液液萃取–气相色谱法测定地表水中硝基氯苯

建立气相色谱法同时测定地表水中3种硝基氯苯同分异构体的方法。用液液萃取法萃取地表水样品中的硝基氯苯,并对影响萃取效率的因素进行了优化。采用甲苯作为萃取溶剂,以DB–1701毛细管色谱柱(30 m×0.32mm,0.25μm)进行分离,气相色谱法检测地表水中硝基氯苯的含量。硝基氯苯的质量浓度在0.00~40.0μg/L范围内与其色谱峰面积呈良好的线性关系,线性相关系数均大于0.995,检出限为0.07~0.08μg/L,低于《地表水环境质量标准》限值。加标回收率为85.3%~98.0%,测定结果的相对标准偏差均小于2%(n=6)。该方法操作简单,重现性好,准确度好,检测速度快,适用于地表水中硝基氯苯的测定。     

GC－MS/MS法测定食品接触用硅橡胶制品中6种环硅氧烷迁移量

基于气相色谱－串联质谱（GC－MS/MS）建立了食品接触用硅橡胶制品中6种环硅氧烷（D4 ~ D9）向50%乙醇、95%乙醇、异辛烷迁移量的检测方法,并应用于38批次实际样品的检测。取10 mL迁移实验得到的50%乙醇浸泡液,使用2 mL正己烷萃取,经过滤后测定,95%乙醇和异辛烷浸泡液直接经过滤后测定。采用HP－5 MS色谱柱分离,多反应监测模式进行分析。结果表明,D4 ~ D9在0.05 ~ 1.00 mg/L或0.20 ~ 5.00 mg/L范围内具有良好的线性关系,相关系数（r2）不低于0.996 0。各目标物的检出限为0.02 ~ 0.07 mg/L,定量下限为0.05 ~ 0.20 mg/L,回收率为90.1% ~ 106%,相对标准偏差不大于13%。使用该方法对市面上的食品接触用硅橡胶制品进行迁移实验,发现D4~D9向50%乙醇存在迁移风险;向95%乙醇和异辛烷迁移的检出率为80%,迁移风险最大。D4 ~ D9在95%乙醇和异辛烷第3次的迁移检出率显著大于第1次,而在50%乙醇中第1次迁移和第3次迁移的检出率无明显差异。     

高效液相色谱法同时快速测定饮料中的12种食品添加剂

建立了高效液相色谱法同时测定12种食品添加剂(苯甲酸、山梨酸、安赛蜜、柠檬黄、日落黄、觅菜红、胭脂红、赤藓红、新红、酸性红、诱惑红、罗丹明B)的方法。样品经前处理后,以甲醇-0.02 mol/L乙酸铵溶液梯度洗脱,采用紫外检测器检测,检测波长为240 nm,流速为1.0 mL/min。12种食品添加剂在0.5~30 mg/L范围内线性关系良好,回归系数都在0.999以上,方法加标回收率为93.1%~106.9%,相对标准偏差为1.4%~8.2%,检出限为0.07~0.63 mg/kg。     

钼酸铵分光光度法测定地表水总磷含量的样品采集与预处理

探讨钼酸铵分光光度法测定地表水总磷含量的样品采集与预处理方法。采用钼酸铵分光光度法测定地表水总磷含量时,水体中的泥沙对测定结果影响很大,正确采集样品及去除浊度十分重要。分别针对枯水期和丰水期水样,研究了自然沉降、过筛、离心或抽滤(20μm或0.45μm滤膜)5种采样方式和直接消解测定、浊度–色度补偿、消解后抽滤测定3种预处理方式对地表水总磷测定结果的影响。结果表明:自然沉降是最合理的采样方式,枯水期样品可直接消解测定,丰水期样品可消解抽滤后测定。     

微量分析法用于火焰原子吸收光谱测定高含量钠

将微量分析方法与火焰原子吸收法结合用于测定高钠样品中的钠含量。通过选择合适的钠吸收谱线,确定了标准曲线和测定参数,建立了适合测定高钠样品的方法。方法的线性工作范围为0~5 mg/L,方法检出限为0.02 mg/L,RSD为0.5%。运用方法测试含钠有机物和无机钠盐中不同浓度的钠含量,结果表明,实际样品中钠含量的测定值与计算值间的绝对误差小于0.3%,相对误差小于1%,回收率99.2%~100.6%。     

