二混蜜中钾的离子交换柱层析法分离和回收

在制糖工业中钾是一种影响糖分回收的造蜜剂.提出以离子交换柱层析分离和回收二混蜜中钾盐的新思路,研究了钾在离子交换层析柱上的分离和洗脱工艺条件.结果表明,实验条件下BK001树脂在层析柱中吸附K+的最佳的工艺条件为:操作流速2 BV/h、锤度50°Bx、温度60℃、高径比为8:1;各工艺条件对钾的分离影响大小顺序是:高径...     

Optimized Analysis of Organic Acids in Edible Mushrooms from Portugal by Ultra Fast Liquid Chromatography and Photodiode Array Detection

Organic acid profiles of different mushroom species were obtained by ultra fast liquid chromatography, by means of photodiode array detector. The chromatographic separation was achieved using a SphereClone (Phenomenex) reverse phase C₁₈ column using an isocratic elution with sulphuric acid (3.6 mM) at a flow rate of 0.8 mL/min. All the compounds were separated in 8 min. The method was optimized using Agaricus bisporus sample and proved to be reproducible and accurate. Organic acid profiles were quite homogeneous for all mushroom samples; oxalic, malic and fumaric acids were the main organic acids; some samples also presented quinic and citric acids. Sarcondon imbricatus was the species that presented the highest total content (254.09 mg/g dry weight (dw)), while Bovista nigrescens presented the lowest concentration (1.33 mg/g dw). The high amounts of organic acids present in all the species may suggest that they could be related to the antioxidant activity found in these species and previously reported by us.     

连续离子交换法分离L- 乳酸的工艺设计及优化

与传统固定床离子交换工艺相比,连续离子交换分离L-乳酸具有连续、稳定、高效等显著优点。本实验基于静态吸附和固定床离子交换实验结果,设计优化连续离子交换工艺,实现了L-乳酸经济、连续、高效分离。通过静态吸附实验,筛选出最优树脂为732树脂,可在1min内达到吸附平衡,吸附量达345.97mg/g;最佳解吸剂为0.5moL/L H2SO4溶液。通过固定床离子交换实验,确定最佳进料流速40mL/min、最佳高径比7.5:1、穿透时间21.5min,用0.5mol/L H2SO4溶液进行解吸,解吸率超过97%。通过连续离子交换实验,确定了交换区(1#～6#)、交换后水洗区(18#～20#)、再生区(12#～17#)、再生后水洗区(9#～11#)和产品顶水区(7#～8#)的最佳进料流速分别为40、40、140、35mL/min和20mL/min,且各出口浓度呈周期性稳定变化。     

Lead and cadmium in foods/drinking water from Slovenian market/taps: Estimation of overall chronic dietary exposure and health risks

ABSTRACT

Approximately 3000 food samples from the Slovenian market and 2500 drinking (tap) water samples in the period 2011 ? 2016 were evaluated for the presence of toxic elements lead (Pb) and cadmium (Cd) and the overall chronic dietary exposure was assessed for each element. The highest mean concentrations were found for Pb in products for special nutritional use – dietary supplements (0.383 mg/kg) and for Cd in fish and seafood (0.117 mg/kg). The consumption data were obtained from the national study of the household budget and from the European Food Safety Authority (EFSA) summary statistics. Chronic dietary exposure was estimated deterministically. The average Pb and Cd intakes from food and drinking (tap) water ranged for children from 0.90 to 1.021 µg/kg bw/day and 4.65 to 5.65 µg/kg bw/week, respectively, and for adults, including adolescents, from 0.40 to 0.53 µg/kg bw/day and 1.98 to 2.82 µg/kg bw/week, respectively. The high consumption of cereal-based foods and vegetables contributed most to overall Pb and Cd intake in the majority of the age groups. The exposure to Pb was generally lower and that to Cd was higher compared to the average EU values. The most exposed were children, as the health-based guidance values were exceeded for both elements, which indicates a health concern. An important contribution to Cd exposure can be attributed to grains and potatoes grown in Slovenia, where the soil contains more Cd than that in other EU countries. Further efforts to reduce Pb and Cd intake are required to minimize potential health risks.     

