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《理化检验(化学分册)》2016,(7)
采用搅拌棒吸附萃取结合液相色谱-串联质谱法测定微山湖水中的马拉硫磷、三唑磷、喹硫磷、伏杀硫磷等4种有机磷农药残留。对影响有机磷农药残留吸附萃取效率的萃取涂层、样品溶液的酸度、振荡速率、萃取时间、溶液的离子强度、解吸液、解吸时间和解吸模式等因素进行了优化,确定了最佳吸附萃取条件。样品经搅拌棒萃取、解吸后,采用ZORBAX Eclipse Plus C_(18)色谱柱分离。在多反应监测模式下检测,外标法定量。4种有机磷农药的质量浓度在一定范围内与峰面积呈线性关系,检出限(3S/N)在0.16~0.73μg·kg~(-1)之间。加标回收率在72.3%~107%之间,测定值的相对标准偏差(n=6)在7.8%~11%之间。 相似文献
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基于离子液体的液相微萃取技术对纺织品中22种致癌芳香胺的测定 总被引:4,自引:1,他引:3
采用以离子液体为萃取剂的液相微萃取,对纺织品检测国家标准方法(GB/T 17592-2006)中纺织品样品前处理方法进行了改进,建立了纺织品中源于偶氮染料的芳香胺的提取新方法.比较了直接浸入式微萃取和溶剂棒微萃取模式的萃取效果,确定以溶剂棒微萃取为微萃取模式.并优化了液相微萃取条件:以正辛醇为有机萃取溶剂,离子液体为接收相,给出相pH值为10并添加饱和NaCl溶液,搅拌速率为1 000 r/min,萃取时间为40 min.参照纺织品检测国家标准方法,采用高效液相色谱法对所公布的22种致癌芳香胺进行了定性、定量测定.结果表明,该方法的线性范围宽,相关系数r>0.995 1,检出限(S/N=3)为0.01 ~2.13 μg/L,相对标准偏差小于4.5%( n=8);回收率为82% ~94%,8种芳香胺的富集倍数为5.7 ~270.0.与纺织品检测国家标准方法相比,该方法简单、快速,并显示了较好的富集效果和高的回收率. 相似文献
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白菜中有机磷农药的电纺纳米纤维固相萃取-高效液相色谱法测定 总被引:2,自引:0,他引:2
以聚苯乙烯电纺纳米纤维为固相萃取介质填装固相萃取小柱,对白菜中的5种有机磷农药(杀扑磷、马拉硫磷、辛硫磷、丙溴磷、毒死蜱)富集净化,甲醇洗脱吸附在小柱上的农药后,用高效液相色谱-紫外检测器进行检测.对萃取次数、白菜样品提取液、洗脱液、pH值进行了优化,杀扑磷、马拉硫磷、辛硫磷、丙溴磷、毒死蜱在固相萃取小柱上的最大吸附量分别为2.9、3.5、5.6、3.7、7.8 mg/g,5种有机磷农药的平均加标回收率为68% ~97%,相对标准偏差为1.6% ~4.7%.测定喷洒5种农药后的白菜样品的萃取回收率为65% ~93%,相对标准偏差为1.6% ~4.0%,5种农药的检出限为0.02 ~0.1 mg/kg.该方法操作简单、价廉,能够用于白菜中有机磷农药的测定. 相似文献
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自动顶空衍生化固相微萃取法测定啤酒中的老化醛类化合物 总被引:3,自引:0,他引:3
采用邻-五氟苯甲基羟胺(PFBOA)衍生,顶空固相微萃取(HS-SPME)和气相色谱质谱(GC-MS)测定啤酒中2-甲基丁醛、3-甲基丁醛、反-2-壬烯醛等8种老化醛类化合物.顶空固相微萃取采用65 μm PDMS/DVB纤维,先用纤维吸附PFBOA溶液,再将纤维插入装有2 mL啤酒的20 mL顶空进样瓶的顶空中在60 ℃萃取60 min,衍生和萃取都在自动进样器中进行.采用GC-MS检测,特征离子为m/z 181.8种羰基化合物在0.2~500 μg/L范围内线性关系良好,相关系数在0.990以上.检测样品的相对标准偏差为1.0%~15.7%,回收率为88%~103%.同时研究并讨论了萃取纤维、萃取温度、萃取时间、样品体积等因素对醛类萃取量的影响.该方法可用于啤酒保鲜期研究和产品质量控制. 相似文献
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固相微萃取法在禁用偶氮染料检测中的应用初探 总被引:5,自引:1,他引:4
将固相微萃取技术应用于出口染色纺织品及皮革制品中禁用偶氮染料检验,偶染料经连二亚硫酸钠还原成芳胺后,用固相微萃取技术萃取富集后,用GC-MS分析。实验了萃取方式、萃取纤维、pH值、浓度、温度、萃取时间及色谱条件等因素对萃取与测定的影响。 相似文献
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以甲苯二异氰酸酯(TDI)中的-NCO基与纳米金属氧化物表面的羟基发生反应,得到改性纳米金属氧化物,并使其与肝素钠(Heparin)进行接枝反应生成肝素杂化材料,结合红外、热重、扫描电镜(SEM)等表征方法,确定纳米金属氧化物确实接枝到了肝素钠的表面。通过对体外凝血时间和复钙时间的测定,来初步研究肝素杂化材料的抗凝血性质。结果表明:肝素杂化材料的抗凝血时间和复钙时间均比肝素钠的要短,表明它的抗凝血性比肝素钠的抗凝血性要弱一些;但比纳米金属氧化物和空白组的抗凝血时间和复钙时间要长,说明肝素杂化材料的抗凝血性与其相比则有明显的提高。 相似文献
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利用L16(45)正交试验设计,考察了石墨炉原子吸收法测定大米中镉的灰化温度、灰化时间、原子化温度、原子化时间.确定了最佳灰化温度为450℃、灰化时间为15s、原子化温度为1750℃、原子化时间为4s等仪器的最佳参数. 相似文献
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Li S He S Zhong S Duan X Ye H Shi J Peng A Chen L 《Journal of chromatography. A》2011,1218(20):3124-3128
