ≥ 0.99). The accuracy, precision, extraction recovery, matrix effect, and stability were within acceptable ranges. The method successfully assessed the pharmacokinetics of these 13 compounds. In vitro, compound 12 exhibited potent inhibitory activity against production of nitric oxide (NO) in the RAW264.7 cell line when stimulated by lipopolysaccharide (LPS), while compounds 7, 12, and 13 were the most potent inhibitors of NO production in the BV2 cell line when stimulated by LPS. The IC50 values of compounds 7, 12 and 13 were 42.81, 20.55 and 22.74 μM. We conclude that these compounds have promise for clinical application, although their synergistic action may be more effective than that by any single compound alone.

Supported liquid membrane for acetic acid extraction: Screening of membrane support preparation factors

It is essential to remove acetic acid from the biomass hydrolysate during the biorefinery process. The product yield can be effected by the acetic acid due to it inhibition to the microorganism used during the fermentation. Supported liquid membrane (SLM) can be used to remove the acetic acid. The membrane support plays important role in the SLM process. However, due to the use of the commercial membrane support, lack of studied was conducted on the fabrication of custom made membrane support for the SLM process. In the current study, two level full factorial design was employed to screen three fabrication factors during preparation of polyethersulfone-graphene membrane support via vapor induced phase separation technique. The factors screened were temperature of water bath (A) (30-60 °C), exposure time (B) (10-60 s) and air humidity (C) (70-90 RH%). The response was evaluated based on the extraction percentage of the acetic acid from 10 g/L aqueous acetic acid feed solution. All three main factors were significant to the SLM performance. Air humidity factor (C) gave the highest contribution of 28.96% among the main factors. In term of the interaction between factors, water bath temperature (A) and exposure time (B) give the most significant effect with 45.01% percentage of contribution. The highest extraction percentage of the acetic acid using SLM system was 75.95% using the membrane prepare at 30 °C water bath temperature, 10 s exposure time and 70% air humidity.

Electrochemical synthesis of AgNP and mechanical performance of AgNP-EG coatings on soft elastomer

Silver nanoparticles (AgNP) are being used extensively in medical and modern age stretchable and flexible electronics applications. In this article, we describe easy, cost-effective, and scalable synthesis of AgNP using electrolysis of pure silver metal in aqueous silver acetate solution. Size measurements and structural characterizations of the nanoparticles were performed using scanning electron microscopy coupled with image analysis and X-ray diffraction techniques, respectively. As-prepared nanoparticles were dispersed in pure ethylene glycol (EG) in a concentration of 50 wt%. The dispersion was coated on a soft, sticky, stretchable, and flexible elastomeric substrate polydimethylsiloxane (PDMS). Finally, the stretchability and flexibility tests on AgNP-EG/PDMS laminate were performed. The as-fabricated AgNP-EG/PDMS laminate is capable of stretching up to 18% without electrical failure. It was also found to remain electrically conductive when bent on curved surfaces. This behavior indicates that the AgNp-EG/PDMS laminate has good stretchability and flexibility and can be used as an electrically conductive platform for stretchable and flexible electronics.

Development of a UHPLC-MS/MS method for the quantification of ilaprazole enantiomers in rat plasma and its pharmacokinetic application

In Korea and China, ilaprazole is a widely used proton pump inhibitor in the treatment of gastric ulcers. In this study, a specific and sensitive LC-MS/MS method has been developed and validated for the quantification of ilaprazole enantiomers in the rat plasma, using R-lansoprazole as the internal standard. The enantioseparation was achieved on a CHIRALPAK AS-RH column (4.6 mm × 150 mm, i.d. 5 μm), with a mobile phase composed of 10 mM ammonium acetate aqueous solution and acetonitrile (60:40, V/V), at a flow-rate of 0.5 mL/min. The method was validated over the concentration range of 0.5–300 ng/mL for both, R- and S -ilaprazole. The lower limit of quantification was 0.5 ng/mL for both enantiomers. The relative standard deviation (RSD) of intra- and inter-day precision of R-ilaprazole and S-ilaprazole was less than 10.9%, and the relative error accuracy (RE) ranged from −0.5%–2.0%. Finally, the method was successfully evaluated in rats in a stereoselective pharmacokinetic study of the ilaprazole racemate.

