Reagent optimization for on-line simultaneous polarographic determination of trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in the presence of anextremely large excess of Zn^(2+)

Reagents are optimized for the simultaneous determination of trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in zinc sulfate solution, which contains an extremely large excess of Zn^(2+). First, the reagents and their doses for the experiment are selected according to the characteristics of the zinc sulfate solution. Then, the reagent doses are optimized by analyzing the influence of reagent dose on the polarographic parameters(i.e. half-wave potential E_(1/2) and limiting diffusion current I_p). Finally, the optimization results are verified by simultaneously determining trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in the presence of an extremely large excess of Zn^(2+). The determination results indicate that the optimized reagents exhibit wide linearity, low detection limits, high accuracy and good precision for the simultaneous determination of trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in the presence of an extremely large excess of Zn^(2+).

Flow-Injection Microcolumn on-Line Preconcentration for theDetermination of Chromium(Ⅵ)

A rapid and sensitive on-line preconcentration method for spectrophotometric determination of chromium (VI) in nature water is described. Preconcentration and determination are based on (i) the quantitative and fast adsorption of chromium (VI) on the high surface area nanometer-size TiO2 (anatase) powders, which prepared by a sol-gel method from hydrolysis of TiCI4 and (ii) the quantitative and reproducible elution of Cr (VI) by 2. 0 mol. L-1 HCI. A mini-column system for preconcentration is developed, Cr(VI)on the mini-column is eluted and merged with a stream water and DPCB (1, 5-diphenylcarbazide ) as the chromogenic reagent. The Proposed system permits throughputs of 6 sample h--l (0. 001 μg mL-1 Cr(VI) ) or 20 sample h-1 (0. 1 μg mL-1Cr (VI) . The preconcentration factor is 55. The detection limit is 0. 8 ng·mL-1 Cr(VI). The reproducibility is satisfactory with a relative standard deviation of less than 3. 35% (0. Of μg'mL-1Cr (VI), n = 5).

ON-LINE ELECTROLYTIC DISSOLUTION OF SOLID METAL SAMPLE AND DETERMINATION OF COPPER IN ALLOY BY AAS

On-line dissolution of solid metal sample can be carried out by electrolysis under the control of flow injection analyzer(FIA),and the dissolved sample can be transferred to atomic spectrometer for the direct analysis.The hyphenated technique of FIA on-line electrolytic dissolution of alloy and atomic absorption spectrometer(AAS)detection is developed.The research is focused on the effects of electrolyte composition and electrolysis parameters on the sample dissolving,as well as the quantitative analysis of Cu in Al alloy samples.

DETERMINATION OF ANTIMONY IN WATER SAMPLES BY FLOW-INJECTION HYDRIDE GENERATION ATOMIC ABSORPTION SPECTROMETRY WITH ON-LINE ION-EXCHANGE COLUMN PRECONCENTRATION

On-line ion-exchange separation and preconcentration were combined with flow-injection hydride generation atomic absorption spectrometry (HGAAS) to determine ultra-trace amounts of antimony in water samples. Antimony(Ⅲ) was preconcentrated on a micro-column packed with CPG-8Q chelating ion-exchanger using time-based sample loading and eluted by 4 mol l^(-1) HCl directly into the hydride generation AAS system. A detection limit (3σ) of 0.0015μg l^(-1) Sb(Ⅲ) was obtained on the basis of a 20 fold enrichment and with a sampling frequency of 60h^(-1). The precision was 1.0% r.s.d.(n=11) at the 0.5μg l^(-1) Sb(Ⅲ) level. Recoveries for the analysis of antimony in tap water, snow water and sea water samples were in the range 97-102%.

Determination of vanadium in food and traditional Chinese medicine by graphite furnace atomic absorption spectroscopy

Various experimental conditions were described for the vanadium determinationby graphite furnace atomic absorption spectroscopy (GFAAS). The experiments showed that whenatomization took place under the conditions where the combination of a pyrolytic coating graphitetube and fast raising temperature were used and the temperature was stable, the signal peak shapescould be improved, the sensitivity was enhanced, and the memory effect was removed. The vanadium infood and traditional Chinese medicinal herbs can be accurately determined using the standard curvemethod.

