离子色谱法测定水样中的氯化物

建立离子色谱法测定水样中氯化物的方法,Cl^-浓度在0．40～4．00mg／L范围内与色谱峰面积呈线性关系,线性方程为A=0．0680c＋0．0011,线性相关系数r=0．9995。样品6次测定结果的相对标准偏差为1．01％,加标回收率为91．8％～97．3％。与硝酸银滴定法进行比对试验,两种方法测定结果基本一致。离子色谱法操作方便快捷,污染少,测定结果准确、可靠。     

水蒸气蒸馏/离子色谱法测定磷矿石中氟化物和氯化物

建立了离子色谱法同时测定磷矿石中氟化物和氯化物的检测方法.利用国产的YSA-8型分离柱和DZS电自生型抑制器将日本岛津LC-10A液相色谱仪改造为抑制型离子色谱仪,用4.3 mmol/L Na2O3-6.0mmol/L NaHCO3混合溶液作淋洗液.试样用稀硫酸溶解,以水蒸气蒸馏法将磷矿石中氟化物和氯化物从样品中分离,用0.45μm微孔滤膜过滤后,进样分析.方法的相关性好（r＞0.999）,氟化物、氯化物测定的相对标准偏差分别为2.1%～2.6%、2.5%～3.8%,样品的加标回收率分别为93%～104%、95%～98%,与电位滴定法作对比测定的结果表明,方法的准确度较高.本方法线性范围宽、操作简便、快速,非常适合磷矿石中氟化物、氯化物的检测.     

微波消解-ICP—MS法同时测定砖茶中的铅、铜、铬和16种稀土元素

采用微波消解处理样品,以电感耦合等离子质谱（ICP-MS）法同时测定砖茶中的铅、铜、铬和16种稀土元素。采用外标法绘制校准曲线,分析了茶叶国家标准物质GBW 10016,测定值与标准值吻合。检出限为0．055-0．765μg／蚝,样品测定结果的相对标准偏差为0．2％～4．7％（n=6）。用加标回收的方法评价了该方法的准确性,回收率为88．0％-102．7％。该方法测定结果与电热板湿法消解前处理测定结果相比差异不显著。     

冷原子荧光法间接测定水中氰化物

本文详细研究了氰化物蒸馏条件及其稳定性问题，建立了一个冷原子荧光法间接测定水中氰化物的方法，并用于海水及氰化液中痕量ＣＮ－的测定，结果令人满意。ＣＮ－检出限为０．０２μｇ／ｍＬ，回收率９５％～９８％，变异系数７．３％～８．９％。     

石油馏分油中多元素的气相色谱-原子发射光谱联用模拟蒸馏研究

报道了在气相色谱-原子发射光谱联用仪上进行石油馏分油中C、H、S、N、C1多元素模拟蒸馏的研究结果。考察和讨论了进样方式,各元素的最小检测量和线性响应范围,H元素的非线性响应,分流失真等影响准确模拟蒸馏的因素,结果表明S元素在104的范围内是轻微弯曲的非线性,校正后的H元素定量误差不超过理论值的1％。提出的解决分流失真造成模拟蒸馏数据偏离正常值的方法,可使标准样品的测定值与标准值一致,波长为181．379um和174．200um的S和N元素实际样品模拟蒸馏准确定量的浓度下限分别为0．002％和0．04％。     

蒸馏分离-分光光度法测定枸杞子中的微量锗

利用盐酸与锗元素反应生成易挥发的四氯化锗，以蒸馏方法将四氯化锗分离出来，然后在1～1．5mol／L盐酸溶液中，用显色剂苯芴酮与四氯化锗进行显色反应生成橙红色配合物，在500nm波长处进行分光光度法测定。在0～200μg／(50mL)，线性方程为A=0．1714c．相关系数r=0．9996。该方法的检出限为0．0588μg／mL，测定结果的相对标；位偏差为2．24%～2．30%(n=11)，平均回收率为95．3％～95．4％。     

