高效液相色谱法快速测定蜂王浆中四环素类抗生素残留

本文建立了高效液相色谱法快速测定蜂王浆中3种四环素类抗生素（土霉素OTC、四环素TC、金霉素CTC）残留的检测方法。蜂王浆样品采用Na2EDTA-Mcllvaine缓冲液提取后以固相萃取（SPE）纯化、高效液相色谱-紫外检测器（HPLC-UVD）测定。3种四环素类抗生素在0~6.0 mg/L（金霉素0~12 mg/L）范围内,其浓度与峰面积呈良好的线性关系（r>0.999）;3个不同加标水平的方法回收率为83.0~101.2%。本方法简便、快速、准确、重现性好,可用于福建当地主要蜂王浆中四环素类抗生素残留的快速测定。     

超高效液相色谱-串联质谱法测定冻烤鳗中4种四环素类药物残留

建立了同时检测冻烤鳗中4种四环素类药物残留的超高效液相色谱-串联质谱法。样品采用4%高氯酸溶液提取,经HLB固相萃取柱净化,浓缩后以0.4%甲酸水溶液和甲醇作流动相进行梯度洗脱,电喷雾离子源,以正离子多反应监测模式(MRM)测定。4分钟内完成冻烤鳗中4种四环素类药物的残留检测。本方法在20~200μg/kg浓度范围内4种四环素类药物呈良好线性,其相关系数r0.9900,回收率均在72.4%~94.6%之间,相对标准偏差范围为4.6%~6.9%。土霉素、四环素、金霉素、多西环素的检测限(LOD)分别为1.55、1.48、5.91、3.11μg/kg;定量限(LOQ)分别为5.17、4.94、19.70、10.37μg/kg。本方法简便、快速、灵敏,适用于冻烤鳗中四环素类药物残留的检测。     

高效液相色谱荧光检测法同时测定水产品中4种四环素族药物残留的研究

建立了一种高效液相色谱荧光检测法同时测定水产品中4种四环素族抗生素残留的分析方法.水产品样品用柠檬酸缓冲液提取,清液用Oasis HLB固相萃取柱净化,1.36%的KH2P04溶液定容后,荧光检测器于λex=380 nm、λem=520 nm测定.土霉素、四环素在0.05～5.0mg/L范围内,金霉素、强力霉素在0.1～5.0mg/L范围内呈良好的线性关系,检出限分别为0.01、0.01、0.03、0.03mg/kg(S/N≥3),添加平均回收率80%～110%,相对标准差在2.0%～6.6%之间.具有方法简便、分离度高、检出限低的特点,满足常规检测及水产品安全控制的需要.     

荧光法测定茶叶铝含量及不确定度评定

铝在一定条件下对苯基荧光酮的自体荧光有显著的猝灭作用,由此建立了测定铝含量的方法。同时,对该体系进行了方法不确定度评定,计算出该方法扩展不确定度up为24μg·g-1,茶叶中铝含量为(277±24)μg·g-1。     

火焰原子吸收光谱法测定孕多维胶囊中钙、铁和锌的含量

用火焰原子吸收光谱法测定孕多维胶囊中钙,铁和锌的含量。结果表明,钙在8～16μg·mL~(-1)浓度范围,锌在0.5～3.5μg·ml~(-1)浓度范围,铁在3～11μg·mL~(-1)浓度范围内呈线性。钙,铁和锌的平均回收率分别为99.3％(RSD=0.93％),102.2％(RSD=0.57％)和100.6％(RSD=1.18％)。该方法快速、灵敏、准确,样品处理简便易行,可用于药品的质量控制。     

