溶剂浮选-HPLC法测定茵陈水煎液中滨蒿内酯

采用溶剂浮选分离富集-HPLC测定了茵陈水煎液中的滨蒿内酯. 考察了浮选溶剂、N2气流速、试液pH值、浮选时间及电解质NaCl等因素对浮选效果的影响,确定了最佳浮选条件. 在最佳条件下加标回收率为92.31%～99.97%,RSD=3.20%,可满足实际样品的分析.     

溶剂浮选法分离富集茶叶中茶多酚的研究

采用溶剂浮选法分离富集了茶叶中的茶多酚。考察了浮选溶剂、氮气流速、试液pH及浮选时间等因素对浮选效率的影响,优选出最佳浮选条件;对最佳条件下的浮选效果进行了评价,并与溶剂萃取法进行了比对,前者明显优于后者。     

溶剂浮选法分离富集葛根中大豆甙元的研究

采用溶剂浮选法分离富集葛根中的大豆甙元。考察了浮选溶剂、氮气流速、试液pH、浮选时间及电解质（KC1）等因素对浮选效率的影响,优选出最佳浮选条件;对最佳条件下的浮选效果进行了评价,并与溶剂萃取法进行了对照,前者明显优于后者。     

穿心莲内酯的溶剂浮选

应用溶剂浮选法对穿心莲乙醇提取液中的穿心莲内酯进行分离富集,优化了穿心莲内酯的浮选条件.实验表明:浮选溶剂为乙酸乙酯,水相与有机相体积比为2: 1,加入水相体积4%的乙醇,溶液pH 7,氮气流速200 mL/min,浮选时间40 min为最佳浮选条件.在最佳实验条件下,穿心莲内酯平均收率为94.1%; RSD为1.1%,平均标准加入回收率95.1%; 富集倍数为9.7倍.溶剂浮选法分离穿心莲内酯不仅能得到满意的回收率和富集倍数,并能有效地除去水溶性杂质,提高目标物纯度.与溶剂萃取法相比, 溶剂浮选法能节约有机溶剂和操作时间.     

溶剂浮选-紫外分光光度法测定厚朴中总厚朴酚

建立了一种测定厚朴中总厚朴酚的新方法,即采用溶剂浮选法分离富集厚朴中的总厚朴酚,用紫外分光光度法测定其含量。考察了浮选溶剂、试液pH、氮气流速、浮选时间及电解质NaCl等因素对浮选效果的影响,优选出最佳浮选条件。采用所述方法对不同产地厚朴样品中总厚朴酚含量进行测定,样品加标回收率为94.9%-100.8%,RSD为2.8-4.1%。     

溶剂浮选分离富集麻黄草中有效成分

采用溶剂浮选法分离富集麻黄草中的有效成分。考察了浮选溶剂、氮气流速、试液pH、浮选时间及电解质NaCl等因素对浮选效率的影响,优选出最佳浮选条件;对最佳条件下的浮选结果进行了评价,并与溶剂萃取法进行了对照;对麻黄草有效成分的浮选过程进行了初步探讨,浮选过程符合一级动力学方程。     

溶剂浮选法分离富集淫羊霍提取液中淫羊霍苷

应用溶剂浮选法对淫羊霍提取液中的淫羊霍苷进行分离富集,并用高效液相色谱法测定淫羊霍苷的含量。考察了浮选溶剂的用量、氮气流速、浮选液pH值、浮选时间和电解质NaCl浓度对浮选效率的影响,并与泡沫浮选法以及溶剂萃取法进行了比较。结果表明溶剂浮选法分离富集的效果最好,泡沫浮选法次之,溶剂萃取法最差,富集倍数分别为6.4、5.9和1.4倍,收率分别为64.4%、58.8%和28.4%。     

溶剂浮选-气相色谱/质谱法测定蔬菜中氨基甲酸酯类农药残留

建立了一种有效分离富集并榆测蔬菜中氨基甲酸酯类农药残留的方法,即采用溶剂浮选法(SS)对蔬菜中的氨基甲酸酯类农药残留进行分离富集.然后用气相色谱,质谱(GC/MS)进行检测.考察了浮选溶剂、试液pH、通气速度及浮选时间等因索对浮选效果的影响,得剑了优化浮选条件 对此条件下的浮选产物进行气相色谱/质谱检测,回收率为81.6%～97.8%,RSD为1.39%～2.65%,定量限(LOQ)为0.39-6.17 pg/kg.     