The elution-extrusion counter-current chromatography (EECCC) method was firstly developed by Berthod in 2003 and has been used in natural products separation in recent years. The advantages of this method have been well documented such as reducing the separation time and solvent consumption. In the EECCC method, the time point of the extrusion step is very important during the whole separation process as it directly affects the resolutions, separation time and solvent consumption. However, how to choose a suitable time point to perform the extrusion step without decreasing the resolution has not been studied yet. In the present study, a strategy for systematically calculating the time point for extrusion was developed in theory and five bioactive compounds from the extract of Dendrobium chrysototxum Lindl. were separated and compared using normal CCC and EECCC method. Our results demonstrated that the accurate time point to perform the extrusion could be calculated and reduced both separation time and solvent consumption without losing separation performance. Using this EECCC method, five bioactive compounds were separated and purified with high purity. The separation time and solvent consumption were decreased from 200 min to 100 min and 5-2.5L during the separation process while the resolutions were still acceptable. Finally, 63 mg, 48 mg, 97 mg, 162 mg and 43 mg of hydroxyl phenanthrenes and bibenzyls with the purity of 98.7%, 98.0%, 98.2%, 99.0% and 98.7%, respectively were isolated from 1.2 g crude extract of D. chrysototxum Lindl. initially purified by column chromatography in one step separation. The purities of compounds were determined by HPLC. Their structures were identified by electrospray ionization-mass spectrometry (ESI-MS) and NMR. 相似文献
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利用微波相敏技术,获得了硫增感AgBrIT颗粒乳剂中自由光电子和束缚光电子时间衰减信号,分析了光电子衰减时间、电子陷阱效应、光电子寿命、有效陷阱深度及束缚电子转移时间与增感时间的关系,获得了最佳的增感时间、衰减时间、电子陷阱效应、光电子寿命、有效陷阱深度和转移时间数值. 相似文献
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《Liquid crystals》1997,22(3):297-300
The dynamics of the field-induced one-dimensional twist deformation in weakly anchored nematic layers was investigated by means of numerical simulation. The rise time constants and the decay time constants, characteristic for the onset and for the decay of the deformation, respectively, were determined. The time of delay, which had passed before the decay started, was revealed in the case of finite anchoring. For weaker anchoring, the time of delay and the decay time constant were longer. Surprisingly, the onset of the deformation was slower when the anchoring was weaker, provided that the ratio of the actual field strength to the threshold field strength was fixed. 相似文献
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聚乙烯表面接枝聚合改性及抗凝血性的研究 总被引:3,自引:1,他引:2
聚乙烯(PE)膜经Ar等离子体预处理,无光引发剂紫外光照接枝甲基丙烯酸缩水甘油酯(GMA),然后进行肝素化处理,以改善PE的抗凝血性能。用正交实验确定接枝反应的最优条件。通过X-射线光电子能谱(XPS)、衰减全反射红外光谱(ATR-FTIR)、扫描电子显微镜(SEM)和接触角测定PE膜接枝GMA前后表面性能和表面形貌。用复钙时间、凝血酶原时间、部分凝血活酶时间、凝血酶时间和血小板粘附实验对其抗凝血性能进行评价,结果表明,被修饰PE膜的抗凝血性能显著提高。 相似文献