A Highly Sensitive and Selective Spectrofluorimetric Method for the Determination of Arsenic at Pico-Trace Levels in Some Groundwater, Real, Environmental, Biological, Food and Soil Samples Using 2-(<i>α</i>-Pyridyl)-Thioquinaldinamide

A very simple, ultra-sensitive, highly selective and non-extractive new spectrofluorimetric method for the determination of arsenic at pico-trace levels using 2-(α-pyridyl)-thioquinaldinamide (PTQA) has been developed. PTQA has been proposed as a new analytical reagent for the direct non-extractive spectrofluorimetric determination of Arsenic (V). This novel fluorimetric reagent, PTQA becomes oxidized in a slightly acidic (0.025 - 0.1 M H2SO4) solution with Arsenic (V) in absolute ethanol to produce highly fluorescent oxidized product (λex = 303 nm;λem = 365 nm). Constant and maximum fluorescence intensities were observed over a wide range of acidity (0.025 - 0.1 M H2SO4) for the period between 2 min and 24 h. Linear calibration graphs were obtained for 0.001 - 800-μgL-1 of As, having a detection limit of 0.1-ngL-1;the quantification limit of the reaction system was found to be 1-ngL-1 and the RSD was 0% - 2%. A large excess of over 60 cations, anions and complexion agents (like, chloride, phosphate, azide, tartrate, oxalate, SCN, etc.) do not interfere in the determination. The developed method was successfully used in the determination of arsenic in several Certified Reference Materials (alloys, steels, ores, human urine, hair, nails, bovine liver and sediments) as well as in some biological fluids (human blood, urine, hair, nail and milk), soil samples, food samples (vegetables, fruits, rice, corn and wheat), solutions containing both arsenic (III) and arsenic (V) speciation and complex synthetic mixtures. The results of the proposed method for assessing biological, food and soil samples were comparable with both ICP-OES & AHG-AAS and were found to be in excellent agreement.

SIMULTANEOUS DETERMINATION OF VITAMIN B COMPLEX (THIAMINE, RIBOFLAVIN, NIACIN, PYRIDOXINE AND FOLIC ACID) IN FOODS BY HPLC

A high performance liquid chromatographic assay has been developed for the simultaneous determination of five water soluble vitamins:thimine, riboflavin, niacin, pyridoxine and folic acid in cereal products and fresh vegetables. Food samples were hydrolyzed in 0.4 mol/L HCl, autoclaved at 120℃ 15 psi for 20 minutes, using a μ-Bondapak column (3.9×300mm, Waters Co.), a mobile phase of methanol-water (30:70) (0.005 mol/L heptanesulfonic acid) and a flow rate of 1.0 ml/min gave the most satisfactory separation of the five water soluble vitamins. A double channel deteetion was used: four vitamins (B_5, folic acid, B_2, B_1) were detected hy UV spectrophotometry (254 nm) first, pyridoxine (B_6) was detected by fluoromelry (EX 290nm, EM 395 nm) afterwards. Detection limits were 2, 5, 5, 2and 5ng, linear ranges were 5-10ng, 5-50ng, 5-40ng, 5-50ng and 10-50ng for B_1, B_2, B_5, B_6 and folic acid respectively. Recoveries were 92-100%(B_5), 51-52% (folio acid), 103—105% (B_2), 99—100% (B_6) and 91.3—102% (B_1) respectively. In comparison with a reference method and checking with food composition tables, very satisfactory results were obtained by this method.

A Highly Sensitive and Selective Spectrofluorimetric Method for the Determination of Vanadium at Pico-Trace Levels in Some Real, Environmental, Biological, Soil and Food Samples Using 2-(<i>α</i>-Pyridyl)-Thioquinaldinamide

A new spectrofluorimetric reagent 2-(α-pyridyl)-thioquinaldinamide (PTQA) has been synthesized and characterized through novel reaction techniques. A very simple, ultra-sensitive and highly selective non-extractive new spectrofluorimetric method for the determination of vanadium at Pico-trace levels using 2-(α-pyridyl)-thioquinaldinamide (PTQA) has been developed. PTQA has been proposed as a new analytical reagent for the direct non-extractive spectrofluorimetric determination of vanadium (V). This novel fluorimetric reagent, PTQA becomes oxidized in a slightly acidic (0.0035 - 0.0085 M H2SO4) solution within vanadium (V) in 20% ethanol to produce highly fluorescent oxidized product (λex = 319 nm;λem = 371 nm). Constant and maximum fluorescence intensities were observed over a wide range of acidity (0.0035 - 0.0085 M H2SO4) for the period between 5 min and 24 h. Linear calibration graphs were obtained for 0.001 - 600-μg·L-1 of V, having a detection limit of 0.3-ng·L-1;the quantification limit of the reaction system was found to be 3-ng·L-1 and the RSD was 0% - 2%. A large excess of over 60 cations, anions and complexing agents (like, chloride, phosphate, azide, tartrate, oxalate, SCN- etc.) do not interfere in the determination. The developed method was successfully used in the determination of vanadium in several Certified Reference Materials (alloys, steels, serum, bovine liver, drinking water, soil and sediments) as well as in some environmental waters (potable and polluted), biological fluids (human blood, urine, hair and milk), soil samples and food samples (vegetables, rice and wheat) solutions containing both vanadium (IV) and vanadium (V) speciation and complex synthetic mixtures. The results of the proposed method for assessing biological, food and vegetable samples were comparable with inductively coupled plasma optical emission spectroscopy (ICP-OES) and atomic-absorption spectrophotometer (AAS) was found to be in excellent agreement.

