盐析分相微萃取-液相色谱法测定水中痕量五氯酚

本文采用正丁醇作萃取剂,盐析分相微萃取样品处理方法富集水中五氯酚,反相高效液相色谱法测定水中痕量五氯酚。考察了不同萃取剂、盐析效应和pH值对萃取效果的影响。该方法加标回收率为87.41%,方法检出限为0.00467mg/L,相对标准偏差为2.09%。该萃取方法可有效富集水中痕量五氯酚。     

超高效液相色谱-质谱联用法测定塑料食品包装中防霉剂

建立了液质联用法测定不同塑料材质食品包装材料中防霉剂的分析方法。以甲醇为萃取溶剂,采用超声提取法,提取塑料食品包装中五氯苯酚、双氯酚、邻苯基苯酚以及4-氯-3,5-二甲基苯酚四种防霉剂,萃取液氮吹浓缩后定容,用超高效液相色谱-质谱串联法分析,检测时间为4.5分钟。结果表明:该方法以甲醇超声萃取30分钟为前处理方法,采用C18色谱柱,以甲醇-水为流动相,负离子多反应监测模式(MRM)测定,外标法定量,方法检出限为0.01mg/Kg,加标回收率为80.7%-94.5%,重复测量结果之间的相对标准偏差为2.1%。该方法具有快速、方便、准确度高等优点。     

液-液小体积萃取GC-MS方法快速测定地表水中的硝基苯类、氯苯类及邻苯二甲酸酯类化合物

建立了一种以容量瓶为萃取容器的液-液小体积萃取GC-MS快速测定地表水中硝基苯类、氯苯类及邻苯二甲酸酯类化合物的分析方法。该方法具有操作简单快速、适用性广和试剂用量很少等特点。当萃取试剂用量为1mL时(约为一般常规液液萃取用量的数十分之一),萃取富集效率可达100倍,回收率为76%～120%,相对标准偏差为3%～8%,检出限为0.2～0.9μg/L。对实际地表水水样中的硝基苯、氯苯类及邻苯二甲酸酯化合物进行了定性定量分析,结果令人满意。     

UPLC同时测定决明子中橙黄决明素、大黄素、大黄酚和大黄素甲醚的含量

建立UPLC同时测定决明子中橙黄决明素、大黄素、大黄酚和大黄素甲醚含量的方法,采用ACQUITY UPLCBEH-C18色谱柱(2.1 mm×50 mm×1.7μm),乙腈和0.1%磷酸水溶液为流动相,采用梯度洗脱,流速为0.6 mL/min,检测波长为284nm。结果表明橙黄决明素、大黄素、大黄酚和大黄素甲醚分别在3.002～30.02μg/mL、2.500～25.00μg/mL、10.430～104.30μg/mL和5.916～59.16μg/mL的浓度范围内均有良好的线性关系(r=0.999 9),回收率均大于95%,RSD均小于2%。该方法快速,准确,重现性好,可用于测定决明子中橙黄决明素、大黄素、大黄酚和大黄素甲醚的含量。     

2,3,4-三氯苯甲醚标准物质研制与定值

研制了2,3,4-三氯苯甲醚标准物质,介绍了其制备与定值方法。将制备的2,3,4-三氯苯甲醚标准物质分装成500瓶样品,随机抽取其中11瓶做均匀性检验,经F检验和t检验,结果表明在95%置信范围内样品均匀性良好。按短期与长期稳定性分别进行稳定性检验,结果表明在常温20℃下,2,3,4-三氯苯甲醚的稳定期不少于12月。采用液相色谱法和差示扫描量热法2种不同原理的方法对2,3,4-三氯苯甲醚标准物质纯度定值及不确定度评定,并采用液相色谱标准添加的方法确认了2,3,4-三氯苯甲醚标准物质中的主要杂质2,3,6-三氯苯甲醚。定值结果为99.56%± 0.40%（k=2）。     

