聚硫堇修饰的有机磷农药生物传感器的研制

研制了一种用于蔬菜中有机磷农药残留快速检测的电化学酶传感器。通过循环伏安法将电子媒介体硫堇电聚合在玻碳电极上作为电子传递体,用壳聚糖凝胶将乙酰胆碱酯酶固定于聚硫堇电极表面,制成了新型的有机磷农药生物传感器。结果表明在有机磷农药乐果浓度为0.1~60μg/mL范围内,酶电极抑制率(%)与乐果的浓度(C)的对数呈良好的线性关系,相关系数为0.9961,检出限以抑制率10%的农药浓度计算为0.05μg/mL。     

液相色谱-电喷雾质谱法测定白酒中5种有机磷农药残留

建立了固相萃取-高效液相色谱-电喷雾质谱(HPLC-S)测定白酒中乐果、敌敌畏、甲基对硫磷、马拉硫磷、对硫磷农药残留的检测方法.白酒样品用C18固相萃取柱富集净化、二氯甲烷洗脱、氮吹浓缩;采用C18反相色谱柱,以含有0.1%乙酸的水/甲醇(35∶65,v/v)为流动相;电喷雾正离子模式,选择有机磷农药的准分子离子为定性离子进行MS测定.结果表明,5种有机磷农药的平均加标回收率为71.0%～87.8%,相对标准偏差为2.7%～8.5%;方法的最小检出限为0.05～0.16靏/L.该法有很高的选择性、灵敏度和准确度,满足白酒中痕量有机磷农药的高灵敏分析.     

烟草水分检测仪的原理和使用

一、P&B—IC 型数字整盒卷烟水分检测仪1.原理简介本仪器原理框图如下图所示: 卷烟为一种高分子化合物介电物质,其介电系数ε受所含水分多少而变化。本仪器的针状传感器是电容式传感器,当卷烟放入电容式传感器后所呈现的电容变化值就由含水量决定(水分高,介电系数ε大,传感器电容变化大,反之则小)。高精度数字集成电路组成平衡对称复阻抗电桥,其功能是把针状传感器的电容变量转换成对应的电压变量。     

基于电沉积壳聚糖-碳酸钙-纳米金的有机磷农药生物传感器

目的 制备基于壳聚糖-碳酸钙-纳米金复合膜固定乙酰胆碱酯酶的新型电化学传感器。方法 一步电沉积壳聚糖、碳酸钙和纳米金修饰到玻碳电极, 由于电沉积过程有气泡产生, 使沉积到电极上的碳酸钙微粒形成了三维多孔的结构, 利于酶比较分散的固定在电极表面, 提高检测效率; 同时纳米金的引入不仅增大了电极比表面积, 而且促进电子的快速传递, 放大了检测信号。结果 将制备的生物传感器用来检测有机磷农药乐果, 检测限为2.5 pg/mL, 检测时间只需要7 min。结论 该生物传感器检测法实现了对有机磷农药快速、超灵敏的检测。     

聚硫堇修饰的一次性酶传感器检测 辛硫磷农药残留

目的研制一种用于蔬菜中有机磷农药残留快速检测的电化学酶传感器。方法通过循环伏安法将电子媒介体硫堇电聚合在丝网印刷电极上作为电子传递体,用壳聚糖凝胶将乙酰胆碱酯酶固定于聚硫堇电极表面,制成一种新型的有机磷农药生物传感器。结果在有机磷农药辛硫磷浓度为0.01~500μg/m L范围内,酶电极抑制率(%)与辛硫磷的浓度(c)的对数呈良好的线性关系,相关系数为0.9886,检出限以抑制率10%的农药浓度计算为0.006μg/m L。结论研制出成本低廉,使用方便,具有响应快、灵敏度高的有机磷农药生物传感器,可应用于果蔬中有机磷农药的快速检测。     

水硬度传感器的研制

以P.V.C为载体,磷酸酯类的钙盐为电活性物质研制而成水质硬度传感器,详细介绍了水硬度传感器的电极膜片及电极制作过程,并对所研制的传感器进行了灵敏度等性能测试。结果表明所研制的水质硬度传感器具有较高的灵敏度,是一种较为方便的水质硬度快速检测仪器设备。     

