有机氯农药和多氯联苯测定的样品净化方法

介绍了多氯联苯和有机氯农药环境样品的弗罗里硅土小柱、浓硫酸的分离、净化方法。经实际样品测定检验该方法，测定结果可靠。     

加压流体萃取-气相色谱法测定土壤中酞酸酯类化合物

建立了土壤中15种酞酸酯的加压流体萃取-弗罗里硅土柱净化-气相色谱测定方法。就萃取条件探讨了溶剂、温度、时间和循环次数对萃取效率的影响,就净化条件探讨了净化柱和洗脱溶剂对萃取效率的影响。根据研究结果,确定萃取条件以二氯甲烷为萃取溶剂,在萃取温度120℃、压强1 500 psi时,预热5 min,静态提取5 min,循环萃取2次,用体积为60%萃取池体积的萃取溶剂冲洗萃取池,之后用氮气吹扫萃取池90 s;净化条件为萃取溶液过弗罗里硅土固相萃取柱净化后,以正己烷∶丙酮(体积比为5∶1)洗脱。15种酞酸酯类化合物加标回收率为67.1%~124%,方法检出限为0.017~0.048 mg/kg。     

多环芳烃测定中净化方法的研究

对多环芳烃测定中的净化方法进行研究，为了选出最佳净化柱，在一定条件下分别采用硅胶LC-Si、弗罗里LC-Florisil和C18固相萃取净化柱对一定浓度的多环芳烃标准溶液进行净化，测定吸附后流出液多环芳烃浓度，计算吸附率；测定洗脱后流出液多环芳烃浓度，计算洗脱率。测定结果为硅胶、弗罗里和C18固相萃取净化柱对多环芳烃的吸附率分别在87．1％～100％，99．5％～100％和96．6％～100％之间，洗脱率分别在0～106％，78．7％．109％和79．0％～115％之间。结果表明，GC／MS内标法测定样品中多环芳烃使用最理想的净化柱为弗罗里净化小柱，其次为C18净化小柱，最后为硅胶净化小柱。     

底质农残测定中固相柱净化体系的选择

使用固相柱对底质中的7种农残进行净化。结果表明,在相同淋洗条件下,使用氟罗里硅土柱比硅胶柱净化效果好。比较了不同溶剂体系、不同溶剂配比下2种萃取柱的净化效果,选择乙醚-正己烷(体积比1∶2)或丙酮-正己烷(体积比1∶4)作为净化溶剂,较小的收集体积都可满足所有目标化合物的回收率要求;相比较而言,丙酮-正己烷(体积比1∶4)作为净化溶剂,洗脱液的杂质干扰更小,净化效果更好。使用氟罗里硅土柱和丙酮-正己烷(体积比1∶4)对样品净化,方法简单,快速,净化效果好,适合大批量底质样品的前处理净化过程。     

气相色谱法同时测定水中28种多氯联苯单体

采用液液萃取-浓硫酸磺化净化-气相色谱电子捕获检测器同时测定水中28种多氯联苯单体,必要时利用质谱选择离子监测模式定性,考察了萃取溶剂种类和体积及盐析效应对测定的影响,比较了硫酸磺化和弗罗里硅土柱对萃取液的净化效果。方法在1.00μg/L~47.6μg/L范围内线性良好,当取样体积为200 mL时,方法检出限为0.001μg/L~0.002μg/L,基体加标回收率为95.8%~103%,相对标准偏差≤18.7%。     

土壤和沉积物中多氯联苯单体测定的净化方法研究

对浓硫酸净化、铜粉脱硫、氟罗里硅土柱、硅胶柱、石墨碳柱等净化方法在土壤和沉积物多氮联苯单体测定中的应用进行了研究.浓硫酸对多氯联苯单体的净化回收率达92.4％～109％;氟罗里硅土柱用正己烷/丙酮混合溶液淋洗,净化洗脱液体积为8 mL～10 mL时,回收率达85.7％ ～ 108％;硅胶柱用正己烷淋洗,净化洗脱液体积为...     

植物性食品中拟除虫菊酯类农药测定方法的改进

基于色素和含水率两方面的考虑,选用了大米、荼叶和西红柿作为实验介质,在植物性食品中拟除虫菊酯类农药提取条件和净化条件等方面均进行了改进和优化.结果发现,采用正己烷/丙酮混合液(97.5∶2.5,V/V)提取植物性食品中菊酯类农药,40～50℃下超声萃取40min;选用弗罗里硅土和活性炭混合填充物制作层析柱;选用石油醚/乙酸乙酯(9∶1,V/V)作为洗脱溶剂,实验回收率达70%以上,结果令人满意.     