Concentration of aroma compounds by pervaporation process using polyvinyl chloride membrane

AbstractThe organoleptic properties of beverage products have an important role in consumption and commercial success. Nowadays aroma recovery with high efficiency is an important process. Hydrophobic pervaporation is an alternative process for the recovery of aroma compounds in the food industry. The purpose of this study was to determine the effects of operation temperature, feed concentration, and driving force on the recovery of different aroma compounds such as propyl acetate, pentyl acetate, and octyl acetate by pervaporation. Pervaporation was operated using a Polyvinyl Chloride hydrophobic membrane. As the process temperature and the feed concentration increased, the flux increased, but separation factor values of binary aqueous solutions of the aroma components propyl acetate, pentyl acetate, and octyl acetate decreased. Polyvinyl Chloride possessed a higher separation factor value for propyl acetate than octyl acetate and pentyl acetate. This situation was also confirmed with swelling tests and solubility parameters. Low‐swelling degree results in a high separation factor. The highest separation success was observed for propyl acetate. The flux and separation factor of propyl acetate were obtained as 1.57 kg m−2 h−1 and 158, respectively. It has been found that the pervaporation is an efficient process for aroma recovery from water and that the polyvinyl chloride membrane exhibits good separation performance from the removal of propyl acetate, pentyl acetate, and octyl acetate from the water.

Simultaneous Determination of Caffeine, Taurine and Five Water-Soluble Vitamins in Tobacco Products by HPLC–MS/MS

The simultaneous determination of caffeine, taurine and five water-soluble vitamins (B1, B2, B3, B9, and B12) in tobacco products by high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) was established in this work. Tobacco powders of sampled tobacco products were extracted with water and then filtered. The filtrates were separated on an Agilent Eclipse XDB-C18 (2.1 mm i.d × 150 mm, 3.5 μm) column using methanol: ammonium acetate aqueous solution (10 mM) as the mobile phase at a flow rate of 0.3 mL min−1 using the gradient elution mode. These analytes were detected by electrospray ionization–tandem mass spectrometry (ESI–MS/MS) using a multiple reaction monitoring method. Under the optimized conditions, the separation of caffeine, taurine and five water soluble vitamins was achieved within 12 min. The linear ranges of caffeine, taurine and vitamins B1, B2, B3, B9, and B12 were 2.000–100.0, 0.3316–3316, 0.1248–249.6, 1.600–160.0, 0.5990–29.95, 0.3150–31.50, and 0.2246–2246 μg L−1, respectively, with linear correlation coefficient greater than 0.997. The detection limits (S/N = 3) of caffeine, taurine and vitamins B1, B2, B3, B9, and B12 were 0.445, 0.079, 0.031, 0.400, 0.179, 0.079, and 0.066 μg L−1, respectively. The precisions for intra-day (n = 11) and inter-day (n = 5) were 0.09–2.23% and 0.11–2.52%, respectively. The recoveries of these seven analytes in the spiked tobacco product samples were in the range of 95.1–102.8%. The proposed method has the merits of easy operation, fast analysis, high sensitivity and accuracy, which is applicable for batch determination and surveillance on caffeine, taurine and water-soluble vitamins in commercial tobacco products.