凝胶色谱净化-气相色谱串联质谱法测定海产品中得克隆残留量

建立了凝胶色谱(GPC)净化、气相色谱-串联质谱(GC-MS/MS)测定海产品中得克隆的方法。得克隆包括syn-DP和anti-DP两种异构体,样品中的得克隆经正己烷/丙酮(1:1,v/v)溶液提取、GPC净化后,GC-MS/MS采用多反应监测模式(MRM)采集数据后进行定性/定量分析。得克隆的加标回收率:syn-DP测定回收率为89.3%~102.5%;anti-DP测定回收率为85.4%~102.1%。syn-DP和anti-DP的检出限分别为0.2μg/kg和0.5μg/kg(S/N=3)。方法的相对标准偏差(RSD)均≤10.0%。采用本方法对采自温州的美国红鱼、中国毛虾,采自台州的鲈鱼,以及采自舟山的大黄鱼进行检测分析,结果上述样品均未检出。     

放心食品目录

正此次,放心食品目录将发布19种"放心食品"信息,品类涵盖生鲜食品、酒水饮料及休闲零食。鸡蛋放心365对目标市场的蛋产品进行抽检,本次共抽检消费者经常食用的鸡蛋3款产品,对抗生素(四环素、土霉素、金霉素)、三聚氰胺、农药残留8种(六六六4种、滴滴涕4种)、重金属(铅、无机砷、总汞、镉)、色素6种(苏丹红4种、柠檬黄、日落黄)、微生物(沙门氏菌),共22项指标进行检测。     

固相萃取-高效液相色谱-串联质谱测定水中5种大环内酯类抗生素

建立固相萃取(SPE)、高效液相色谱-串联质谱(HPLC-MS/MS)同时测定水中5种大环内酯类抗生素(罗红霉素、克拉霉素、阿奇霉素、螺旋霉素和泰乐菌素)的分析方法。水样中的抗生素通过Oasis HLB固相萃取小柱富集后,以C18反相色谱柱为分析柱,甲醇和0.1%甲酸水溶液为流动相,采用HPLC-MS/MS进行定量分析,检测方式为多反应监测模式(MRM),内标法定量。5种大环内酯类抗生素的回收率在64.8%~90.8%之间,仪器检出限为0.012~0.085μg/L,定量限为0.041~0.285μg/L。将建立的方法用于检测某化学工业园区周边地表水中5种目标分析物的残留,均未检测到泰乐菌素,其余4种抗生素均有不同程度检出,检出浓度在ng/L水平。     

等度高效液相色谱测定大豆异黄酮中大豆甙元和金雀异黄酮

本文介绍了等度高效液相色谱(HPLC)测定大豆异黄酮中二种主要成份:大豆甙元(Daidzein)和金雀异黄酮(Genistein)的方法。采用Atlantis C18色谱柱和EasyGuard C18,保护柱;以甲醇:0·1%醋酸(pH3·11)=51·5:48·5(v/v)为流动相;检测波长λ=254nm;流速1mL/min。在测定范围内(10-200ng)峰面积与质量浓度线性关系良好。大豆甙元和金雀异黄酮的相关系数分别为0·9984,0·9997·两组份回收率为97·0—102·92%·     

反相高效液相色谱法同时测定洁康舒洗剂中三组分的含量

建立反相高效液相色谱法同时测定洁康舒洗剂中大黄酸、大黄素和大黄酚含量的方法。采用反相高效液相色谱法。symmctry C18柱(3.9×150mm,5μm)流动相为甲醇—水—磷酸(80:20:0.1);流速为1.0mL·min-1;检测波长为432nm。大黄酸、大黄素和大黄酚的回归方程分别为:C1=7.3159×10-1+1.8966×10-5A,r=9994,C2=1.0513+1.5680×10-5A,r=0.9999C3=1.2260-1.4684×10-5A,r=0.9999三者分别在7.60~38.0μg·mL-1、1.75~8.75μg·mL-1、2.4~12.OOμg·mL-1范围内呈线性关系。平均回收率和RSD分别为98.02%、96.63%、97.05%和1.78%、1.20%、1.15%。该方法操作简便,测定结果准确可靠,可用于测定洁康舒洗剂中大黄酸、大黄素和大黄酚的含量。     

Enhanced photocatalytic degradation performance of organic contaminants by heterojunction photocatalyst BiVO4/TiO2/RGO and its compatibility on four different tetracycline antibiotics