CoMoN_x/CNTs催化剂氯代硝基苯选择性催化加氢反应性能

采用等体积浸渍法结合程序升温还原技术制备出一系列负载型过渡金属氮化物催化剂,并利用XRD、BET、TG-DSC等手段对催化剂进行表征。将此催化剂用于邻氯硝基苯液相催化加氢。结果表明,单组分MoN/CNTs催化剂的活性较低,氯代硝基苯转化率为57.5%,双组份CoMoN_x/CNTs的活性较高,氯代硝基苯转化率为89.8%,添加了稀土La后CoMoN_x/CNTs催化剂活性改善不明显,但对o-CAN选择性达到了99.3%。     

气相色谱法测定水中痕量邻氯酚和对氯酚

介绍了测定水中痕量邻氯酚和对氯酚的气相色谱法,采用XAD—7树酯富集、PEG—20M柱分离后,FID检测。邻氯酚和对氯酚的最低检出溶度分别为4.8ppb和5.1ppb。5升ppt级浓度的水样,富集500倍后测定,邻氯酚和对氯酚的相对标准偏差分别为4.4％和5.2％,回收率为91.5％—98.8％。方法灵敏、准确,操作简便、快速,适用于地面水和自来水中痕量邻氯酚和对氯酚的测定。     

加速溶剂萃取-GC-MS法检测食品接触材料——纸、纸板、木材和木制品中的6种氯酚类物质残留

建立了检测食品接触材料——纸、纸板、木材和木制品中含氯酚(CPs)残留量的气相色谱-质谱(GC-MS)分析方法。采用加速溶剂萃取(ASE)法为样品前处理手段,优化了萃取溶剂、萃取温度、静态萃取时间、冲洗体积和萃取循环次数等实验参数。优化结果为:以二氯甲烷为萃取溶剂,萃取温度为150℃,静态萃取时间为10 min,冲洗体积为(占萃取罐体积的)60%,萃取循环次数为1次。结果表明:6种CPs在0.05～2.0μg/mL质量浓度范围内具有良好的线性关系(R>0.99);平均回收率在86.8%～108.8%之间(n=6);相对标准偏差(RSD)为1.8%～14.2%(n=6);方法的检测限为0.01 mg/kg。研究表明该方法高效、简便、快捷、灵敏、准确可靠,可用于实际样品的CPs残留量的监测。     

环状六氯三聚磷腈的合成

采用氯化铵和五氯化磷为原料,氯苯为溶剂,无水氯化镁加吡啶为催化剂,合成了环状六氯三聚磷腈。在较佳工艺条件下,产品收率可达85.1％。氯苯的回收率>96％。     

气相色谱-质谱法测定食品接触耐高温材料中氯苯和对二氯苯迁移量

目的利用气相色谱-质谱联用法测定食品接触耐高温材料中氯苯类物质(氯苯、对二氯苯等)的迁移量。方法从水基、酸性、醇类、油基等食品模拟物的迁移试验中得到的样品,通过正己烷或甲醇等有机溶剂萃取后,提取液中的氯苯类物质经由键合聚乙二醇的毛细管柱分离,最终在质谱中进行检测分析。结果在优化萃取溶剂、色谱柱等检测条件下,该方法可有效测定食品模拟物中氯苯、对二氯苯等物质的迁移量,在0.05~50 mg/kg(水性模拟物)或0.2~50 mg/kg(油性模拟物)的范围内线性良好,检出限可达到0.02 mg/kg(水性模拟物)或0.1 mg/kg(油性模拟物),回收率在87.6%~113.2%之间,相对标准偏差小于10%(n=6)。结论建立了食品接触材料中氯苯和对二氯苯迁移量的气相色谱-质谱联用方法,该方法简单、快捷、准确,满足了食品接触材料中氯苯类物质日常检验的要求。     

地表水中有机磷农残测定的前处理方法比较

分别采用液液萃取法和固相萃取法提取地表水样品中的有机磷农药残留。液液萃取法的方法检出限为0.05~0.2 ng/mL,加标回收率为86%~103%,相对标准偏差为2%~7%;固相萃取法的方法检出限为0.03~0.05 ng/mL,加标回收率为49%~118%,相对标准偏差为5%~18%。液液萃取法处理不同类型基体水样的测试稳定性较好,固相萃取法则对于洁净环境水体中痕量有机磷农药残留的富集更为适用。     

