固相萃取-气相色谱-质谱法测定地下水中多环芳烃

提出了固相萃取-气相色谱-质谱法测定地下水中16种多环芳烃的方法。样品经ENVIC18固相萃取柱富集,依次用丙酮5 mL和二氯甲烷10 mL将16种多环芳烃从固相萃取柱上洗脱,用K-D浓缩器浓缩后,供气相色谱-质谱仪测定。纯水或自来水经固相萃取处理后,再用于配制标准溶液并绘制标准曲线。16种多环芳烃的检出限(3S/N)均小于2.0 ng.L-1。用该法分析地下水样品,所得结果的相对标准偏差(n=7)小于14.0%,加标回收率在84.3%~112.3%之间。     

超声萃取-气相色谱法测定土壤中石油烃

采用探头式超声波发生器萃取-气相色谱-火焰离子检测法(GC-FID)测定土壤中33种石油烃(C8~C40)。采用正交试验考察了萃取剂及其用量、超声时间和萃取次数等4个因素对土壤中石油烃的萃取效果的影响,得到最佳萃取条件为:10.00g样品用30mL二氯甲烷超声萃取10min,萃取2次。33种石油烃的线性范围在500mg·L~(-1)内,检出限(3s)为0.10~0.40mg·L~(-1)。加标回收率为83.2%~106%,测定值的相对标准偏差(n=7)为0.80%~5.5%。     

固相萃取富集/气相色谱法测定烟草中的9种有机酸

建立了用硫酸甲醇甲酯化衍生-固相萃取富集/气相色谱测定烟草中9种有机酸的方法,首次实现了强酸介质中有机酸酯的固相萃取。烟草样品用硫酸-甲醇进行甲酯化衍生,衍生生成的有机酸酯用MCIGEL反相树脂分离富集,萃取液用甲醇洗脱后进行气相色谱分析,采用DB-5毛细管色谱柱,进样量1.0μL,不分流进样;检测器温度250℃。方法可同时准确测定烟草样品中乳酸、草酸、丙二酸、乙酰丙酸、苹果酸、柠檬酸、棕榈酸、硬脂酸、亚油酸的含量,各有机酸的加标回收率为92.2%~102.6%,相对标准偏差为2.4%~3.2%,定量下限为0.20~0.36 mg/L。该方法准确、灵敏度高,能够满足实际样品的测定要求。     

气相色谱检测水中硝基苯分析方法的优化

对水中硝基苯气相色谱检测方法进行优化。用正己烷代替甲苯进行硝基苯萃取和标准溶液配制。在优化的实验条件下,对水中硝基苯进行定量分析,线性方程为y=0.35x+0.69,相关系数r=0.999 99,检出限为0.19μg/L。用该法对实际样品进行测定,测定结果的相对标准偏差为0.9%~3.5%(n=8),加标回收率为98.1%~105.0%。方法优化后精密度、准确度满足标准方法要求,可以用于水中硝基苯的检测分析。     

滤膜吸附结合超声辅助分散液液微萃取/高效液相色谱法测定空气中溴氰菊酯残留

建立了滤膜吸附结合超声辅助分散液液微萃取与高效液相色谱(HPLC)联用测定空气中溴氰菊酯残留的方法。空气样品用甲醇-水(1∶4)混合溶液提取,加入三氯甲烷进行微萃取,超声,离心,得到沉积相,进行HPLC分析。溴氰菊酯在5~1 000μg/L范围内线性关系良好,相关系数(r)为0.999 8,富集倍数达520倍。当空气样品的加标浓度为10,50,100μg/L时,加标回收率为78.6%~106.7%,相对标准偏差(RSD)为2.2%~4.3%。空气样品中溴氰菊酯的检出限为1μg/L,最低检出浓度为0.04μg/m~3。该方法具有简便快捷、准确灵敏、萃取效率高、有机溶剂消耗少等优点,可用于空气中溴氰菊酯残留的测定。     