多波长线性回归紫外吸光光度法同时测定炼油厂污水苯？…

提出用多波长线性回归紫外吸光光度法同时测定炼油厂污水中的苯酚和苯胺。方法省去了萃取，蒸馏，显色等步骤，操作简单，对合成水样进行测定，相对标准偏差≤４．５７％，相对误差≤±２．３％。对炼油厂水样进行测定并进行加标回收试验，苯酚和苯胺的回收率分别为９９．４％－１０３．０％和９７．２％－１０４．）％，结果良好，苯酚和苯胺的最低检出限分别为０．０１０和０．０４８μｇ．ｍｌ＾－１。     

离子色谱法测定辛辣食品中的SO32-(SO2)含量

采用阴离子色谱-抑制电导检测器测定姜、蒜、辣椒、芥末、洋葱等带有辛辣气味的含硫食品中的亚硫酸盐(二氧化硫)残留量,采用酸性条件下的水蒸气蒸馏方法对样品进行提取纯化。线性范围为1．0～160．0mg／kg,回收率为80％～110％,满足出口食品检测要求。该方法适用于出口脱水菜和袋装水煮菜中SO3^2-(SO2)的测定。     

微蒸馏气相色谱法测定水中低级脂肪醇的研究

考察了微蒸馏气相色谱法测定水样中多种低级脂肪醇的可行性。利用微蒸馏技术将水中的醇分离富集,用程序升温气相色谱法测定。正丙醇、异丙醇、正丁醇、异丁醇、正戊醇、异戊醇的浓缩倍数分别为169．3,137．6,197．4,149．2,142．7,126．0。检出限分别为0．021,0．031,0．032,0．032,0．066,0．065mg／L。样品中所存在组分的平均回收率分别为甲醇82．60％,正丙醇93．25％,正丁醇94．88％;相对标准偏差分别为甲醇7．7％,正丙醇4．7％,正丁醇3．4％。方法适用于水中多种微量低级醇的同时分析。     

多位电动搅拌交换-全自动凯氏定氮法测定土壤中阳离子交换量

测定土壤阳离子交换量（CEC）的行业标准方法中,以玻璃棒手动搅拌进行离子交换和铵离子的清洗,使用传统方式进行蒸馏,手动滴定测定土壤样品中的阳离子交换量。但是这些方法搅拌操作劳动强度大、蒸馏过程较为繁琐,耗时长、效率低、不利于大批量样品的快速检测。以自制的多位电动搅拌装置代替玻璃棒搅拌,选择乙酸铵加入量、乙酸铵交换次数和交换搅拌时间3个因素,进行3因素3水平正交试验,结合实际操作需要选择加入50 mL乙酸铵溶液,交换1次,搅拌5 min,用乙醇清洗3次,运用全自动凯氏定氮仪进行蒸馏和测定土壤样品中的阳离子交换量。当搅拌时间为5 min时,搅拌速度大于100 r/min时,增加搅拌速度对分析结果无影响。使用本方法对不同酸碱性的国家标准物质和实际样品进行测定,测定结果的相对标准偏差为1.51%～2.38%,且国家标准物质的测定结果均在认定值的不确定范围内,表明本方法有较好的精密度和准确度。与标准方法相比,本方法以多位电动搅拌装置代替玻璃棒搅拌,用全自动凯氏定氮仪代替传统的蒸馏方式和手动滴定,自动化程度较高,蒸馏过程操作简单,解放了分析测试人员的双手,降低了劳动强度,自动滴定,节约了试剂成本,整个分析效率提高一倍以上,可实现批量化快速检测土壤中的阳离子交换量。     

Study of the behaviour of various phenolic compounds in the 4-aminoantipyrine and ultraviolet-ratio spectrophotometric methods without and with distillation