电感耦合等离子体质谱法测定PM2.5中的重金属元素

采集环境空气细颗粒物(PM2.5)样品,建立了电感耦合等离子体质谱法(ICP-MS)同时测定PM2.5中10种重金属元素的方法。样品经5%HNO_3超声浸提,过滤后,用ICP-MS测定。结果表明:10种重金属元素的检出限在0.030μg/L~0.13μg/L之间;线性关系良好,精密度为0.82%~4.3%,回收率为80.1%~113.0%。该方法快速、准确,可用于PM2.5中重金属元素的测定。     

离子电极在非Nernst区的响应方程研究——PVC-AD电极在低浓区的应用

为使PVC-AD电极能满足生活饮用水和地表水中阴离子表面活性剂含量(低至0.02mg/L)测定的要求,研究了电极在非Nernst区的响应,推导了新的响应方程,建立了定量分析方法,并进行了实际样品的测定。     

超高效液相色谱-串联质谱法快速测定地表水中联苯胺、苦味酸、甲萘威、阿特拉津和溴氰菊酯

建立了一种经简单过滤即可直接进样的超高效液相色谱-串联质谱（UPLC-MS/MS）分析方法,可快速测定地表水中联苯胺、苦味酸、甲萘威、阿特拉津和溴氰菊酯5种有机物的残留。样品经0.2 μ m针式滤头过滤除去颗粒性杂质后,进行UPLC-MS/MS分析,采用UPLC HSS T₃色谱柱,2 mmol/L乙酸铵甲醇溶液和2 mmol/L乙酸铵水溶液作为流动相进行梯度洗脱,电喷雾离子源电离,正、负离子切换多反应监测模式进行定性和定量分析。5种目标化合物分别在0.10~10.0 μ g/L或1.00~100 μ g/L范围内线性关系良好,相关系数为0.996~0.999,方法的检出限为0.01~0.22 μ g/L;高、中、低3个添加水平的回收率为81.4%~113%,相对标准偏差为0.84%~14.0%。利用该方法对杭州市部分河流和水库的地表水样品进行分析,其中阿特拉津和溴氰菊酯在部分水样中有阳性检出。结果表明,该方法简便快捷、灵敏准确,适用于地表水样品中联苯胺、苦味酸、甲萘威、阿特拉津和溴氰菊酯的快速测定。     

电热板蒸发–重量法测定水中全盐量

建立了电热板蒸发–重量法测定水中全盐量的方法。采用电热板对过滤后的水样进行蒸发预处理,然后以重量法测定样品中的全盐量。取样体积为100 m L,以陶瓷蒸发皿为容器,恒重指标为质量偏差±0.5 mg,设置电热板蒸发温度为350℃,以差减重量法测定水中全盐量,方法线性范围为40~2 000 mg/L,检出限为10 mg/L,3种质量浓度水平实际样品的加标回收率在90.2%~110%之间,样品测定结果的相对标准偏差为2.8%~5.2%(n=6),有证标准物质测定结果与标准值相对误差为–1.9%~2.1%。该方法准确度高、稳定性好,适用于水中全盐量的测定。     

乙肝解毒胶囊中5种有效成分的胶束电动色谱-质谱联用法测定

建立了胶束电动色谱-电喷雾电离质谱联用法同时测定乙肝解毒胶囊中的小檗碱、巴马汀、药根碱、黄芩苷、大黄素5种药效成分含量的分析方法。使用未涂层石英毛细管,以30 mmol/L月桂酸-70mmol/L氨水溶液(含20%乙腈,pH10.0)为缓冲液、70%异丙醇(含3 mmol/L乙酸)为鞘液。结果表明,在18 min内各组分达到基线分离,小檗碱、巴马汀、药根碱、黄芩苷、大黄素的线性范围分别为0.02~20、0.05~15、0.05~10、2.0~500、0.02~15 mg/L,检出限分别为0.007、0.02、0.02、0.60、0.006 mg/L。样品的加标回收率为95%~104%,相对标准偏差均小于3.9%。方法简便、快速、灵敏,已成功用于乙肝解毒胶囊中小檗碱、巴马汀、药根碱、黄芩苷、大黄素含量的同时测定。     