火焰原子吸收分光光度法测定环境水样中钾和钠

采用火焰原子吸收分光光度法测定环境水样中钾和钠的含量,通过对不同波长条件下钾钠吸光度的比较,选择出最佳灵敏线应用于本机分析试验,过程简单,效果十分理想。方法灵敏度高、线性关系良好、结果准确稳定,检出限钾为0.005mg/L、钠为0.008mg/L。应用此方法测定2种水样中的钾和钠,相对标准偏差1.2%～1.9%,回收率95.2%～103.2%。     

Accelerated solvent extraction followed by on-line solid-phase extraction coupled to ion trap LC/MS/MS for analysis of benzalkonium chlorides in sediment samples

Benzalkonium chlorides (BACs) were successfully extracted from sediment samples using a new methodology based on accelerated solvent extraction (ASE) followed by an on-line cleanup step. The BACs were detected by liquid chromatography/ion trap mass spectrometry (LC/MS) or tandem mass spectrometry (MS/MS) using an electrospray interface operated in the positive ion mode. This methodology combines the high efficiency of extraction provided by a pressurized fluid and the high sensitivity offered by the ion trap MS/MS. The effects of solvent type and ASE operational variables, such as temperature and pressure, were evaluated. After optimization, a mixture of acetonitrile/water (6:4 or 7:3) was found to be most efficient for extracting BACs from the sediment samples. Extraction recoveries ranged from 95 to 105% for C12 and C14 homologues, respectively. Total method recoveries from fortified sediment samples, using a cleanup step followed byASE, were 85% for C12BAC and 79% for C14BAC. The methodology developed in this work provides detection limits in the subnanogram per gram range. Concentrations of BAC homologues ranged from 22 to 206 microg/kg in sediment samples from different river sites downstream from wastewater treatment plants. The high affinity of BACs for soil suggests that BACs preferentially concentrate in sediment rather than in water.     

Comparison of ASE and SFE with Soxhlet, Sonication, and Methanolic Saponification Extractions for the Determination of Organic Micropollutants in Marine Particulate Matter

The methods of accelerated solvent extraction (ASE) and supercritical fluid extraction (SFE) of polycyclic aromatic hydrocarbons (PAHs), aliphatic hydrocarbons, and chlorinated hydrocarbons from marine samples were investigated. The results of extractions of a certified sediment and four samples of suspended particulate matter (SPM) were compared to classical Soxhlet (SOX), ultrasonication (USE), and methanolic saponification extraction (MSE) methods. The recovery data, including precision and systematic deviations of each method, were evaluated statistically. It was found that recoveries and precision of ASE and SFE compared well with the other methods investigated. Using SFE, the average recoveries of PAHs in three different samples ranged from 96 to 105%, for ASE the recoveries were in the range of 97-108% compared to the reference methods. Compared to the certified values of sediment HS-6, the average recoveries of SFE and ASE were 87 and 88%, most compounds being within the limits of confidence. Also, for alkanes the average recoveries by SFE and ASE were equal to the results obtained by SOX, USE, and MSE. In the case of SFE, the recoveries were in the range 93-115%, and ASE achieved recoveries of 94-107% as compared to the other methods. For ASE and SFE, the influence of water on the extraction efficiency was examined. While the natural water content of the SPM sample (56 wt %) led to insufficient recoveries in ASE and SFE, quantitative extractions were achieved in SFE after addition of anhydrous sodium sulfate to the sample. Finally, ASE was applied to SPM-loaded filter candles whereby a mixture of n-hexane/acetone as extraction solvent allowed the simultaneous determination of PAHs, alkanes, and chlorinated hydrocarbons.     