水质硬度传感器性能研究

水质硬度传感器是以P.V.C为载体，磷酸酯类的钙盐为电活性物质研制而成，对传感器性能进行测试，其响应时间≤5 s，检测范围广，实验证明它是一种较为方便的水质硬度快速检测仪器设备。     

生物传感器在有机磷农药残留量检测中的 应用研究进展

有机磷农药是我国使用最广泛的农药,具有广谱、高效等特点,但对人类的健康和环境安全存在潜在威胁。因此,发展快速、简易、准确测定有机磷农药残留量的方法具有重要意义。生物传感器具有简单、灵敏、低成本、便于携带,可实现现场监控等优点,已成为有机磷农药残留量速测技术中的研究热点。本文综述了近年来国内外生物传感器技术在有机磷农药测定中的应用情况,主要介绍了酶生物传感器、免疫生物传感器。最后本文对生物传感器在有机磷农药残留检测中应用的未来发展进行展望。     

电沉积法构建AChE/COD@AuNPs共固定化酶生物传感器差分脉冲伏安法快速检测有机磷农药

有机磷农药残留危害环境和人类健康。本文采用电沉积法将乙酰胆碱酯酶(AChE)与胆碱氧化酶(COD)固定化,共修饰于裸金电极表面,构建新型固定化酶生物传感器。通过电子显微镜对固定化酶形貌进行表征,结果表明：当固定化酶生物传感器上,乙酰胆碱酯酶与乙酰胆碱氧化酶的共修饰层数为2层,修饰圈数为35圈,在氯化乙酰胆碱浓度为2 mmol/L,pH 7.8的检测体系中,该生物传感器能够识别有机磷农药信号,且检测性能尚佳。传感器在有机磷农药质量浓度为10^-9～10-7mg/L时电流响应良好,工作曲线方程为y=0.0468x+1.2124(R²=0.9985),最低检出限1.15×10^-11 mg/L(S/N=3)。本研究为现场快速检测有机磷农药提供了新的研究方法。     

用于检测小分子靶标的电流型识体传感器研究进展

综述了电流型识体传感器在检测小分子靶标方面的研究进展:通过目标分子与电极上固定的核酸识体结合引起电流或电阻的变化和通过改变电活性物质与电极之间的距离2种方法均可检测目标靶分子.指出提高电流型识体传感器的灵敏度和适用性将是未来的发展方向.     

Microdetermination of phosphorus from infant formulas, casein and casein phosphopeptides

A spectrophotometric method, which has been proposed for the determination of phosphorus in biological fluids based on the formation of a phosphomolybdate complex, is adapted and validated for the determination of phosphorus in milk-based infant formulas, casein, casein phosphopeptides (CPPs) and the soluble fractions resulting from their gastrointestinal digestion, as well as in the fractions resulting from the ion-exchange high-performance liquid chromatography (IE-HPLC) of CE90CPP and in the soluble fraction of infant formula. The detection and quantification limits (1.1 and 3.6 mg P/100 g sample, respectively) are low enough for the purpose described. The linearity (from 0.1 to 8 g of phosphorus in the assay) is adequate. The precision of the method, expressed as relative standard deviation, is lower than 1%, and the accuracy checked by the analysis of SRM 1846: milk-based powdered infant formula is good. The quality of the method, together with the low cost and ease of use, makes it suitable for routine analysis.     

某河流入海段氨氮、总磷和总氮浓度变化特征及相关性分析

根据某河流入海段2020年10月至2021年10月氨氮、总磷和总氮的月度水质监测数据,分析了水体污染程度及变化特征,研究了各因子间相关性.结果表明,基于氨氮、总磷监测数据,入境断面水质类别为Ⅱ、Ⅲ类,首要污染因子中氨氮占比90％;出境断面水质类别为Ⅰ、Ⅱ类,首要污染因子中氨氮占比70％.氨氮与总氮比值变化趋势与水质指数...     