基于钼酸盐光度法测定总磷的浊度去除方法

采取新的浊度去除方法,改进了测定总磷的钼酸盐光度法。测定过程中,消解液的浊度会对测定结果产生干扰。通过比较机械过滤法和试剂补偿法的浊度校正效果,建立了中速定性滤纸单次机械过滤的浊度去除方法,确定了最佳去除条件:控制待滤液温度不高于30℃,清洗纯水的体积不少于20 m L。选择消解液具有浊度干扰项的6种代表性水样,分别进行平行测定和加标回收试验,方法检出限为0.008 mg/L,测定结果的相对标准偏差为2.8%~7.9%(n=6),加标回收率为92.0%~106%。该方法灵敏度、准确度高,精密度良好,与现行国标法相比,试剂消耗量少,分析效率高,能够满足多种水环境样品中总磷的测定要求。     

Speciation analysis of mercury in seawater from the lagoon of Venice by on-line pre-concentration HPLC-ICP-MS

A method based on the coupling of HPLC with ICP-MS with an on-line pre-concentration micro-column has been developed for the analysis of inorganic and methyl mercury in the dissolved phase of natural waters. This method allows the rapid pre-concentration and matrix removal of interferences in complex matrices such as seawater with minimal sampling handling. Detection limits of 0.07 ng L(-1) for inorganic mercury and 0.02 ng L(-1) for methyl mercury have been achieved allowing the determination of inorganic mercury and methyl mercury in filtered seawater from the Venice lagoon. Good accuracy and reproducibility was demonstrated by the repeat analysis of the certified reference material BCR-579 coastal seawater. The developed HPLC separation was shown to be also suitable for the determination of methyl mercury in extracts of the particulate phase.     

基于壳聚糖的浊度法测定超滤膜截留率

研究了以壳聚糖为基准物、浊度法测定超滤膜截留率的方法。以氢氧化钠为沉淀剂,用浊度法分别对6种不同相对分子质量的壳聚糖浓度进行检测,探讨了壳聚糖相对分子质量与氢氧化钠浓度等因素对浊度的影响。结果表明,壳聚糖含量在25~1 000 mg/L范围内与浊度呈现良好的线性关系,线性相关系数r~2≥0.996,检出限在2.1~4.8mg/L之间,样品加标回收率为82.1%~122%。测量结果的相对标准偏差为0.75%~8.7%(n=6)。该法快速、简便,可为超滤膜研究、生产、改性及应用等提供理论指导。     

Determination of selenium in blood serum by inductively coupled plasma atomic emission spectrometry with pneumatic nebulization

The possibility of determining selenium in blood serum using inductively coupled plasma emission spectrometry with conventional pneumatic nebulization was studied. A high-resolution spectrometer (SBW=6 pm) with laterally viewed ICP was employed. Analysis with conventional pneumatic nebulization could overcome laborious and demanding digestion, which is necessary for hydride generation. A pressure digestion with nitric acid at 160 degrees C was sufficient to decrease the carbon content in the serum sample to 5%-10% of its original value. Spectral interference of the CN band was observed and mathematically corrected. It was found that the carbon-induced selenium line emission enhancement occurred even under ICP optimized conditions. A method of determination was developed and applied to the analysis of blood serum. True limit of detection in real samples is 0.01-0.02 mg/L and the limit of quantification (RSD 10%) is 0.03-0.07 mg/L using Se I 196.090 nm line at an integration time of 10-2 s. The method was tested by analysis of porcine blood serum and the serum reference material Seronorm MI 0181.     

壳聚糖-铜复合物修饰电极对过氧化氢电催化性能的研究

将壳聚糖与铜盐通过配位结合制得壳聚糖-铜复合物(CTS-Cu),并用其修饰玻碳电极,使用循环伏安法和计时安培法研究了该修饰电极对H2O2的电催化性能,对其催化机理进行了探讨.优化的实验条件为:以0.1 mol/L.磷酸缓冲溶液(PBS,pH 7.0)为反应介质,CTS-Cu修饰液中的铜离子浓度为6 mmol/L,工作电...     

悬浮物测定的质量控制方法

为完善现行国标法GB 11901–1989《水质悬浮物的测定重量法》中质量控制与质量保证相关内容,促进悬浮物标准品的研发,利用高岭土研制的标准溶液建立了悬浮物测定的质量控制方法。根据水样的属性,取样体积范围在50 m L~200 m L区间,采用水系0.45μm滤膜和三联抽滤装置对水样进行预处理操作,以重量法测定水样悬浮物的含量。确定方法的空白测定值稳定于上下警告线内波动,检出限为5 mg/L,样品6次测定结果的相对标准偏差小于10%,标准样品10次测定相对误差在±10%内,满足分析质量控制要求。     

A solid-phase spectrophotometric method for the determination of sulphathiazole

A spectrophotometric method for the determination of sulphathiazole (ST) has been developed, based on solid-phase spectrophotometry. The influence of experimental variables on fixation on Sephadex SP C-25 is discussed. The applicable concentration range is 0.10-10.00 mg/l., with a relative standard deviation of 0.62% and a detection limit of 0.02 mg/l. The accuracy and precision of the method are reported. The proposed method has been satisfactorily applied to the determination of sulphathiazole in pharmaceuticals.     