Application of Electrohydrodynamic Technology for Folic Acid Encapsulation

Folates are a group of vitamins vital for the growth and development of the central nervous system. Most of these natural derivatives of folic acid are prone to oxidation and are very sensitive towards heat, temperature, oxygen, and light. Encapsulation of folic acid within inert matrices of a polymer can improve its stability and stop its degradation by light and oxygen. Electrohydrodynamic (EHD) technology is capable of generating fine droplets ranging from micrometers to nanometers in diameter from the breakup of a jet depending on the flow rate and applied electrical potential difference. The aims of this study were to generate nano-sized particles of folic acid encapsulated in sodium alginate (Na alginate) using EHD technology and to study the effect of voltage and flow rate on particle size as well as the structure of the prepared particles. It was established that 40 mg/ml (Na alginate) concentration can be used in single jet EHD technology. However, only 10 mg/ml concentration furnished stable jetting at any applied voltage and flow rate. So, this concentration was utilized and used to encapsulate higher dosages of folic acid. It was observed that the optimum flow rate for obtaining spherical particles of uniform diameter (4.2?±?1.2 μm) was 10 μl/min at a voltage of 12 kV. Upon drying, these particles acquired a diameter in the range of 50–200 nm and became less spherical in shape. As the folic acid concentration is increased from 1 to 10 mg/ml, the percentage yield of particles at a constant Na alginate concentration increased by over 10 % and the corresponding encapsulation efficiency doubled. FTIR spectroscopic studies revealed the presence of folic acid within Na alginate matrices and also no characteristic chemical interaction between them. It can be concluded from the above research findings that, at 10 mg/ml Na alginate concentration, 10 μl/min flow rate, and 12 kV voltage, a high amount of folic acid (5 mg/ml) can be encapsulated within Na alginate matrices, with high percentage yield (70 %) and loading capacity (96 %), generating non-spherical dried beads/particles of 90–150 nm in diameter.     

SD3 离子交换树脂分离提取ATP 的研究

通过对SD3 离子交换树脂对ATP 动态吸附、洗杂和洗脱条件的考察,确定最适吸附条件为：样品溶液H 2.0,浓度8.25g/L,离子交换柱的高径比为10(装柱湿树脂80g),流速1.0ml/min;最优洗杂液为pH1.5 HC1＋ 0.05mol/L NaCl 的溶液;ATP 的最优洗脱液为pH12.0 NaOH+0.1mol/L NaCl 溶液,优洗脱速度为0.5ml/min。     

Selection of the Solvent and Extraction Conditions for Maximum Recovery of Antioxidant Phenolic Compounds from Coffee Silverskin

The extraction of antioxidant phenolic compounds from coffee silverskin (CS) was studied. Firstly, the effect of different solvents (methanol, ethanol, acetone, and distilled water) on the production of antioxidant extracts was evaluated. All the extracts showed antioxidant activity (FRAP and DPPH assays), but those obtained with methanol and ethanol had significantly higher (p?<?0.05) DPPH inhibition than the remaining ones. Due to the lower toxicity, ethanol was selected as extraction solvent, and further experiments were performed in order to define the solvent concentration, solvent/solid ratio, and time to maximize the extraction results. The best condition to produce an extract with high content of phenolic compounds (13 mg gallic acid equivalents/g CS) and antioxidant activity [DPPH?=?18.24 μmol Trolox equivalents/g CS and FRAP?=?0.83 mmol Fe(II)/g CS] was achieved when using 60 % ethanol in a ratio of 35 ml/g CS, during 30 min at 60–65 °C.     