It is customary in industrial analysis in the determination of phenols by the 4-aminoantipyrine (4-AAP) and ultraviolet-ratio spectrophotometric methods to report the total of phenolic compounds as phenol. A study was therefore made of the behaviour of 36 representative phenolic compounds in the 4-AAP and UV-ratio methods, with and without distillation, to ascertain the apparent recoveries relative to that for phenol. The Fisher phenol analyser was used for the UV-ratio method, which depends upon the bathochromic shift (from about 270 to about 290 nm) usually obtained when the solution of the phenol is made alkaline. The apparent recoveries by the 4-AAP method both with and without distillation varied from 0 to 100%. The apparent recoveries by the UV-ratio method without distillation varied from 0 to 148%, and those with distillation varied from 0 to 110%. Sixteen of the compounds tested without distillation gave less than 10% recovery by the 4-AAP method and eleven gave less than 10% recovery by the UV-ratio method. The results after distillation indicated that several of the compounds did not distil completely.     

Possible remediation of dioxin-polluted soil by steam distillation

2,7-Dichlorodibenzo-p-dioxin (DCDD) was found to evaporate easily with water vapor from a heated solution. Steam distillation was also effective for the removal of DCDD from DCDD-applied soil; its concentration (250 microg/50g soil) in the original soil decreased to less than 5% after steam distillation for only 20 min. Actual dioxin-polluted soil in Tokorozawa City was partially decontaminated using the same method. These results suggest that steam distillation could be a new remedial method for soils contaminated with persistent environmental pollutants, such as dioxins and polychlorinated biphenyls.     

苯甲醇和苯甲酸制备实验的改进与创新设计

以苯甲醛为原料,通过Cannizarro反应制备苯甲醇和苯甲酸是有机化学实验教学中的经典内容。鉴于现有实验方案已难满足日益提升的教学要求,对其进行了改进与创新设计:采用微波辐射法合成,引入正交设计优化条件;采用紫外分光光度法定量测定粗产品中苯甲醇的含量;采用柱层析法分离得到苯甲醇。改进结果表明:KOH溶液浓度50%(质量百分比),微波功率500 W时,反应15 min完成。光度法定量显示苯甲醇产率可达82.0%。萃取分离后的粗产品用50:1和15:1石油醚/乙酸乙酯(体积比)梯度洗脱,柱层析分离后可得苯甲醇纯品,水相酸化重结晶后得到苯甲酸。产物的相关测试与表征结果与文献吻合良好。与传统方案相比,新方案时间锐减99%,产率提高约15%,萃取剂更安全,产率测定快速准确,产物纯化方法优化。将之用于教学,可通过各要点功能的分别承载,综合实现研究性思维与方法的培养目标。     

Three-dimensional porous photo-thermal fiber felt with salt-resistant property for high efficient solar distillation

The urgent need for fresh water resource is a public issue facing the world. Solar distillation for seawater desalination is a promising freshwater production method. Interfacial solar evaporation systems based on 2D photo-thermal membranes have been widely studied, but salt pollution is one of the main challenges for solar distillation. In order to solve this problem, a hydrophilic three-dimensional (3D) porous photo-thermal fiber felt (PFF) was obtained by one-step method, through a simple polydopamine (PDA) coating method with hydrophobic graphite felt as a substrate. The PFF had a good evaporation rate of 1.48 kg m^?2 h^-1 and its corresponding light-vapor conversion efficiency reached 87.4%. In addition, the PFF exhibited an excellent salt-resistant ability when applied to photo-thermal evaporation of high-salinity seawater with 10 wt% NaCl, owing to its intrinsic 3D macroporous structure for the migration circulation of salt ions. The development of the PFF offers a new route for the exploration of salt-resistant photo-thermal materials and is promising for the practical application of solar distillation.     