水热磷酸化改性大豆浓缩蛋白乳化性质的研究

采用水热磷酸化处理修饰大豆浓缩蛋白(Soybean Protein Concentrate,SPC),主要研究在SPC中添加不同浓度的三聚磷酸钠(SodiumTripolyphosphate,STTP)经水热处理改性后,SPC的磷酸化程度、乳化性质的变化。通过水热处理过程中向SPC添加0.1%~3%的STTP制备出不同磷酸化程度的磷酸化改性大豆浓缩蛋白(简称0.1%~3%P-HSPC);同时研究了改性前后SPC乳液乳析率、粒度分布的变化。结果表明:其中添加0.3%、0.5%、0.7%的STTP所得改性蛋白的磷酸化程度分别为0.226%、0.253%、0.28%,其磷酸化程度高于其他STTP浓度制得的改性磷酸化蛋白;并且改性后的SPC乳化性质有明显改善。     

Milk fever in dairy cows. VIII. Effect of injected vitamin D3 and calcium and phosphorus intake on incidence.

In a field trial, effects of prepartal intermuscular injection of 10 million units of vitamin D3 on incidence of milk fever were examined both in relation to intake of calcium and phosphorous during the dry period and previous history of milk fever. Based upon intake of calcium and phosphorus cooperating herds were grouped as feeding: 1) greater than .53% of the total ration dry matter as calcium and greater than .28% as phosphorus: 2) less than .47% as calcium and greater than .28% as phosphorus; 3) greater than .47% to less than .53% as calcium and greater than .22% to less than .28% as phosphorus. Injections of vitamin D3 given approximately 1 wk prepartum reduced incidence of milk fever in cows with previous history of milk fever in all three groups but had no effect in cows with no previous milk fever. Incidence of milk fever was lower in group 3 than for cows of groups 1 and 2 with previous milk fever and than for cows of group 1 with no previous history. The results indicate that careful control of calcium and phosphorus intake during the dry period at .5% calcium and .25% phosphorus of the dry matter of the total ration will limit milk fever incidence to about 10%. Injections of vitamin D3 as described will reduce inicidence of milk fever further in cows with previous milk fever but not in cows with no previous milk fever.     

Optimization of biological phosphorus removal from contaminated sediments with phosphate-solubilizing microorganisms

This study focused on the characteristics of phosphate-solubilizing microorganisms (PSMs) which can be applied for the removal of phosphorus from sediments to prevent eutrophication of lakes or ponds. A PSM isolated from rhizospheric soil and temporarily identified as Burkholderia glathei (MB 14) produced gluconate and acetate using glucose as a carbon source and its metabolic activity caused the pH of the liquid medium to decrease as low as 4.4. The molar ratio of solubilized PO4(3-)-P to total organic acids, gluconate and acetate, in the liquid medium was 1:2, which was lower than the theoretical molar ratio of 1:3 using Ca3(PO4)2 as a model phosphorus compound. In addition, biological PO4(3-)-P solubilization with MB 14 was more efficient than the direct addition of equivalent acid to the liquid medium. These results indirectly suggest that organic acids chelate Ca2+ during solubilization of PO4(3-)-P. The growth conditions for MB 14 that produced the maximum PO4(3-)-P solubilization were carbon sources of 8 g/l of glucose and 2 g/l of sucrose, and 0.1 g/l of arginine as a nitrogen source under an anoxic environment. The PSM species, MB 14, grown under these conditions was applied to treat contaminated dredged sediments in a bioslurry reactor. In 9 d, MB 14 solubilized 34.5% of total phosphorus in the contaminated dredged sediments.     

Organic phosphorus in some northern nigerian soils in relation to soil organic carbon and as influenced by parent rock and vegetation

The distribution of organic phosphorus in relation to soil organic matter and the influence of parent material and vegetation of organic P level was studied in a number of soil profiles in the northern half of Nigeria. There was a close relationship between soil organic carbon and organic phosphorus contents of these soils. The ratios of these two ingredients were all less than 200:1. This fact suggests that organic P is likely to be mineralised. The effect of parent rock on organic P contents was slight, but there was an indication that soil profiles on metamorphic parent rocks contained more organic phosphorus than those on sedimentary parent material. Vegetation had a great influence on organic P as shown by the relatively higher organic phosphorus contents of profiles from southern Guinea savanna and the lower contents of the Sudan vegetation zone. The profiles from impeded drainage sites (fadamas) were generally richer in organic phosphorus than were those from comparable vegetation zones on well drained sites.     