溶剂浮选-高效液相色谱法同时测定水体中痕量4-硝基甲苯、二苯甲酮和正丁苯

建立了一种同时测定水体中痕量4-硝基甲苯、二苯甲酮和正丁苯含量的新方法, 即采用溶剂浮选法分离富集水体中的痕量 4-硝基甲苯、二苯甲酮和正丁苯类环境激素, 用高效液相色谱法测定其含量. 考察了浮选溶剂、试液 pH、氮气流速、浮选时间等因素对浮选效果的影响, 优选出最佳浮选条件. 采用所述方法对石化地区水体中 4-硝基甲苯、二苯甲酮和正丁苯类环境激素进行测定, 样品加标回收率为92.7%～114.3%, RSD为4.8%～8.4%.     

离子液体双水相溶剂浮选法分离/富集桑黄黄酮类成分

将亲水性离子液体氯化-1-丁基-3-甲基咪唑([C4mim]Cl)和K2HPO4形成的双水相体系与溶剂浮选结合,建立了分离/富集桑黄中总黄酮类成分的方法。考察了分相盐的种类和用量、样品量、溶液pH值、浮选时间和氮气流速对浮选效果的影响,并与双水相萃取进行比较。当浮选分相盐K2HPO4的质量浓度为50%、溶液pH=9.53、离子液体的用量为3 mL、浮选时间为50 min、氮气流速为30 mL/min时,浮选效率最佳,达到85.31%,富集倍数为8.59。离子液体双水相溶剂浮选法浮选效率高,富集倍数大,为中草药有效成分分离/富集提供了新方法。     

Determination of pyrethroid pesticide residues in vegetables by solvent sublation followed by high-performance liquid chromatography

A novel method is developed for separating and enriching pyrethroid pesticides from vegetables by solvent sublation, and determination of the pyrethroids is performed by high-performance liquid chromatography (HPLC). The effects of organic solvent, pH of the solution, nitrogen flow rate, and sublation time on the sublation efficiency of pyrethroids are investigated in detail, and the optimal conditions of the solvent sublation are selected. The floated product of vegetables in the optimal conditions is determined by HPLC. The limit of detection values range from 1.4 microg/kg (for bifenthrin) to 4.2 microg/kg (for fenpropathin). The recoveries of spiked vegetable samples are from 85.7% to 110.4%, and relative standard deviation values are from 1.70% to 6.19%. The results are satisfactory.     

Separation, concentration and determination of chloramphenicol in environment and food using an ionic liquid/salt aqueous two-phase flotation system coupled with high-performance liquid chromatography