Sturgeon (Acipenser gueldenstaedtii) Acclimatization to Optimal Growth Conditions—A Case Study of Adaptation, Nutrition, Reproduction, and Sex Determination

The development of new agricultural industries is an important challenge for a region’s economic establishment. The connection between a research department at MIGAL Institute and biotechnology in aquaculture is an example (case study) of the interrelationships that also exist in other departments. This article describes the research conducted by the institute supporting the development of the aquaculture industry in Israel through the introduction of a relatively new fish species—the Russian sturgeon (Acipenser gueldenstaedtii), with the relevant information to be used for acclimatization to aquaculture conditions in northern Israel. Many aspects related to bringing a new species to Israel and working with this new industry to study its adaptation to existing conditions in the north of the country influenced the economic success of this new type of precision agriculture. This article describes the research on various aspects affecting the successful acclimatization of Russian sturgeon in northern Israel: introduction, food development, reproduction, hormone systems that control reproduction and growth, gonadal development, and molecular markers for sex determination, differentiation, and economic assessment of caviar production.

Assessment of Household Food Security and Its Determinants in Minjar Shenkora and Ada’a woredas of Central Ethiopia

Food security issues become one of the critical concerns and top priority areas for Ethiopia.This study analyzed rural households’food security status and its determinants in Minjar Shenkora woreda of Amhara Regional State and Ada’a woreda of Oromia Regional State.Data were collected from 240 randomly selected rural farm households.The study employed both descriptive statistics and a binary logistic regression model to estimate the status and determinants of households’food security,respectively.The findings indicated that the average dietary energy available for food secured households was 2,860.6 kilo calorie per day while 1,891.7 kilo calorie per day for the insecure group.According to the findings of the binary logit model,factors such as education level,farm size,livestock ownership,cooperatives membership,off-farm income and credit access have positive and significant effects on household food security.While household size has a negative and significant effect on household food security.The results recommend that interventions should target at improving rural financial services and off-farm activities that increase households’income and focusing on those most significant variables when attempting to enhance household food security.

Evaluation of the determinants of food security within the COVID-19 pandemic circumstances-a particular case of Shaanxi,China

Background:Agricultural food production and distribution industries may play a vital role in determining the current conditions of any country’s food security and sustainable development goals.This paper examined the determinants of food security within three distinct aspects(effective utilization of food,food availability,and food access)within the COVID-19 epidemic situation.Methods:The qualitative set-up of the study comprised with the identification of drivers by critical analysis of published papers and discussion held with some practitioners.The quantitative data used in this research were collected from a survey covering the agricultural food supply industry in China(Shaanxi Province).The survey was conducted from November to December 2020 and we mainly focus on three aspects of food security(effective utilization of food,food availability,and food access).The core analytical assumptions were made by employing exploratory factor analysis(EFA),confirmatory factor analysis(CFA),and structural equation modeling(SEM).Results:After analyzing the data collected from 257 agricultural food productions and distribution personnel along with the hypothesis testing,it found that the determinants of the effective utilization of food were positively related to the determinants of food access(β=0.291,p=0.029)and food availability(β=0.298,p=0.011),and the determinants of food availability were positively related to the food access determinants(β=0.128,p=0.002).The association and variance values between food availability and food access were 0.659 and 0.407;the association and variance values between for effective utilization of food and food availability aspects were 0.465 and 0.298,and between effective utilization of food and economy were 0.508 and 0.475.Conclusion:The study critically evaluated the interconnection among the crucial determinants within the banner of three dimensions,which will act as a major contribution to existing literature.This research will help the government and industry to develop policies and strategies for the successful implementation of all the associated determinants of food security in terms of the epidemic situation.