不同供磷能力的土壤施磷对烤烟根体积、根冠比以及根系伤流组分的影响

以烤烟为供试作物,研究了不同磷水平对烤烟的根体积、根冠比以及伤流强度,伤流液中可溶性糖、磷、钾、钙、锌、镁含量的影响。结果表明,随施磷量的增加,低磷土壤,根体积、伤流强度增大,根冠比呈下降趋势,伤流液中可溶性糖含量先增加,后又稍有下降;中磷土壤,根体积变化趋势是先升高后又降低,根冠比下降,伤流强度增大,可溶性糖含量先增加后又快速下降。低磷土壤施磷能促进烟株对矿质营养的吸收,中磷土壤则表现各异。相关分析表明,低磷土壤烟株伤流液中P和Zn,K和Mg存在显著正相关;中磷土壤伤流液中Mg和伤流强度,Ca和Mg、P、伤流强度存在显著正相关,Zn和伤流强度,Zn和Mg存在显著性负相关。      

硝酸盐在除磷脱氮中的作用

除磷过程中，厌氧段硝基氮浓度越高、聚磷菌厌氧释磷所受的影响越大；摄磷段存在硝基氮，聚磷菌可以利用其作为替代的电子受体，在不曝气的情况下吸磷。但是，由于以硝基氮为电子受体时聚磷菌对有机物（PHA）利用率较低，所以吸磷的速率和数量均不如氧为电子受体的系统，除磷效率亦较低。研究了厌氧氨氧化反应的几种可能的电子受体，发现硝酸盐、亚硝酸盐、硫酸盐可用作该生物反应的几种电子受体，而醋酸盐是该反应的抑制剂。其中，当亚硝酸盐作为电子受体时，厌氧氨氧化菌混培物转化氨的速率最快。     

Rapid detection of pork meat freshness by using L-cysteine-modified gold electrode

In this research, a simple and rapid glucose sensor was developed and applied in the detection of meat glucose. The gold electrode was modified using L-cysteine and nanogold solution, and a polyglutamate–glucose oxidase (GOx) complex was prepared and dropped on the modified electrode; the electrostatic binding between the L-cysteine on the electrode surface and the polyglutamate moiety of the complex resulted in the formation of a GOx-attached electrode. Glucose in meat was detected, and the enzyme electrode showed a quick response. The optimum operating conditions for this sensor were determined as follows: 0.1 M citrate buffer pH 5.0 was found to be suitable for this experiment, and the temperature was kept between 25 and 30 °C which is the suitable range for the GOx activity. A linear relationship was found between 0.1 and 0.9 mM/mL. High pressure liquid chromatography (HPLC) was also used to detect pork meat glucose, and total volatile basic nitrogen (TVBN) production was as well detected as a quality index of pork meat freshness. The results showed that the developed sensor was fast and reliable method for the detection of glucose in meat.     

不同品牌CN琼脂上铜绿假单胞菌色素表达的研究

目的 对铜绿假单胞菌在不同品牌CN琼脂上的色素表达及其原因进行研究。方法 比较ATCC 10145、ATCC 15442、CMCC 10104 3种铜绿假单胞菌标准菌株在5种不同品牌CN琼脂上的色素表达, 并测定CN琼脂的磷含量。结果 5种CN琼脂的磷含量在123~1560 mg/kg之间, 最高的磷含量与最低磷含量相差10余倍。只产青脓素的铜绿假单胞菌ATCC 15442在各CN琼脂上均为黄色菌落, 在紫外线下产荧光。只产绿脓菌素的铜绿假单胞菌ATCC 10145, 在含磷量低的CN琼脂上呈现为蓝色菌落, 表现为产绿脓菌素; 而随着磷含量的增加, CN琼脂上绿脓菌素的表达逐渐减弱。既产绿脓菌素又产青脓素的铜绿假单胞菌CMCC 10104在含磷量低的CN琼脂上呈现为蓝色菌落, 表现为产绿脓菌素; 而随着磷含量的增加, CN琼脂上绿脓菌素的表达逐渐减弱, 青脓素的表达逐渐增强, 菌落颜色逐渐变黄并在紫外线下产荧光。结论 铜绿假单胞菌在5种不同品牌的CN琼脂上的表达色素的情况与CN琼脂的磷含量有关, CN琼脂含磷量越低, 越有利于绿脓菌素的表达, 青脓素的表达受到抑制; CN琼脂含磷量越高, 越有利于青脓素的表达, 绿脓菌素的表达受到抑制。