一株椰糠纤维降解菌的分离、鉴定及特性研究

以椰糠作为碳源,从红树林土壤中分离了一株高产纤维素酶的真菌,命名为DZ10。经形态、生理生化和分子生物学试验,鉴定菌株DZ10为长枝木霉菌（Trichoderma longibrachiatum）。该菌在pH值为6.5、培养温度为35 ℃、初始NaCl含量为2.0%、添加K+终浓度为0.1 mmol/L条件下,椰糠降解率最高为39.88%;在pH值为6.5、培养温度40 ℃、初始NaCl含量3.0%、添加K+终浓度为0.1 mmol/L条件下,羧甲基纤维素酶活力（CMCA）最高值为80.07 U/mL;在pH值为6.0、培养温度35 ℃、初始NaCl含量1.5%、添加K+终浓度为0.1 mmol/L条件下,滤纸酶活力（FPA）最高值为73.81 U/mL。Ca2+、K+对菌株DZ10产酶和椰糠降解率有促进作用,Mg2+抑制菌株DZ10产酶和椰糠降解率。     

Sequential Injection Chromatography as Alternative Procedure for the Determination of Some Food Preservatives

Sequential injection chromatography for the determination of benzoic acid (BA), sorbic acid (SOA), and salicylic acid (SA) has been investigated. Separation was performed on a monolithic C-18, (5?×?4.6 mm) column which is normally used as a guard column, with 1% acetonitrile: ammonium acetate buffer pH 4.5 as a mobile phase at a flow rate of 1.20 mL/min at ambient temperature and with the UV detection at 235 nm. Under the conditions, separation of the three compounds was achieved within less than 3 min. Linear calibrations were found to be 1–100 mg/L for the three: BA, SOA, and SA with detection limits of 1.9, 0.7, and 0.3 mg/L. The developed procedure was demonstrated to be an effective alternative fast and simple method for the analysis of food, fruit juice, syrup, and soft drink samples.     

Simultaneous determination of aspartame,acesulfame-K,saccharin, citric acid and sodium benzoate in various food products using HPLC–CAD–UV/DAD

A newly developed method for simultaneous determination of aspartame, acesulfame-K, saccharin, citric acid and sodium benzoate in various diet supplements and non-alcoholic beverages in a single run is presented. The analytes were analysed by high-performance liquid chromatography coupled to a charged aerosol (Corona CAD) and ultraviolet–diode array detectors simultaneously connected in series. Mass spectrometer MicrOTOF-QII from Bruker Daltonik (Bremen, Germany) was used to obtain the mass spectra for peak identifications. The method was validated using a Thermo Hypersil Gold-C18 column packed with 5 μm shell particles (150 × 4.6 mm) and methanol–water with 0.05 % TFA gradient mobile phase at a flow rate of 0.80 mL/min. The elaborated method was validated for linearity, precision and accuracy. The analytical results obtained in the validation study were highly satisfying; the recoveries for the analytes studied ranged between 98.1 and 101 % and the precision values from 0.11 to 1.73 %. By these procedures, the three sweeteners (aspartame, acesulfame-K and saccharin), citric acid and sodium benzoate could be well separated and quantitatively determined in varied food products. Hundred millilitres of soft drinks contained on average 5.50 mg of aspartame, 6.38 mg of saccharin, 8.94 mg of acesulfame-K, 9.05 mg of sodium benzoate and 111 mg of citric acid. Citric acid was the most abundant additive in all the samples analysed except for table sweeteners, and its highest concentration was determined in diet supplements, i.e. 347 mg/g. The percentage of adequate daily intake realisation in case of all additives is lower than 10 %, except for sodium benzoate in isotonic drinks (10.1 %).     

Synthesis of octadecyl acrylate-co-ethylene glycol dimethacrylate resin for removal of dark-colored compound from apple juice and comparison with polyvinylpolypirrolidone (PVPP)