Structured Equation Model of Tuberculosis Incidence Based on Its Social Determinants and Risk Factors in Bandar Lampung, Indonesia

World Health Organization through tuberculosis (TB) control averted up to six million deaths and cured thirty-six million people in 1995-2008, but had less success in reducing TB incidence, especially in thirteen high burden countries, including Indonesia. Therefore, TB control will need to have more emphasis on the issues of social determinants, as social determinants affect TB’s incidence directly and/-or through TB’s risk factors. This study aimed to identify a significant effect of social determinants and the risk factors of TB incidence. The research setting was at twenty-seven primary health centers and one hospital that have implemented the Directly Observed Treatment Short Course (DOTS) strategy in Bandar Lampung municipality, Indonesia. Respondents of this research were 238 smear-positive TB patients as case group and 238 patients without TB as control group. Research variables consisted of “social determinants”, “housing condition”, “household food security” and “health access” which were set as latent variables and measured through their indicators. Data had been collected by using questionnaire and then was analyzed with Structural Equation Modeling using SmartPLS 2.0 software. The result showed that “social determinants” through “housing condition” and “household food security” affected “TB incidence”. Moreover, “social determinants”, “housing condition” and “household food security” can be used to explain 34.1% variation of “TB incidence”. In conclusion, the knowledge can be used to support the TB control program, particularly to implement the DOTS strategy together with improving social determinants, housing condition and household food security.

Detection of illegal dyes in foods using a polyethersulfone/multi-walled carbon nanotubes composite membrane as a cleanup method

In this paper, a polyethersulfone （PES）/multi-walled carbon nanotubes （MWCNTs） composite membrane was prepared us- ing phase inversion. The surface morphology and internal structure of the membrane were observed by scanning electron microscopy （SEM）. The effects of MWCNTs content on various aspects of membrane performance such as porosity, water flux, and antifouling characteristics were investigated. Results showed that proper addition of MWCNTs would improve the properties of the membrane. MWCNTs had a strong adsorption capacity for industrial dyes and the composite membrane could be used as an effective method to identify and clean up illegal dyes in foods. In addition, this new method for iden- tifying dyes is rapid： the cleanup procedure in the determination of illegal dyes in foods by the composite membrane was shortened to 30 min or less compared to 6-8 h for traditional methods.

Nutritional Status of Mothers and Its Determinants in Alemtidad Area, Khartoum

Background: Nutritional status of mothers is considered one of the major problems facing mothers in the world. The nutrition plays a major role in mothers and child health. Objective: This study aims to assess mothers’ nutritional status and its determinants in Alemtidad area, Khartoum. Methods: A descriptive community based survey was conducted in the Alemtidad area of Khartoum between November 2012 and December 2012. One hundred and eighty mothers were selected by simple randomization. Data were collected by using structured designed questionnaire which was then analyzed by (SPSS) program version 20. Results: The study conducted among mothers in Alemtidad area;their age ranged between 19 and 86 years with the mean age 38 ± 12 years. From those mothers about half were unemployed, and having mainly primary and secondary educational level. 81.1% of mothers were not able to select the proper food according to age and nutrients and about 71.1% of mothers took two meals per day and 23.3% one meals per day, and only 5.6 take three meals per day. The Body Mass Index (BMI) was calculated to measure the nutrition status of mothers;this study shows that mothers in Alemtidad are mainly overweight and obese, 45.6% and 18% respectively and only 35% within normal range of Body Mass Index (BMI). Conclusion: The study concludes that mothers are either overweight or obese (45.6%, 17.7% respectively). Compared to national and international statistics the findings of this study reflect high Body Mass Index (BMI) of mothers in Alemtidad.

Assessment of Household Food Security in the Face of Climate Change and Variability in the Upper Blue-Nile of Ethiopia

It is widely recognized that climate variability and frequent droughts resulting from E1-Nino phenomenon are among the major risk factors affecting agricultural production that might contribute to hunger and food insecurity in East Africa in general and Ethiopia in particular. The objectives of the present study were to examine the food security status and determinants of household food security among 442 randomly selected households in the Muger sub-basin of the Blue-Nile basin using household survey, focus group discussion （FGD） and key informant interview data collection methods. Both descriptive statistics （mean, chi-square test and t-test） and binary logit econometric model were used to analyze the data. The results showed that 57.8% of the households are food secure, while the remaining 42.2% of the households are food insecure. The binary logit regression results revealed that adoption of soil conservation, small-scale irrigation and employing different agronomic practices are important factors influencing household food security. Moreover, land holding and livestock ownership positively and significantly affected household＇s food security. The results further showed that family size and distance to the nearest market are important factors affecting food security in the inverse direction. The results highlighted careful investments on sustainable land management practices and small-scale irrigation that reduced sensitivity and increased the adaptive capacity of small_holder farmers to the adverse effect of climate change and variability. This study further highlighted the significance of livestock ownership and landholding in attaining food security under changing climate. The irmdings call for action based on advocacy family planning to curb population growth and invest in creating functional value-chain that help farmers＇ viable market for their produces.