弗罗里硅土净化和凝胶色谱净化在土壤苯并(a)芘测定中的应用

采用ASE萃取-弗罗里硅土净化-HPLC法和ASE萃取-GPC净化-HPLC法测定土壤中苯并(a)芘,并将2种方法的测定结果作比对。试验表明,方法在0.02 mg/L~0.500 mg/L之间线性良好,当取样量为10 g时,弗罗里硅土净化土壤样品方法检出限为8.93×10~(-5)mg/kg,平均加标回收率为72.7%~73.8%,3次测定结果的RSD为4.0%~4.5%;凝胶色谱净化土壤样品方法检出限为1.98×10~(-5)mg/kg,平均加标回收率为88.8%~90.2%,3次测定结果的RSD为2.1%~2.8%。     

快速溶剂提取-气相色谱法测定土壤中石油烃

建立了快速溶剂提取-气相色谱法(氢火焰检测器)测定土壤中石油烃(C_(10)-C_(40))的分析方法。用正己烷/丙酮(V/V=1)的混合溶剂提取土壤中的石油烃(C_(10)-C_(40)),提取液经过浓缩-弗罗里硅土(Florisil)-硅酸镁小柱净化-浓缩后用气相色谱法-氢火焰检测器测定,以C_(10)-C_(40)正构烷烃混合标准溶液为定量校准标准,以色谱峰总面积与混合标准溶液总浓度建立校准曲线进行外标法定量,当称取20.0土壤样品时,方法检出限为6.0mg/kg,经验证方法的精密度和准确度都良好。该方法用于实际土壤中石油烃的测定,测定结果显示加标回收率80%。     

全自动凝胶色谱净化-气相色谱法同时测定淡水鱼类中多氯联苯和有机氯农药等36种残留有机物

建立了淡水鱼类中多氯联苯和有机氯农药等36种半挥发性有机物的同时测定方法。样品用正己烷和丙酮(体积比为1∶ 1)进行提取,提取溶液经凝胶色谱和弗罗里硅土两级净化,浓缩后采用气相色谱法测定,回收率为70.3%~84.8%,检出限为0.05~0.20ng/g。该方法准确度和回收率较好,适合淡水鱼类中多氯联苯和有机氯农药含量的测定。     

Preconcentration technique for the determination of trace elements in natural water samples by ICP-AES

A procedure was developed for the determination of Cd, Cu, Zn, Co, Ni, Mn, Pb and Mo in water samples by inductively coupled plasma atomic emission spectrometry (ICP-AES) after preconcentration on a morpholine dithiocarbamate (mor-DTC) supported by bagasse (Saccharam aphisinaram). The sorbed elements were subsequently eluted with 4,M HNO₃ and the acid eluates were analysed by ICP–AES. The influence of various parameters such as pH, flow rate of sample, eluent concentration, volume of the sample and volume of eluent were investigated to enhance the sensitivity of the present method. A 20,mL disposable syringe served as preconcentration column. Under the optimal conditions Cd, Cu, Zn, Co, Ni, Mn, Pb and Mo in aqueous sample was concentrated about 100-fold. The sorption recoveries of elements were higher than 99.6%. The method is also applied for the analysis of natural and spiked water samples.     

梯度淋洗离子色谱法测定饮用水中6种阴离子

采用离子色谱法同时测定饮用水中F-、Cl-、Br-、NO3-、SO24-、PO34-等6种阴离子,水样经0.22μm滤膜过滤,自动淋洗发生器产生20 mmol/L～40 mmol/L KOH淋洗液梯度洗脱,在流量0.25 mL/min条件下采用IonPac AG19保护柱和IonPac AS19分离柱分离和定量。方法线性良好,6种阴离子的检出限为0.005 mg/L～0.057 mg/L,标准溶液平行测定6次,测定值的RSD在0.5%～2.2%之间,水样加标回收率在83%～106%之间。     