Adsorption process has an importance for improving the color of juice and also stabilizing the final product during the shelf life. In this study, polyvinylpolypirrolidone (PVPP) and octadecyl acrylate-co-ethylene glycol dimethacrylate (ODA-EGDMA) polymeric resins were used as adsorbents for improving the color properties of apple juice. The ODA-EGDMA resin was prepared by classical suspension polymerization technique and characterized by electron microscopy. The obtained spherical particles diameters were between 20 and 140 μm. PVPP was selected as reference polymeric material for its importance in the juice industry. The adsorption kinetics of dark-colored compounds on adsorbent polymeric resins were studied at different adsorbent resins concentrations (1, 2, 4, and 8 g adsorbent resin per liter of apple juice) at the constant temperature (20 °C) in batch reactor. Langmuir adsorption model was applied for both PVPP and ODA-EGDMA polymeric adsorbents. The Langmuir isotherms were plotted for both polymeric adsorbents by evaluation of the absorbance data of apple juice at 420 nm. Langmuir isotherm's empirical constants known as K _ad and Q ₀ were calculated from the equilibrium data. Numerical value of K _ad and Q ₀ were determined as 5.0578 and 0.3089 for the ODA-EGDMA polymeric resin, 2.4824 and 0.5268 for the PVPP adsorbent, respectively. The scope of this study included comparison of reusability and regeneration properties of the each polymeric adsorbent. For this purpose, series of experiment were done in pack bed column application. Pressure drop measured throughout the PVPP pack bed column was 4.8 times higher than ODA-EGDMA pack bed column at same flow rate (2.5 mL/min) during the this group experiment. ODA-EGDMA resin and PVPP were regenerated with NaOH (4% w/v, 50 °C) after each run. After regeneration, average removal of dark color (relative absorbance change at 420 nm) of apple juice was determined as 76.47±0.90% for ODA-EGDMA and 91.51±0.86% for PVPP adsorbent resin.     

Lead,cadmium and organochlorine pesticide residues in hunted red deer and wild boar from northern Italy

The objectives of the present study were to assess heavy metal cadmium (Cd), lead (Pb) and organochlorine pesticide concentrations in tissues of red deer (Cervus elaphus) and wild boar (Sus scrofa) from nine hunting areas and to evaluate related risk factors for the host animal. Over a period of 2 years, a total of 1055 and 210 masseters, 424 and 201 livers, 642 and 152 kidneys were collected from wild boar and red deer, respectively, and concentrations of Cd, Pb and organochlorine pesticides were determined. Comparing the two species, Cd concentration in the kidney (3.72 mg/kg), liver (0.67 mg/kg) and muscle (0.02 mg/kg) of wild boar was found to be significantly higher than in the organs of red deer (1.02 mg/kg in the kidneys, 0.07 mg/kg in the liver and 0.006 mg/kg in muscle). Mean Pb concentrations were found to be similar in both animals, with 0.39, 0.52 and 2.60 mg/kg detected in the wild boar kidney, liver and muscle, respectively, and 0.24, 0.21 and 2.04 mg/kg in the respective organs of the red deer. No difference in concentrations were found based on age class, location of tissue sample or contaminant in the case of wild boar. By contrast, a significantly lower Cd concentration was found in the kidney of the young red deer. The search for organochlorine pesticides in both red deer and wild boar produced negative results with values below the limits of detection. Due to the high levels of renal Cd and muscle Pb detected in wild boar and red deer, further research needs to be carried out in an effort to identify the source of contamination and preserve the health of animals and humans.     

Simultaneous Determination of Flumequine and Oxolinic Acid Residues in Aquatic Products Using Pressurized Capillary Electrochromatography

A rapid method for detection of flumequine (FQ) and oxolinic acid (OA) residues from fish tissues was established using pressurized capillary electrochromatography (pCEC). Residual FQ and OA were extracted from fish tissue samples with acidified acetonitrile and purified on an Oasis HLB C₁₈ solid-phase extraction column. The extract was then analyzed by pCEC with the mobile phase (pH?=?3) consisting of acetonitrile and 15 mM ammonium acetate (45: 55, v/v, respectively) at the flow rate of 0.07 mL/min, detection wavelength of 324 nm, and applied voltage of ?10 kV. Baseline separation of FQ and OA was achieved in 10 min; both drugs showed good linearity in the range of 0.2–5 μg/mL. The recoveries of FQ and OA were between 82 and 92 % (relative standard deviation?=?3.63–5.96). The limits of detection for FQ and OA were 0.1 and 0.08 mg/kg, respectively.     