Stability of Neptunium(V) in Concentrated Acetic Acid Solutions

Np(V) acetate in glacial acetic acid and aqueous acetic acid solutions is resistant to disproportiona-tion and occurs in equilibrium with the NpO2(Ac)·H2O precipitate. Within the time of dehydration with excess acetic anhydride, Np(V) disproportionates. The inverse reproportionation process occurs after adding excess water to anhydrous acetic acid containing acetic anhydride, Np(IV), and Np(VI). Addition of HClO4 causes rapid disproportionation of Np(V) in anhydrous acetic acid and in concentrated acetic acid solutions. The spectra of suspensions containing Np(V) and potassium acetate in concentrated acetic acid contain absorption bands with maxima at 990 and 1020 nm, assigned to NpO2(Ac)32- anions and K2NpO2(Ac)3 particles, respectively.

Synthesis and application of PDMS/OP-POSS membrane for the pervaporative recovery of n-butyl acetate and ethyl acetate from aqueous media

Herein, octaphenyl-polyhedral oligomeric silsesquioxane (OP-POSS)/polydimethylsiloxane (PDMS) hybrid membranes were prepared for the recovery of n-butyl acetate and ethyl acetate via pervaporation. The affinity of PDMS/OP-POSS membranes for n-butyl acetate and ethyl acetate 1 solvents was determined by solubility parameters and equilibrium swelling experiments; the diffusion coefficients were determined by dynamic swelling experiments. The membranes were characterized using SEM, EDS, AFM, CA, FTIR, XRD and TGA to investigate the surface morphology, elemental distribution, roughness, hydrophobicity, intermolecular interactions, crystallinity and thermal stability, respectively. The effect of the OP-POSS content, feed concentration and temperature on membrane performance was investigated through pervaporation experiments. The swelling degree and penetrant mobility through the membranes significantly increased with increasing OP-POSS content. For dilute aqueous solutions containing n-butyl acetate or ethyl acetate, the total flux increased by increasing the OP-POSS content from 0 wt% to 10 wt%; the separation factor first increased followed by a decrease. The permeation flux and separation factor attained a maximum of 348 g∙m−2 h−1 and 221, respectively, at 6 wt% OP-POSS loading for a 0.5 wt% n-butyl acetate aqueous solution and 1694 g∙m−2 h−1 and 137, respectively, for a 4 wt% ethyl acetate aqueous solution, at 40 °C. The newly designed PDMS/OP-POSS membrane can be of significant assistance in separating n-butyl acetate, ethyl acetate and other similar compounds from aqueous mixtures on an industrial level.

Cobalt oxide nanoparticles anchored on discharged-graphene film for lithium-ion battery

In order to improve lithium storage capacity and cycle stability of the electrode materials, the combination of the active material and graphene is an effective way. Reduced graphene oxide (rGO) film on Ti substrate is obtained in an aqueous graphene oxide solution using a two-electrode constant voltage electrodeposition system. Then the rGO film on Ti substrate is used as working electrode to assemble lithium-ion batteries and discharged to 0.01 V. The discharged rGO film further reacts with cobalt ions in the cobalt acetate aqueous solution to fabricate the cobalt oxide (CoO)/rGO-precursor, and subsequently the CoO/rGO-700 composite is obtained by calcining the precursor at 700 °C under N2. Different measurements are conducted to evaluate the samples. The CoO/rGO-700 composites are further used as electrode material of lithium-ion batteries, which deliver an initial capacity of 1290.6 mAh·g−1 at 100 mA·g−1. For the first time, the synthetic method reported in this work can be extended to the synthesis of other metal or oxide/rGO composites.

Extraction of organic non-electrolytes with n-hexane from aqueous solutions of dipotassium phosphate and potassium acetate

At a temperature of 20 ± 1 °C, the distribution of model substances of various classes of organic non-electrolytes in n-hexane – aqueous solutions of dipotassium phosphate and potassium acetate was studied. The increments of the methylene and functional groups of organic non-electrolytes are calculated. It has been shown that in case of dipotassium phosphate, the nature of the salting out effect is enhancing the structure of the salt solution and the growth of the methylene group increment. For potassium acetate, the increment of the methylene group slightly increases with increasing salt concentration, and for most functional groups it increases significantly. An explanation of the dependences of the increment values on the nature and composition of the salt solution is given.