微滴液相微萃取技术用于气相色谱-质谱法分析药品中的酞酸酯和对羟基苯甲酸酯

用微滴液相微萃取(SDME)与气相色谱-离子阱质谱联用测定药品中的酞酸酯和对羟基苯甲酸酯。考察了萃取溶剂的种类及用量、微液滴在样品溶液中的深度、萃取时间及搅拌子的搅拌速度对微滴液相微萃取效果的影响。优化的萃取条件:萃取溶剂为1.5 μL甲苯,微液滴在样品溶液中的深度为0.8 cm,搅拌子的搅拌速度为1000 r/min,萃取时间为20 min。该方法的线性范围为0.032~80 mg/L,检出限为0.6 μg/L~1.28 mg/L,加标回收率为95.85%~148.85%,相对标准偏差为3.9%~14.9%。     

国标法测定地表水中阴离子表面活性剂方法优化

对GB/T 7494–1987测定地表水中阴离子表面活性剂含量的方法进行优化。对萃取次数、磷酸二氢钠溶液反洗以及pH调节等进行了试验研究,将萃取用的三氯甲烷总量降为25 mL,两次萃取定容后一次反洗。结果表明,萃取两次可以满足分析需求,反洗能够有效去除亚硝酸盐氮等离子干扰,中性地表水样品无需调节pH,非中性样品须调为中性后测定。方法优化后线性良好,线性相关系数大于0.999,检出限为0.012 mg/L。测定结果的相对标准偏差为0.8%~3.3%(n=6),加标回收率为92.0%~110.0%。优化后方法满足地表水分析要求,能有效降低三氯甲烷用量并简化分析步骤。     

γ-Al2O3-氧化石墨烯吸附材料用于尿液中核苷的检测

用γ-Al₂O₃纳米粒子键合的氧化石墨烯（GO）作为固相萃取吸附剂,与高效液相色谱法联用,建立了一种对人体尿液中4种核苷分离测定的新方法。采用透射电镜（TEM）、热重分析（TGA）及傅里叶红外光谱（FT-IR）对吸附剂进行表征。考察了洗脱液种类、吸附剂用量、样品体积及样品pH值对吸附性能的影响,通过平衡吸附量衡量吸附效果。在最佳萃取条件下,该吸附剂对核苷具有一定的富集能力。胞苷、肌苷、鸟苷在0.10~10 mg/L,尿苷在0.05~10 mg/L范围内呈现良好的线性关系,线性相关系数为0.9967~0.9973,检出限为0.010~0.021 mg/L,日内和日间相对标准偏差分别为0.1%~0.8%和1.0%~3.1%。实际尿样中,4种核苷的加标回收率为71.3%~107.4%,相对标准偏差（n=3）小于4.8%。该方法灵敏度高、精密度和回收率良好,可用于尿液样品中核苷类物质的富集和测定。     

液液萃取-高效液相色谱法同时测定水基胶中17种邻苯二甲酸酯类物质的残留量

采用液液萃取-高效液相色谱法同时测定水基胶中17种邻苯二甲酸酯类物质的残留量。水基胶样品经水分散后,用乙酸乙酯萃取,萃取液离心后,取上层清液过0.45μm有机相滤膜。以DIONEX Acclaim explosives E2柱为分离柱,以不同体积比的乙腈和水的混合溶液为流动相进行梯度洗脱,在检测波长220nm处进行测定。17种邻苯二甲酸酯的质量浓度均在0.4~20.0mg·L-1范围内与峰面积呈线性关系,方法的检出限(3s)在0.024~0.114mg·L-1之间,测定下限(10s)在0.079~0.379mg·L-1之间。加标回收率在89.7%~101%之间,测定值的相对标准偏差(n=5)小于6.0%。     

气质联用法测定豆角中多农药残留及方法应用研究

采用气质联用仪建立了长豆角中27种农药残留的快速检测方法。用乙酸乙酯萃取样品,萃取液浓缩后用二氯甲烷定容,进行GC–MS分析。结果表明,27种农药测定结果的相对标准偏差为5.38%~22.35%(n=6),检出限在0.003 85~0.035 29 mg/kg之间,加标回收率为71.50%~119.30%。用所建方法研究了14种农药在长豆角上喷施后的残留情况。该方法样品处理简单快速,溶剂用量少,可用于长豆角中多种农药残留分析。     