Preparation of Acryloyl <Emphasis Type="Italic">β</Emphasis>-Cyclodextrin Organic Polymer Monolithic Column and Its Application in Solid-Phase Microextraction and HPLC Analysis for Carbofuran and Carbaryl in Rice

An acryloyl β-cyclodextrin (A-β-CD) monolithic column for solid-phase microextraction (SPME) and determination of carbofuran and carbaryl by high-performance liquid chromatography (HPLC) have been prepared through a “one-step” polymerization method. The synthesis conditions, including the volume of cross-linker, the ratio and volume of mixed porogenic solvent consisted of methanol and N,N-dimethylformamide were optimized. The prepared monolithic column was characterized by thermogravimeteric analysis (TGA), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and Brunner-Emmet-Teller (BET) measurement. The eluent type, volume and flow rate, sample volume, flow rate, acidity, and ionic strength were optimized in detail. Under the optimized conditions, a simple, rapid, and sensitive SPME-HPLC method was developed for determination of carbofuran and carbaryl in rice samples. The method yielded a linear calibration curve in the concentration ranges of 1.5–200 μg/kg for carbofuran and 0.3–200 μg/kg for carbaryl with correlation coefficients (R ²) of above 0.9955. Limits of detection (S/N = 3) were 0.5 μg/kg for carbofuran and 0.1 μg/kg for carbaryl, respectively. The recoveries of this method ranged from 88.1 to 105.8%. The relative standard deviations were less than 8.1%.     

啤酒酵母在处理含镉工业废水中的应用研究

研究了啤酒酵母对废水中镉离子的生物吸附过程，分析了啤酒酵母吸附镉离子的速度、pH、温度等的影响。实验表明，啤酒酵母对镉离子的吸附时间短（15min）；pH值范围宽（4～8）；酵母的单位吸附量大（46．5mg／g）。对于高浓度的含镉废水，酵母具有较强的吸附能力；废水经二次吸附处理后均能达到排放标准。用啤酒废酵母作为重金属离子的吸附剂，可提高啤酒企业的附加值和科技含量，也可降低啤酒企业排放废水时对环境的污染。（孙悟）     

Continuous production of wine vinegar in bubble column reactors of up to 60-litre capacity

This paper describes the development of a continuous acetic acid fermentation process for the production of wine vinegar in bubble column reactors of up to 60 l capacity. To determine appropriate fermentation conditions a study of the influence of residual ethanol concentration, inlet flow rate and aeration was carried out using a 6-l laboratory reactor, white table wine as fermentation medium, a temperature of 30 °C and an air flow rate of 0.125 min^-1 (vvm). The concentration of acetic acid obtained in the continuous wine vinegar production ranged from 91 g/l at 28.6 ml/h to 28 g/l at 154.1 ml/h by increasing the inlet flow rate. As expected, the biomass decreased as well, from 208 mg/l to 106 mg/l. The maximum acetification rate was observed in the range 85-110 ml/h, corresponding to a value of about 1.1 g/l/h. A further increase in the flow rate produced a slight decrease in the acetification rate. Best yields, between 94.5 and 94.7%, were obtained in the flow rate range of 60-75 ml/h. The acetification rate was improved only by about 10% by increasing the aeration from 0.125 to 0.250 min^-1. The continuous wine vinegar production was scaled up from the laboratory fermentor to a 60-l pilot acetator. During the steady state (residential time >6), with an inlet flow rate of 950 ml/h, temperature of 30 °C and aeration of 0.250 min^-1, the following parameters were obtained: acetic acid concentration 72 g/l, overall productivity 1.41 g/l/h and yield 94.2%.     