Quantitative determination of talatisamine and its pharmacokinetics and bioavailability in mouse plasma by UPLC-MS/MS

Talatisamine, as the efficacy ingredient of Aconitum, was known as a novel specific blocker for the delayed rectifier K+ channels in rat hippocampal neurons. In this study, a rapid, selective and reproducible UPLC-MS/MS separation method was established and fully validated for the quantitative determination of talatisamine levels in ICR (Institute of Cancer Research) mouse blood. A total of 24 healthy male ICR mice were divided into four groups that was administered talatisamine via intravenous at a dose of 1 mg/kg and oral administration of three doses (2, 4, 8 mg/kg). All blood samples were protein precipitate by using acetonitrile with an internal standard (IS) deltaline. The effective chromatographic separation was carried out through an UPLC BEH C18 analytical column (2.1 mm × 50 mm, 1.7 μm) with an initial mobile phase that consisted of acetonitrile and 10 mmol/L ammonium acetate aqueous solution (containing 0.1% formic acid) with a gradient elution pumped at a flow rate of 0.4 mL/min. Also, an electrospray ionization (ESI) was applied to quantify the talatisamine in the positive ions mode. The method validation demonstrated good linearity over the range of 1–1000 ng/mL (r2 ≥ 0.9993) for talatisamine in mouse blood with a lower limit of quantification (LLOQ) at 1 ng/mL. The accuracy values of the method were within 89.4% to 113.3%, and the matrix effects were between 103.2% and 106.3%. The mean extraction recoveries for talatisamine obtained from four concentrations of QC blood samples were exceeded 71.7%, and the relative standard deviation (RSD) both of intra- and inter-day precision values for replicate quality control samples did not exceed 15% respectively for all analytes during the assay validation. This method was successfully applied to the evaluation of the pharmacokinetic of talatisamine, regardless of intragastric or intravenous administration in mice. Based on the pharmacokinetics data, the bioavailability of talatisamine in mice was >65.0% after oral administration, exhibiting an excellent oral absorption.

The Thermal Expansion of AgxPb1 – xS Limited Semiconductor Solid Solutions

One-phase powders of AgxPb1 – xS cubic solid solutions with a maximum relative silver content to x = 0.12 were synthesized via the chemical codeposition from lead acetate and silver nitrate aqueous solutions in the presence of sulphidizer, as well as complexing and stabilizing agents. The thermal expansion of produced semiconductor solid solutions was first measured via the dilatometry in a temperature range of 295–580 K. As shown, substituting silver atoms for lead in AgxPb1 – xS results in a slight decrease in thermal expansion value, because of alterations in unharmonism of atomic vibrations.

Falling film flow of [EMIm]Ac ionic liquid aqueous solution on horizontal tubes considering the Marangoni effect

Experiments on falling film flow with a 60 wt% [EMIm]Ac (1-ethyl-3-methylimidazolium acetate) aqueous solution on cooled/heated horizontal tubes were conducted using an infrared thermal imaging camera to investigate the effect of Marangoni flow on the flow pattern and film width. The thermal stability of the [EMIm]Ac ionic liquid and the dependence of viscosity and surface tension on the temperature were presented. The physics of film flows with the Marangoni effect on horizontal tubes was analyzed. It is evidenced that the Marangoni effect exists on horizontal tubes and has significant influence on the falling film flow pattern and film width. When the film was heated, the film contracted and exhibited a sheet flow pattern, whereas a columnar pattern was observed under isothermal conditions. When the film was cooled, the film expanded and the columnar flow pattern was retained but with an increase in number of columns. Compared to the pure water, the average spreading film width with the 60 wt% [EMIm]Ac aqueous solution was narrower by approximately 20.1% and 9.8% at a liquid flow rate of 0.2473 kg m−1 s−1 as the film was cooled and heated, respectively.