酸枣果肉中挥发性化学成分的提取及分析

报道了用蒸馏-萃取法和同时蒸馏-萃取法提取酸枣果肉中挥发性物质,测得两种方法提取的酸枣果肉挥发油含量分别为1．80％和2．30％。用GC／MS法从酸枣果肉挥发油中分别分离并确定出43种和28种化学成分,分别占酸枣果肉挥发油总检出量的95．62％和94．88％。用峰面积归一化法通过化学工作站数据处理系统,得出各化学成分在挥发油中的相对百分含量。     

超临界萃取中药白芷的化学成分的气相色谱质谱分析

采用超临界流体萃取法对传统中药白芷的化学成分进行了分离提取研究，利用气相-质谱联机技术，对其中的55种化学成分进行了鉴定，并测定了相对含量。与传统的水蒸气蒸馏法提取的白芷挥发油进行了比较，分析。实验结果表明，超临界CO2萃取法所得的产物，能保留药材白芷的所有有效成分，可以入药。     

Separation and determination of fluoride in plant samples

A simple and rapid separation method is described for the determination of fluoride in plant samples. Fluoride is separated by distillation in the presence of H(2)SO(4) and H(2)O(2) in a dry air steam. The variables that influence the distillation quantitation were optimized. The fluorides separated were subsequently determined by a spectrophotometric method of the La(III)-F(-)-alizarin complexone system. The precision of the procedure was significant, and the RSD was 3.7%. The accuracy of the method was statistically satisfactory, and the recovery was from 95.9 to 104.4%.     

Prediction of the physicochemical properties of gasoline by comprehensive two-dimensional gas chromatography and multivariate data processing

The estimation of physicochemical parameters such as distillation points and relative densities still plays an important role in the quality control of gasoline and similar fuels. Their measurements according to standard ASTM procedures demands specific equipments and are time and work consuming. An alternative method to predict distillation points and relativity density by multivariate analysis of comprehensive two-dimensional gas chromatography with flame ionization detection (GC×GC-FID) data is presented here. Gasoline samples, previously tested according to standard methods, were used to build regression models, which were evaluated by external validation. The models for distillation points were built using variable selection methods, while the model for relativity density was built using the whole chromatograms. The root mean square prediction differences (RMSPD) obtained were 0.85%, 0.48%, 1.07% and 1.71% for 10, 50 and 90% v/v of distillation and for the final point of distillation, respectively. For relative density, the RMSPD was 0.24%. These results suggest that GC×GC-FID combined with multivariate analysis can be used to predict these physicochemical properties of gasoline.     

Comparative studies of methylmercury determination in biological and environmental samples

Some parameters affecting the accuracy of various approaches to methylmercury (MeHg) determination in biological and environmental samples were studied. Different isolation techniques (ion-exchange, extraction, volatilization, distillation) and final measurement via cold vapour atomic absorption spectroscopy (CV AA) or gas chromatography (GC) were compared. Results obtained by the various isolation techniques are comparable for almost all biological and environmental samples, except for soils and some sediments, where disagreement between the results obtained by GC and CV AA was found. In order to resolve these problems, a new separation technique based on distillation of MeHg from the sample followed either by CV AA or GC was developed. The new method results in very good recovery and reproducibility (95 ± 2%) for all samples examined (fish, mussel, shrimp, blood, hair, algae, sediment, etc.), is specific for MeHg and provides for its differentiation from other species by an indirect CV AA determination. Gas-chromatographic measurement of the isolated MeHg using different packings and conditioning of the columns is also discussed. The distillation method with GC detection is advantageous in producing cleaner chromatograms and in prolonging the life-time of the packing and the intervals between reconditioning.     

拉曼光谱法测定芳烃物料的馏程

应用拉曼光谱法测定了芳烃物料的馏程.采用芳烃样品60个,其中50个为校正样品集,10个为预测样品集,在拉曼光谱位移为400 ～1 800 cm~(-1)范围内进行光谱预处理,并应用偏最小二乘回归法(PLS)建立了各馏程的校正模型,其相关系数(r~2)分别为0.87、 0.89、0.98、0.97、0.94、0.89、0.88(相应蒸馏回收百分数分别为5%、10%、30%、50%、70%、90%、95%).在置信水平99.5%,α为0.005时,各馏程t值均小于3.69(临界值),表明拉曼光谱法预测结果与常压蒸馏法的测定结果无显著性差别.采用拉曼光谱技术可以快速测定芳烃物料的馏程.