Photocatalytic performance of four tetracycline antibiotics using BiVO₄/TiO₂/RGO composites was investigated. To make full use of catalysis, optimum preparation conditions involved RGO content, solution pH and hydrothermal temperature on the structure forming of BiVO₄/TiO₂/RGO composites were investigated. Subsequently, the obtained visible light-driven photocatalyst was used to degrade four kinds of tetracycline antibiotics involved tetracycline (TC), chlortetracycline (CTC), oxytetracycline (OTC) and doxycycline (DXC) for wastewater treatment. Results showed that BiVO₄/TiO₂/RGO photocatalyst exhibited excellent photocatalytic activity and high compatibility due to the enhanced separation efficiency of photo-generated carriers with high reduction and oxidation capability. The degradation process of four kinds of tetracycline antibiotics was traced and detected through identifying intermediates produced in the reaction system. And a possible catalytic mechanism for BiVO₄/TiO₂/RGO photocatalyst was put forward based on band gap structure of BiVO₄ and TiO₂.     

催化褪色光度法测定化学试剂中氯化物

建立了一种测定氯化钠含量的新的催化褪色光度法。在稀硫酸介质中,利用氯化钠对溴酸钾氧化甲基橙褪色反应的催化作用,使甲基橙在最大吸收波长510nm处的吸光度明显降低,且此吸光度的降低ΔA与氯化钠的浓度呈定量关系。氯化钠的含量在0～20μg·mL~(-1)范围内与ΔA呈线性关系,方法的检测限为1.46×10~(-7)μg·mL~(-1),用于化学试剂中氯化物杂质含量的测定,加标回收率为94.7%～95.9%。结果满意。     

Meso—四—(4—甲基,3—磺基苯基)卟啉分光光度法测定葡萄糖酸锌含量

本文研究了在抗坏血酸存在下TTPS_4与Zn(Ⅱ)的显色反应。结果表明:在PH为4.40的NaAc—HAc缓冲体系中,以抗坏血酸和吐温—60为辅助配位剂,在沸水浴中加热8分钟,Zn(Ⅱ)与TTPS_4即形成稳定的高灵敏度配合物,最大吸收波长位于430 nm,ε_(430)=5.5×10~5。Zn(Ⅱ)浓度在0～0.120μg/ml范围内遵守比耳定律。应用此法直接测定补锌口服液葡萄糖酸锌含量,结果满意。     

Fabrication of spherical Ti-6Al-4V powder by RF plasma spheroidization combined with mechanical alloying and spray granulation

Spherical Ti-6Al-4V powder was produced by RF plasma spheroidization combined with mechanical alloying and spray granulation. Particle size distribution, morphology, specific surface area, apparent density, flowability, element distribution and content of alloy powders after each stage during the process were investigated. Results show that the obtained spheroidized Ti-6Al-4V alloy powder has dense structure, good sphericity and high spheroidization ratio (98%), moderate particle size (37.8 μm) with narrow distribution. It also has excellent flowability (33.2 s· (50 g)^-1) and apparent density (2.53 g·cm^?3). In addition, elements distribution in the spherical Ti-6Al-4V alloy powder is uniform and most of elements content of it is within the standard of Ti-6Al-4V alloy.     

Skillfully grafted CO functional group to enhance the adsorption/photocatalytic mechanism of YMnO3/MgAl2O4 heterojunction photocatalysts