荧光光度法测定地表水、地下水及废水中石油类样品的方法优化

改进了利用荧光分光光度计测定水质石油类样品的分析方法. 水质石油样品采用正己烷提取,经硅酸镁净化后使用荧光分光光度计检测. 经过优化,方法曲线线性在0.999以上,检出限为0.007 mg/L. 经过3种地表水、1种地下水以及2种工业废水的验证,回收率为87.5%~110.0%. 分别使用紫外法、红外法与荧光光度法进行比对,地表水和地下水测定结果相对偏差为5.3%~13.3%,废水测定结果相对偏差为1.7%~19.5%. 经验证,荧光光度法检出限低,灵敏度高,可以作为现有水质石油类监测标准体系的补充.     

毛细管柱气相色谱法测定液化石油气中二甲醚含量

建立毛细管柱气相色谱法测定液化石油气中二甲醚含量的分析方法。采用静止进样法直接进样,用PLOT–Q毛细管色谱柱进行分离,以FID检测器进行检测,外标法进行定量分析。液化石油气中二甲醚的含量(体积分数)在0%~20.0%范围内与其色谱峰面积呈良好线性关系,线性相关系数r=0.999 9,方法检出限为0.05%(体积分数),测定结果的相对标准偏差小于5%(n=6),回收率在98.2%~102.9%之间。该方法与校正面积归一法测定结果相一致。该方法准确、快速、简便,适用于液化石油气中二甲醚含量的检测。     

Determination of benzylsuccinic acid in gasoline-contaminated groundwater by solid-phase extraction coupled with gas chromatography-mass spectrometry

Benzylsuccinic acid (BSA) and methylbenzylsuccinic acid (methyl-BSA) are unambiguous biotransformation products resulting from anaerobic toluene and xylene biodegradation, respectively. A solid-phase extraction method based on polystyrene-divinylbenzene sorbent was developed for the quantitative BSA determination in groundwater samples as an alternative to liquid-liquid extraction. Gas chromatography coupled with mass spectrometry was used for separation and detection. The recovery from spiked 11 groundwater samples was 88 to 100%. The precision of the method, indicated by the relative standard deviation, was +/- 4% and the method detection limit was 0.2 microg/l. The concentration of BSA and methyl-BSA in groundwater samples from anaerobic BTEX (benzene, toluene, ethylbenzene and xylenes)-contaminated sites ranged from below the detection limit (3 microg/l) to 155 microg/l.     

The determination of petroleum hydrocarbons in soil using a miniaturized extraction method and gas chromatography

A gas chromatographic (GC) method for the determination of petroleum hydrocarbons (PH) in the boiling range from 175°C to 525°C (C₁₀?C₄₀ alkane) in soil was evaluated. The extraction was carried out using minimal amounts of acetone and heptane, prior to a clean up with silica gel. The extraction procedure was tested by means of standard solutions of petroleum products and soil samples. The clean up procedure did not have any significant effect on the amounts of petroleum hydrocarbons present and hydrocarbons of natural origin were removed effectively. The recovery of the extraction and clean up procedure for petroleum products in soil was greater than 90%. The standard deviation for the repeatability was estimated to be less than 10% based on multiple analyses of homogenized soil samples. The detection limit for soil was determined to be 10 mg/kg dry matter. Comparing the GC method with the widely used infrared spectrometry (IR) method in combination with a Soxhlet-extraction using Freon-113, the results obtained are equivalent.     

Bromine number determination by coulometric flow-injection titration

The bromine number, the number of grams of bromine which react with 100 grams of a substance under given conditions, is a widely used parameter in the chemical and petroleum industries. A method of performing the bromine number determination by coulometric flow-injection titration, using both sequential injection with sinusoidal flow and single zone techniques, is described. Titrations of olefins, known interfering compounds, and petroleum distillates were performed and compared with the results of conventional bromine number titrations. Analyses yielded a relative standard deviation of 2%. Results compared favorably with those obtained by the conventional method for both pure (97%) olefins and petroleum distillates. The method was found to be insensitive to interference from nitrogen compounds. The CFIT technique combines the advantages of coulometric titrations: controlled generation of reagent, avoidance of reagent standardization requirements and reagent storage and stability problems; with the advantages of FIA: small volume requirements which reduce cost and waste, controllable dilution through flow programming, toxic materials contained within a closed environment, and the capability of being automated.     