离子色谱法测定地表水中的溴酸盐

建立了单柱阴离子色谱测定地表水中溴酸根的方法,并对实际水样进行了测定。溴酸盐浓度在0．01—4．0mg／L范围内与峰面积线性回归相关系数O．9993,检出限为O．02mg／L,保留时间和峰面积相对标准偏差分别为0．13％和0．92％,回收率为96．2—103．5％。     

Analysis of hydrazine in drinking water by isotope dilution gas chromatography/tandem mass spectrometry with derivatization and liquid-liquid extraction

A new isotope dilution gas chromatography/chemical ionization/tandem mass spectrometric method was developed for the analysis of carcinogenic hydrazine in drinking water. The sample preparation was performed by using the optimized derivatization and multiple liquid-liquid extraction techniques. Using the direct aqueous-phase derivatization with acetone, hydrazine and isotopically labeled hydrazine-(15)N2 used as the surrogate standard formed acetone azine and acetone azine-(15)N2, respectively. These derivatives were then extracted with dichloromethane. Prior to analysis using methanol as the chemical ionization reagent gas, the extract was dried with anhydrous sodium sulfate, concentrated through evaporation, and then fortified with isotopically labeled N-nitrosodimethylamine-d6 used as the internal standard to quantify the extracted acetone azine-(15)N2. The extracted acetone azine was quantified against the extracted acetone azine-(15)N2. The isotope dilution standard calibration curve resulted in a linear regression correlation coefficient (R) of 0.999. The obtained method detection limit was 0.70 ng/L for hydrazine in reagent water samples, fortified at a concentration of 1.0 ng/L. For reagent water samples fortified at a concentration of 20.0 ng/L, the mean recoveries were 102% with a relative standard deviation of 13.7% for hydrazine and 106% with a relative standard deviation of 12.5% for hydrazine-(15)N2. Hydrazine at 0.5-2.6 ng/L was detected in 7 out of 13 chloraminated drinking water samples but was not detected in the rest of the chloraminated drinking water samples and the studied chlorinated drinking water sample.     

Speciation of Cr(III) and Cr(VI) after column solid phase extraction on Amberlite XAD-2010

A speciation procedure for Cr(III) and Cr(VI) based on column solid phase extraction on Amberlite XAD-2010 and flame atomic absorption spectrometry combination. Cr(VI) was quantitatively recovered on Amberlite XAD-2010 resin at pH range of 2.0-3.0 as its diethyldithiocarbamate complex, while the recoveries of Cr(III) was below 5%. The influences of the various parameters including amounts of the reagents, eluent type and its volume, sample volume, etc., on the quantitative recoveries were examined. The interference of matrix and coexistent elements for method were studied. The detection limit (corresponding to three times the standard deviation of the blank) and the enrichment factor for Cr(VI) were found to be 1.28 microg/L and 25, respectively. To verify the accuracy of the method, drinking water certified reference material (CRM-TMDW-500) was analyzed and the results obtained were in good agreement with the certified value. The proposed method has been successfully applied to the speciation of Cr(III) and Cr(VI) in water samples and preconcentration of total chromium in environmental samples.     

液液萃取-GC/MS法分析地表水中的多氯联苯

建立了液液萃取-GC/MS联用分析地表水中的多氯联苯的方法,并对实际水样进行了测定。各目标物的线性回归R值均大于0.999,MDL为0.08-3.9ng/L,RSD为0.25%-6.2%,回收率为87.6%-113%。     

分散液液微萃取--气相色谱法测定海水中的邻苯二甲酸酯

本文以分散液液微萃取作为样品的前处理技术,建立了气相色谱-氢火焰离子化检测器分析海水中邻苯二甲酸酯的新方法。优化了分散液液微萃取的萃取条件,6种邻苯二甲酸酯线性范围在1.0-50.0μg/mL之间,R≥0.9953,回收率在92.5%~106.4%之间,最低检测限为0.15μg/mL。将方法应用于海水中邻苯二甲酸酯类的检测,易于操作,分析结果可靠。     

离子色谱法测定饮用水中的磷酸盐

建立了单柱阴离子色谱测定饮用水中磷酸盐的方法,并对实际水样进行了测定。磷酸盐浓度在0.1-4.0mg/L范围内与峰面积线性回归相关系数0.9992,检出限为0.02mg/L,保留时间和峰面积相对标准偏差分别为0.09%和0.52%,回收率为96.2-102.4%。