Ionic liquid–salt aqueous two-phase flotation (ILATPF) is a novel, green, non-toxic and sensitive samples pretreatment technique. ILATPF coupled with high-performance liquid chromatography (HPLC) was developed for the analysis of chloramphenicol, which combines ionic liquid aqueous two-phase system (ILATPS) based on imidazolium ionic liquid (1-butyl-3-methylimidazolium chloride, [C₄mim]Cl) and inorganic salt (K₂HPO₄) with solvent sublation. In ILATPF systems, phase behaviors of the ILATPF were studied for different types of ionic liquids and salts. The sublation efficiency of chloramphenicol in [C₄mim]Cl–K₂HPO₄ ILATPF was influenced by the types of salts, concentration of K₂HPO₄ in aqueous solution, solution pH, nitrogen flow rate, sublation time and the amount of [C₄mim]Cl. Under the optimum conditions, the average sublation efficiency is up to 98.5%. The mechanism of ILATPF contains two principal processes. One is the mechanism of IL–salt ILATPS formation, the other is solvent sublation. This method was practical when applied to the analysis of chloramphenicol in lake water, feed water, milk, and honey samples with the linear range of 0.5–500 ng mL⁻¹. The method yielded limit of detection (LOD) of 0.1 ng mL⁻¹ and limit of quantification (LOQ) of 0.3 ng mL⁻¹. The recovery of CAP was 97.1–101.9% from aqueous samples of environmental and food samples by the proposed method. Compared with liquid–liquid extraction, solvent sublation and ionic liquid aqueous two-phase extraction, ILATPF can not only separate and concentrate chloramphenicol with high sublation efficiency, but also efficiently reduce the wastage of IL. This novel technique is much simpler and more environmentally friendly and is suggested to have important applications for the concentration and separation of other small biomolecules.     

Application of solvent sublation for the determination of organophosphorous pesticides in vegetables by gas chromatography with a flame photometric detector.

An effective method for separating and enriching organophosphorous pesticides (OPPs) from vegetables by solvent sublation and the OPPs determination by gas chromatography with flame photometric detector (GC-FPD) has been developed. The effects of organic solvent, nitrogen flow rate, pH of the solution, sublation time etc. on the sublation efficiency of OPPs were investigated in detail, and the optimal conditions of solvent sublation were selected. The floated product of vegetables in the optimal conditions was determined by GC-FPD. The limits of detection (LODs) ranged from 1.2 microg kg-1 (for dimethoate) to 3.5 microg kg-1 (for chlorpyrifos). The recoveries of spiked vegetable samples were from 81.3 to 98.9%, and RSD values were from 0.46 to 4.83%. The results show that this method is simple, sensitive and rapid.     

Highly sensitive determination and validation of gabapentin in pharmaceutical preparations by HPLC with 4-fluoro-7-nitrobenzofurazan derivatization and fluorescence detection

A sensitive HPLC method with pre-column fluorescence derivatization using 4-Fluoro-7-Nitrobenzofurazan (NBD-F) has been developed for the determination of gabapentin in pharmaceutical preparations. The method is based on the derivatization of gabapentin with (NBD-F) in borate buffer of pH 9.5 to yield a yellow, fluorescent product. The HPLC separation was achieved on a Inertsil C(18) column (250 mm × 4.6 mm) using a mobile phase of methanol water (80:20, v/v) solvent system at 1.2 mL/min flow rate. Mexiletine was used as the internal standard. The fluorometric detector was operated at 458 nm (excitation) and 521 nm (emission). The assay was linear over the concentration range of 5 50 ng/mL. The method was validated for specificity, linearity, limit of detection, limit of quantification, precision, accuracy, robustness. Moreover, the method was found to be sensitive with a low limit of detection (0.85 ng/mL) and limit of quantitation (2.55 ng/mL). The results of the developed procedure for gabapentin content in capsules were compared with those by the official method (USP 32). Statistical analysis by t- and F-tests, showed no significant difference at 95 confidence level between the two proposed methods.     

液相微萃取-高效液相色谱法快速测定唾液中尼古丁含量

建立了一种以液相微萃取为样品前处理技术,结合高效液相色谱快速、有效测定唾液中尼古丁含量的方法。确定了以磷酸三丁酯为有机溶剂、2 mL 0.05 mol/L KOH调节2 mL样品溶液为给出相,10 mmol/LKH2PO4(pH=3.0)为接收相;搅拌速率为500 r/min,萃取时间为17 min的尼古丁优化萃取条件。方法的线性范围0.1-50 mg/L,相关系数r2=0.9996;检出限为0.05 mg/L(S/N=3);相对标准偏差<5%(n=5);相对回收率为96.3%-102.2%。实验证明该法可用于唾液等生物体液中碱性物质的测定。