Antioxidant Properties and Phenolic Composition of Sideritis Species

The antioxidant properties and phenolic composition of 27 Sideritis species were studied. Plant samples were extracted with petroleum ether using a Soxhlet apparatus. The defatted plant materials were extracted with 70% methanol. Antioxidant activities of the extracts were measured using Fe⁺² induced linoleic acid peroxidation, as indicated by thiobarbituric acid reactive substance (TBARS) production. Free radical scavenging activities were determined based on 1,1-diphenyl-2-picrylhydrazyl radical (DPPH). Results were compared with standard BHT. Total phenol concentration of the extracts was estimated with Folin-Ciocalteu reagent using gallic acid as standard, and phenolic components were quantified by HPLC-DAD.     

环境空气中痕量硝基苯测定方法研究

建立了Tenax富集-气相色谱仪测定环境空气中痕量硝基苯的方法。用Tenax采样管吸附环境空气中的痕量硝基苯,用1.0mL石油醚淋洗解析吸附的硝基苯,用气相色谱-电子捕获检测器进行检测,外标法定量,线性相关系数为0.9992,平均回收率为95.9%～97.1%,RSD不大于5.2%(n=5)。按采样10L计算,检出限为0.0002mg/m3,经实际样品测定完全能满足环境空气中痕量硝基苯监测的要求。     

气相分子吸收光谱法测定地下水中亚硝酸盐氮、氨氮、硝酸盐氮

采用气相分子吸收光谱法测定地下水中的亚硝酸盐氮(NO2^-)、氨氮(NH4^+)、硝酸盐氮(NO3^-)。考察NO2^-,NH4^+和NO3^-测定时的相互干扰,并给出了相应的消除方法。研究结果表明,测定NO2^-时,NH4^+和NO3^-无干扰;NO2^-对测定NH4^+和NO3^-产生干扰,可分别采用分段法和加入2滴10%氨基磺酸溶液的方法消除干扰;对于不含NO2^-或NO2-含量不高的地下水样品,可简化操作步骤直接测定NO3^-。该方法测定结果的相对标准偏差为0.73%~2.74%(n=12),样品加标回收率为97.67%~100.28%。所用检测仪器具有流动注射、自动进样及在线绘制标准曲线的功能,简化了标准方法中的样品前处理过程,减少了样品的损失,实现了自动化分析,大幅提高了检测结果的准确度和工作效率。     

离子色谱法测定地下水中的乙酸根含量

对地下水样品除氯后，选用1．35mmol／LNa2CO3-1．00mmol／LNaHCO3混合溶液作淋洗液，用离子色谱法测定地下水样品中乙酸根的含量，乙酸根浓度在0～5．00mg／L范围内与电导率峰高呈线性关系，线性回归方程为H=15950．6c-442．7，相关系数为0．9994，方法的检出限为0．05mg／L，加标回收率为101％-110％，测定结果的相对标准偏差为2．3％。     

氢化物发生–原子荧光法测定地下水中的镉

建立用氢化物发生–原子荧光法测定地下水中镉的方法。探讨了还原剂硼氢化钾用量及地下水中共存元素干扰对镉测定结果的影响,优化了仪器工作条件。优化的实验条件:介质为2%的盐酸溶液;还原剂为2%的硼氢化钾溶液;载气为氩气,流量为510 mL/min;主阴极灯电流为60 mA。镉的质量浓度在0~10μg/L范围内与荧光强度的峰面积呈良好的线性关系,线性相关系数为0.999 2,检出限为0.03μg/L。测定结果的相对标准偏差为1.24%~6.07%(n=7),加标回收率为90.1%~103.0%。该方法具有较高的灵敏度、精密度和准确度,可用于地下水中镉的测定。