Simultaneous quantitative analysis of phosphocreatine, creatine and creatinine in plasma of children by HPLC-MS/MS method: Application to a pharmacokinetic study in children with viral myocarditis.

A simple and rapid HPLC-MS/MS method was developed and validated for simultaneous measurement of phosphocreatine and its metabolites creatine and creatinine in children's plasma. A 50 μL aliquot of plasma was prepared by protein precipitation with acetonitrile-water (1000 μL, 1:1, v/v) followed by separation on a Hypersil Gold C18 column (35°C) with gradient mobile phase consisting of 2 mm ammonium acetate aqueous solution (pH 10) and methanol at a flow rate of 0.3 mL/min and analyzed by mass spectrometry in both positive (phosphocreatine) and negative (creatine and creatinine) ion multiple reaction monitoring mode. Good linearity (r> 0.99) was obtained for the three analytes. The intra-day and inter-day values of CV were <5.46% (-13.09% ≤ RE ≤ 2.57%). The average recoveries of the three analytes were 70.9-97.5%. No obvious impact was found for the quantitation of three analytes in normal, hemolyzed and hyperlipemic plasma. In the end, this method was successfully applied to a pharmacokinetic study of phosphocreatine in children (six cases) with viral myocarditis of children after intravenous infusion of 2 g of the test drug. The pharmacokinetc parameters of phosphocreatine/creatine were as follows: t1/2 0.24/0.83 h, Tmax 0.49/0.55 h, Cmax 47.34/59.29 μg/mL, AUClast 17.07/59.63 h μg/mL, AUCinf 17.16/79.01 h μg/mL and MRT 0.29/0.67 h.

The study of molecular interactions of aqueous solutions of Choline Acetate at different temperatures

Thermophysical properties viz. density ρ, speed of sound u, refractive index nD, and specific conductivity κ for aqueous solution of ionic liquid; 2-hydroxyethyl-trimethylammonium Acetate; [(C2H4OH)-(CH3)3N] [Acetate] (Choline Acetate) have been studied over the whole concentration range at different temperature (293.15 to 323.15) K at atmospheric pressure in order to understand the molecular interactions between solvent and solute. To have more insight of solute–solvent interactions occurring in aqueous solutions of Choline Acetate, apparent molar volume Vφ, apparent molar volume at infinite dilution Vφ0, limiting apparent molar expansibilities φE0, apparent molar compressibility KSφ, limiting isentropic compression KSφ0, molar refraction RM and limiting molar conductance ∧omhave been calculated over the whole composition range as a function of ionic liquid concentration. Thermophysical results confirm the presence of strong solute-solvent interactions in the aqueous solutions of Choline Acetate, which gets stronger with increase in temperature. Also, computational studies have been carried out for deeper understanding of interactions of aqueous solutions of Choline Acetate at molecular level by using Density Functional Theory (DFT). These results show that solute-solute interactions in Choline Acetate decreases on addition of water solvent hence are in good agreement with thermophysical results.

Synthesis of ZnS nanoparticles of required size by precipitation in aerosol microdroplets

ABSTRACTZinc sulphide (ZnS) nanoparticles were prepared by an aerosol method from zinc acetate and sodium sulphide (Na2S) aqueous solutions. Aqueous solution of zinc acetate was dispersed into the form of microdroplets, which were introduced by airflow to vigorously stirred aqueous solution of Na2S, which was in excess. Microdroplets served as microreactors, so the reaction took place only in limited volume. Particle size distribution was studied by transmission electron microscopy and by dynamic light scattering measurements. In this work, the equation that allows us to predict the final size distribution of ZnS nanoparticles using exact concentration of zinc acetate was derived and ZnS nanoparticles with predicted mean particle diameter around 50 and 70 nm were successfully synthetised.