药食同源植物杀虫剂制备及其防治效果

以常见药食同源植物辣椒和花椒的果实、大蒜鳞茎和洋葱鳞叶为试验材料,与有效微生物群(Effective microorganisms,EM)菌液混合发酵制作杀虫剂,使用液相色谱分析其杀虫成分含量;结合室内和田间试验,筛选高效生物杀虫剂并评估其杀虫效果。结果表明,花椒125g,辣椒25g,大蒜125g,洋葱250g混合发酵30d,稀释30倍液得到最佳杀虫活性物A;施药后第6天对桃蚜防治效果最佳,虫口减退率为92.38%。田间试验结果表明,杀虫剂A在施药后第5天对桃蚜防治效果最佳,校正防效为78.05%;与市售植物源杀虫剂比较,杀虫剂A持效时间较长,在施药后第6天虫口减退率为70.29%,校正防效为82.95%,杀虫效果显著高于0.3%印楝素乳油和1.3%苦参碱水剂。研究得到一种高效植物源杀虫剂A,为药食同源植物制备杀虫剂研发及其在生产中推广应用提供试验依据和有效方法。

食品中富马酸二甲酯测定方法研究现状

富马酸二甲酯因其防霉、保鲜效果好,在食品中被广泛应用。然而,富马酸二甲酯食用过多,会导致健康损害,已被列入我国第二批食品中可能违法添加的非食用物质名单。因富马酸二甲酯价格便宜,仍屡次被使用,并引发一系列食品安全问题,随着人们对食品安全和健康的关注不断增加,富马酸二甲酯引起了公众的关注,检测食品中富马酸二甲酯含量变得至关重要。本文主要对食品中富马酸二甲酯的提取方法和仪器检测方法研究现状进行阐述,为建立快速测定食品中富马酸二甲酯方法提供理论参考。

发酵食品中生物胺前处理和检测方法的研究进展

生物胺(BA)广泛存在于发酵食品中,过量摄入生物胺会危害人体健康。本文主要综述了近年来新型的几种前处理技术:分散液液微萃取、中空纤维液相微萃取、基质固相分散萃取、分子印记法、QuEChERS法、电膜萃取、超声波辅助提取法以及发酵食品中生物胺的主要检测方法的研究进展,包括超高效液相色谱-质谱法、高效液相色谱法、薄层色谱法。

保健食品中灵芝三萜含量测定的方法研究

目的:为解决灵芝孢子粉类产品中灵芝三萜含量测定中室间和室内对比误差较大的问题,研究了以《NY/T 3676—2020灵芝中总三萜含量的测定分光光度法》为代表的紫外分光光度法测定过程中提取试剂、温度、显色剂用量、提取溶液测试体积及样品称样量等因素对实验结果的影响。方法:灵芝孢子粉的乙酸乙酯溶液超声60 min并过滤后,量取适量毫升滤液蒸干后,加入0.40 mL 5%香草醛-冰乙酸与1.00 mL高氯酸于60℃水浴中加热15 min,取出,冰水浴冷却后加入5.00 mL冰乙酸,15 min后以1 cm比色皿于548 nm波长测定吸光度。结果:确定了以紫外分光光度法测定灵芝三萜含量时最佳提取溶剂为乙酸乙酯,显色反应时最佳水浴温度为60℃,5%香草醛-冰乙酸溶液与高氯酸最适用量分别为0.40 mL和1.00 mL,最适宜的提取液适用量为0.5 mL。要保持含量测定的稳定性,其称样量是整个实验的关键,且与样品本身含量有关。结论:该方法可广泛应用于各类灵芝孢子粉中灵芝三萜含量的测定。

分散液液微萃取技术在液态食品分析中的应用

分散液液微萃取技术(Dispersive Liquid-Liquid Microextraction,DLLME)是一种新型的样品前处理方法,它具有有机试剂用量少、操作简便快速等优点,广泛应用于食品样品中痕量目标物的提取。本文阐述DLLME的类型,DLLME技术在液态食品分析中的应用,以期能为后续研究者在DLLME领域的进一步开发与创新提供思路。