鲁氏酵母脱除水溶液中Cd~(2+)的研究

研究了鲁氏酵母(Zygosaccharomyces rouxii)CICC1379作为吸附剂对水溶液中镉的脱除作用。结果表明:温度和振荡频率对Cd2+脱除率影响不大,初始pH和菌体浓度则影响很大。初始pH3-5,脱除率均随pH增大而增大。pH5-7是鲁氏酵母对低、高2组溶液的脱除Cd2+的最适pH。Cd2+脱除率随时间变化的曲线表明,酵母在10.22mg/L和53.39mg/LCd2+溶液中,在5min内完成大部分吸附并在30min内达到吸附平衡。     

大叶藻总黄酮的大孔树脂纯化工艺

为纯化大叶藻中提取的总黄酮,选择5 种大孔吸附树脂,通过静态吸附和解吸实验,选定两种最优树脂D101-1和AB-8;再将两种树脂进行混合实验,选出混合吸附树脂最优混合比例,最后确定最佳纯化工艺条件：D101-1和AB-8吸附树脂按2∶3比例混合、上样液pH 3、样液质量浓度1.25 mg/mL、洗脱液乙醇体积分数70%,上样量和上样流速分别为6 BV和3 BV/h,洗脱体积和洗脱流速分别为5 BV和3 BV/h条件下进行纯化实验,样液中的总黄酮含量由原来（12.66±0.42）%上升至（51.25±1.26）%。     

HPLC Determination of Spectinomycin in Feed Premixes and Dosage Forms Using 1-Naphthyl Isocyanate Precolumn Derivatization with UV Detection

A new, simple, and sensitive HPLC method was developed for the determination of spectinomycin hydrochloride in dosage forms and feed premixes through derivatization with 1-naphthyl isocyanate. The separation was achieved on a C₁₈ column using a mobile phase consisting of acetonitrile/water (50:50 v/v, pH 3.2) in a flow rate of 1 mL/min with UV detection at 230 nm. The factors influencing the derivatization reaction yields were carefully studied and optimized. The method was linear over the concentration range of 10–100 μg/mL with a limit of detection 0.25 μg/mL and limit of quantitation 1.75 μg/mL. The developed method was successfully applied to the analysis the drug in the commercial dosage forms and spiked feed premix samples; the average recoveries were 99.79 and 99.56, respectively. The analytical performance of the method was fully validated and the results were satisfactory. A proposal of the reaction pathway was presented.     

Determination of heavy metal ions in vegetable samples using a magnetic metal–organic framework nanocomposite sorbent

This paper describes the synthesis and application of a novel magnetic metal–organic framework (MOF) [(Fe₃O₄-benzoyl isothiocyanate)/Cu₃(benzene-1,3,5-tricarboxylate)₂] to pre-concentrate trace amounts of Cd(II), Pb(II), Zn(II) and Cr(III) ions and their determination by flame atomic absorption spectrometry. A Box–Behnken design was used to find the parameters affecting the pre-concentration procedure through response surface methodology. Three factors including uptake time, amount of the magnetic sorbent and pH of the sample were selected as affecting factors in the sorption step, and four factors including type, volume and concentration of the eluent as well as the elution time were selected in the elution step for the optimisation study. The opted values were 30 mg, 10.1 min, 5.9, EDTA, 4.0 ml, 0.57 mol l^–1 EDTA solution and 13.0 min for the amount of the magnetic sorbent, uptake time, pH of the sample, type, volume, concentration of the eluent, and elution time, respectively. The limits of detection (LODs) were 0.12, 0.7, 0.16, and 0.4 ng ml^?1 for Cd(II), Pb(II), Zn(II) and Cr(III) ions, respectively. The relative standard deviations (RSDs) of the method were less than 7.2% for five separate batch experiments for the determination of 30 μg l^?1 of Cd(II), Pb(II), Zn(II) and Cr(III) ions. The sorption capacity of the [(Fe₃O₄-benzoyl isothiocyanate)/MOF] was 175 mg g^?1 for Cd(II), 168 mg g^?1 for Pb(II), 210 mg g^?1 for Zn(II) and 196 mg g^?1 for Cr(III). It was found that the magnetic MOF nanocomposite demonstrated a higher capacity compared with Fe₃O₄-benzoyl isothiocyanate. Finally, the magnetic MOF nanocomposite was successfully applied to the rapid extraction of trace amounts of the heavy metal ions from vegetable samples.