The YMnO₃ with different manganese salts includes MnSO₄·H₂O, MnCO₃ and C₄H₆MnO₄·4H₂O and YMnO₃/MgAl₂O₄ heterojunction photocatalysts (YMO/MAO) with different mass percentage of MgAl₂O₄ were synthesized by a simple wet chemistry method combined with low temperature sintering technology. The effects of manganese salts on the structure, functional groups, morphology, charge states and optical properties of YMnO₃ phase were studied in detail. The pure YMnO₃ with the uniformity of particles can be obtained when only C₄H₆MnO₄·4H₂O is used as manganese source. The results confirmed that the YMO/MAO heterojunction was constructed by one step low-temperature sintering technique. The YMnO₃/wt 10 % MgAl₂O₄ photocatalyst exhibits high optical absorption coefficient and highest adsorption capacity of 122.86 mg/g and degradation percentage of 98.98 % for the degradation of Congo red (CR), 86.16 % for the degradation of tetracycline hydrochloride (TC) and 72.51 % for the degradation of tetrabromo bisphenol A (TBBPA). The hydroxyl and superoxide radicals dominated the photocatalytic reaction process of YMO/MAO for the degradation of CR, TC and TBBPA. The present work pioneers the potential application of YMO/MAO grafted by CO functional group as dyes, antibiotics and persistent organic pollutants (POPS) adsorption / degradation catalyst and further provides technical reference for the synthesis of others heterojunction photocatalysts.     

APDC和MIBK萃取富集石墨炉原子吸收法测定天然水、废水中的硒

本文研究了天然水及废水中痕量硒的石墨炉原子吸收测定方法。天然水、废水等经硝酸—高氯酸进一步消化后,用APDC和MIBK萃取富集,用原子吸收石墨炉法测定。检出限0.7μg·L~(-1)。结果令人满意。     

Management of antibiotic residues from agricultural sources: use of composting to reduce chlortetracycline residues in beef manure from treated animals

Chlortetracycline (CTC) is one of only ten antibiotics licensed in the U.S.A. for use as growth promoters for livestock. The widespread use and persistence of CTC may contribute in development of antibiotic-resistant bacteria. The objective of this study was to determine the effect of composting on the fate of CTC residues found in manure from medicated animals. The effect of CTC residues on composting was also investigated. Five beef calves were medicated for 5 days with 22 mg/kg/day of CTC. Manure samples collected from calves prior to and after medication were mixed with straw and woodchips, and aliquots of the subsequent mixtures were treated in laboratory composters for 30 days. In addition, aliquots of the CTC-containing mixture were incubated at 25 degrees C or sterilized followed by incubation at 25 degrees C and 55 degrees C (composting temperature). The presence of CTC did not appear to affect the composting process. Concentrations of CTC/ECTC (the summed concentrations of CTC and its epimer ECTC) in the composted mixture (CM) and sterilized mixture incubated at 55 degrees C (SM55) decreased 99% and 98% (from 113 microg/g dry weight (DW) to 0.7 microg/g DW and 2.0 microg/g DW), respectively, in 30 days. In contrast, levels of CTC/ECTC in room temperature incubated (RTIM) and sterilized mixture incubated at 25 degrees C (SM25) decreased 49% and 40% (to 58 microg/g DW and 68 microg/g DW), respectively, after 30 days. Concentrations of the CTC metabolite, iso-chlortetracycline (ICTC), in CM and SM55 decreased more than 99% (from 12 microg/g DW to below quantitation limit of 0.3 microg/g DW) in 30 days. ICTC levels in RTIM and SM25 decreased 80% (to 4 microg/g DW) in 30 days. These results confirm and extend those from previous studies that show the increased loss of extractable CTC residues with increased time and incubation temperature. In addition, our results using sterile and non-sterile samples suggest that the decrease in concentrations of extractable CTC/ECTC at 25 degrees C and 55 degrees C (composting temperature) is due to abiotic processes.     

反相高效液相色谱法测定肾康口服液中黄柏的小檗碱含量

建立反相高效液相色谱法测定肾康口服液中黄柏的小檗碱含量。采用反相高效液相色谱法,Novapak C18柱(3.9×150mm,5μm)流动相为甲醇一乙腈(0.05mol·L-1)-磷酸二氢钠溶液(20∶3S∶45),流速为1.0mL·min-1,检测波长为346nm。小檗碱的回归方程为C=1.2616+1821X10-6A,r=0.9992,在4.00~20.00μg·mL-1范围内呈线性关系。平均回收率和RSD分别为101.32%和1.18%(n=5)。方法操作简便,测定结果准确可靠,可用于测定肾康口服液中黄柏的小檗碱含量。