超声提取-离子色谱法测定常见土壤中的高氯酸盐

建立了测定土壤中高氯酸盐的离子色谱法,通过前处理条件优化和色谱条件优化形成准确高效的测定方法,并采集实际土壤样品进行实验验证。称取 1.00 g土壤样品,用20 mL超纯水混合均匀,超声提取40 min,离心后采用水系微孔滤膜过滤的前处理方式,土壤中高氯酸盐的加标回收率最稳定;在淋洗液浓度和流速都满足测定条件的前提下,为了缩短高氯酸盐的保留时间,避免复杂基质干扰,延长淋洗液发生器的使用寿命以及保护色谱柱,选择淋洗液浓度为40 mmol/L,流速为1.0 mL/min。在优化条件下,高氯酸盐的方法检出限为0.04 mg/kg。实际样品加标中高氯酸盐的相对标准偏差为1.9%~8.8%,加标回收率为91.0%~106%,结果表明离子色谱法测定土壤中高氯酸盐简单、灵敏、快速。     

Continuous-flow fractionation of trace metals in environmental solids using rotating coiled columns. Some kinetic aspects and applicability of three-step BCR leaching schemes

The applicability of the three-step BCR leaching scheme to the continuous-flow fractionation of trace metals (TM) using rotating coiled columns (RCC) has been investigated taking soil and sediment reference samples (SRM-2710, CRM-601, BCR-701) as examples. A particulate sample was retained in the rotating column as the stationary phase under the action of centrifugal forces while different eluents, used according to the original and optimised BCR protocols, were continuously pumped through. The whole procedure required 3-4 h instead of at least 50 h needed for the traditional sequential extraction. It has been shown that in comparison with batch sequential extraction procedures (SEP), the recoveries of Cd, Zn, Cu, and Pb at the first stage (most mobile and potentially dangerous acid soluble forms) are somewhat higher, if a dynamic extraction in RCC is used. Nevertheless, the distribution patterns for TM in the first two leachable fractions (acid soluble and reducible forms) are similar in most cases. Since no heating is used in RCC, the recoveries of TM at the third stage (when hydrogen peroxide is applied to oxidize the organic matter) may be incomplete and matrix-dependent. The effect of eluent volume and flow rate on the recovery of TM in different forms has been investigated. It has been shown that the kinetics of heavy metal leaching vary significantly with samples. Hence, investigating the elution profiles can provide additional important information for risk assessment of TM mobilization.     

沉积物中多氯联苯分析的纯化条件优化研究

比较了各种填料层析柱和洗脱液的差别,并根据有机溶剂使用量较少的样品纯化方案,建立了适用低有机质含量水体表层沉积物中不同极性多氯联苯(PCBs)的分析方法.结果表明,该方法检测限在0.11 ng/g～0.35 ng/g(干重)之间,对主要多氯联苯同族体的回收率是77.9%～112.1%.用该法分析了长江中下游水体表层沉积物中的PCBs,质控结果表明,该纯化方法的效果理想.     

Solid phase extraction and determination of Cr(III) by spectrophotometry using cefaclor as a complexing reagent and FAAS

The present study reports on the application of modified groundnut shell as a new, easily prepared, and stable sorbent for the extraction of trace amount of Cr(III) in aqueous solution. 2-Hydroxybenzaldiminoglycine was immobilized on groundnut shells in alkaline medium and then used as a solid phase for the column preconcentration of Cr(III). The elution was carried out with 3 mL of 2 mol?L^?1 HCl. The amount of eluted Cr(III) was determined by spectrophotometry using cefaclor as a complexing reagent and by flame atomic absorption spectrometry (FAAS). Different experimental variables such as pH, amount of solid sorbent, volume and concentration of eluent, sample and eluent flow rate, and interference of other metal ions on the retention of Cr(III) were studied. Under the optimized conditions, the calibration curves were found to be linear over the concentration range of 13–104 and 10–75 μg?L^?1 with a detection limit of 3.64 and 1.24 μg?L^?1 for spectrophotometric method and FAAS, respectively. An enrichment factor of 200 and RSD of ±1.19–1.49 % for five successive determinations of 25 μg?L^?1 were achieved. The column preconcentration was successfully applied to the analysis of tap water and underground water samples.     

离子色谱法-抑制型电导检测城市污水中的高氯酸根

利用离子色谱法-抑制型电导检测了城市污水中的持久污染物高氯酸根,以IonPac AS20高容量强亲水阴离子交换柱分离,NaOH流动相等度淋洗,高氯酸根在12min内出峰。高氯酸根在0.01~50 mg/L内具有良好的线性,相关系数为0.9998,50μl进样时检出限可达到3μg/L。方法可用于多种城市污水中高氯酸根的监测,样品测定的标准相对偏差在0.60%~0.94%之间,加标回收率在97.3%~105.8%之间,具有较好的准确性和重现性。