Simultaneous spectrophotometric kinetic determination of four flavor enhancers in foods with the aid of chemometrics

A sensitive kinetic spectrophotometric method was developed for the determination of four flavor enhancers--maltol, ethyl maltol, vanillin, and ethyl vanillin--in food samples. The method was based on the reduction of iron(III) by the four analytes in a sulfuric acid medium (0.012 mol/L), and the subsequent interaction of iron(II) with hexacyanoferrate(III) to form the strongly colored Prussian blue complex, which exhibited an absorption maximum at 800 nm. The optimized method had linear calibrations over the concentration ranges of 0.2-2.8 mg/L for maltol, ethyl maltol, and vanillin, as well as 0.2-1.8 mg/L for ethyl vanillin; the corresponding detection limits were 0.07, 0.07, 0.06, and 0.06 mg/L, respectively. Calibration models were constructed from the original and first-derivative spectral data with the use of partial least-squares (PLS) and principal component regression chemometrics methods. Ultimately, the proposed analytical procedure was successively applied for the determination of the four compounds in commercial food samples with the use of a PLS calibration based on the first-derivative spectral data. The results were comparable with those from a reference HPLC method.     

快速溶剂萃取-气相色谱法同时测定含脂羊毛中的28种有机氯拟除虫菊酯杀虫剂的残留量

建立了快速溶剂萃取-气相色谱法同时测定含脂羊毛中28种有机氯、拟除虫菊酯杀虫剂残留量的方法。在80 ℃、10.34 MPa条件下用正己烷饱和的乙腈快速提取样品,提取物经冷冻除脂、浓缩、固相萃取净化处理后直接用气相色谱分析。结果表明:16种有机氯杀虫剂在0.005～1.0 mg/L范围内,9种拟除虫菊酯杀虫剂及三氯杀螨醇、三氯杀螨砜在0.01～2.0 mg/L范围内,氟氯苯菊酯在0.02～4.0 mg/L范围内,其峰面积与质量浓度呈良好的线性关系。28种有机氯、拟除虫菊酯杀虫剂的平均回收率为67.2%～107.7%,相对标准偏差为2.6%～29.0%。结果表明：该方法具有操作简便、快速方便、灵敏度高等特点,完全可满足含脂羊毛中28种有机氯拟除虫菊酯杀虫剂残留量初筛检测的要求。     

Simultaneous and Fast Detection of Anions in Snow Using Short Tube by Capillary Zone Electrophoresis

A capillary zone electrophoresis (CZE) method applied short-effective length of capillary (11 cm) and low separation voltage (5 kV) was developed for the fast and quantitative determination of Cl m , $ {\rm NO}_2^ - $ , $ {\rm SO}_4^{2 - } $ , $ {\rm NO}_3^ - $ , $ {\rm HCO}_3^ - $ in snow sample. Baseline separation of inorganic anions and organic anions was achieved within 55 s. Indirect absorbance detection of anions was accomplished with a chromate - based background electrolyte modified with cetyltrimethylammonium bromide (CTAB) and acetonitrile at pH 9.5. The effect of the pH, the concentration of electrolyte and modifiers on the resolution was investigated. The application of electrokinetic injection using butyric acid as internal standard created the described method fast, sensitive, and quantitative, with good relative standard deviation (RSD), for migration times from 0.1 to 0.3% and for peak areas from 1.8 to 4.0%. The limits of detection (LOD) were 0.03 mg L m 1 Cl m , 0.1 mg L m 1 $ {\rm NO}_2^ - $ , 0.07 mg L m 1 $ {\rm SO}_4^{2 - } $ , 0.08 mg L m 1 $ {\rm NO}_3^ - $ , 0.05 mg L m 1 F m , and 0.2 mg L m 1 $ {\rm HCO}_3^ - $ , respectively. Standard addition recoveries of Cl m , $ {\rm NO}_2^ - $ , $ {\rm SO}_4^{2 - } $ , $ {\rm NO}_3^ - $ , F m , and $ {\rm HCO}_3^ - $ in snow sample were between 91 and 104%. This method has been shown promising results for the determination of small anions in snow sample.