固相萃取-气相色谱/质谱联用法测定卷烟主流烟气中的香兰素和乙基香兰素

采用固相萃取-气相色谱/质谱联用技术,建立了一种同时测定卷烟主流烟气中香兰素和乙基香兰素的方法。方法优化了萃取条件,考察了萃取溶剂、萃取时间对检测结果的影响。通过硅藻土固相萃取柱净化并浓缩后,选取DB-HeavyWAX毛细管柱进行目标物分离,以香兰素-d3作为内标,对香兰素和乙基香兰素进行定量分析。结果表明,香兰素和乙基香兰素在浓度0.2~20.0 mg/L范围内具有良好的线性关系,其检出限分别为9.1 ng/支和6.5 ng/支,回收率均在96.3%~107.7%之间。     

离子交换固相萃取高效液相色谱联用法检测河豚鱼中的河豚毒素

优化建立了采用混合模式阳离子交换固相萃取柱代替传统的C18固相萃取柱进行前处理,联用高效液相色谱检测河豚鱼中河豚毒素的方法.样品经合1％乙酸的乙腈甲醇(3:1,V:V)溶液提取,混合模式阳离子交换固相萃取柱(MCX)净化,5％氨水/甲醇溶液洗脱,采用高效液相色谱-二极管阵列检测器(HPLC-PAD)测定,外标法定量.河...     

高效液相色谱法同时测定婴幼儿配方乳粉中5种游离核苷酸

建立了婴幼儿配方乳粉中5种游离核苷酸的准确测定方法。采用等电点沉淀蛋白,强阴离子交换固相萃取柱净化,Atlantis T3色谱柱分离,二极管阵列检测器检测,外标法定量。结果表明:5种核苷酸在0.1~100μg/m L范围内线性关系良好(r≥0.999),平均回收率为95.2%~103%,相对标准偏差均小于4.5%。方法可为企业质量控制和政府监管提供有力的技术支撑。     

混合型固相萃取柱净化-气相色谱-质谱法测定婴幼儿配方奶粉中的三聚氰酸

建立了一种混合型固相萃取柱净化-气相色谱-质谱法(GC-MS)测定婴幼儿配方奶粉中三聚氰酸的方法。在84 ℃条件下,用0.5%乙酸水溶液提取样品中的三聚氰酸,离心,滤液经Carb/C18混合型固相萃取柱净化,氮气吹干,硅烷化衍生,GC-MS测定,选择离子监测模式,外标法定量。在0.01～2 mg/L内线性关系良好(r＞0.99),在0.25～2.5 mg/kg的添加水平范围内,平均回收率为80%～103%,相对标准偏差(RSD)为7.7%～14.5%,三聚氰酸的检出限(LOD)为0.10 mg/kg,定量限(LOQ)为0.25 mg/kg。该方法快速、灵敏、准确、专一、耐用,适合婴幼儿配方奶粉中三聚氰酸的确证和定量测定。     

液相色谱-串联质谱法同时测定婴幼儿配方奶粉中4种香料

采用液相色谱-串联质谱建立了同时测定婴幼儿配方奶粉中香兰素、甲基香兰素、乙基香兰素和香豆素4种香料的分析方法。样品用甲醇-水(1∶1)超声提取,提取液经离心过滤、HLB固相萃取柱净化后,采用Waters Xselect HSS T3色谱柱(2.1 mm×150 mm,3.5μm)分离,以0.1%甲酸溶液-乙腈作为流动相进行梯度洗脱,目标分析物在多反应监测(MRM)模式下以保留时间和离子对(母离子和两个碎片离子)进行定性分析,内标法定量。7 min内即可完成4种化合物的分离分析。在优化实验条件下,香兰素在1.0~50 ng·mL-1范围内呈良好的线性关系,另外3种化合物的线性范围为0.5~50 ng·mL-1,相关系数均不低于0.9993,方法定量下限为10.0μg·kg-1(香兰素)和5.0μg·kg-1(甲基香兰素、乙基香兰素和香豆素),在低、中、高3个加标水平下,4种化合物的平均回收率为85.2%~107.4%,相对标准偏差(RSD)不大于5.7%。方法简便、有效、灵敏,为评价奶粉样品质量提供了新的检测方法。     

固相萃取-液相色谱法测定婴幼儿配方乳粉中的游离核苷酸

该文建立了婴幼儿配方乳粉中5种游离核苷酸的检测方法。婴幼儿配方乳粉经乙二胺四乙酸二钠和氯化钠溶液提取,强阴离子（SAX）固相萃取柱净化,通过反相Atlantis T₃色谱柱分离,二极管阵列检测器检测,外标法定量。结果表明：方法抗干扰能力强、准确度高,尤其对羊奶粉净化效果好、分离度高。5种游离核苷酸在0.5~10 mg/L范围内线性关系良好（r≥0.999）;添加水平在0.05~0.50 g/kg时,回收率为91.1%~112%,相对标准偏差为2.3%~4.7%;检出限为0.0010~0.0015 g/kg,定量限为0.0030~0.0045 g/kg。对乳粉质控样品进行检测,结果与中位值比较的偏差在10%以内。该方法可为监管部门提供技术支持,为乳品行业健康发展提供保障。     

牛奶样品中新霉素残留量的离子色谱法测定

建立了阴离子交换色谱-脉冲安培检测分析牛奶中新霉素残留量的方法.实验采用三氯乙酸沉淀蛋白,弱阳离子交换固相萃取柱富集净化,处理牛奶样品,并考察了三氯乙酸浓度、样品过柱速度以及洗脱剂浓度等因素对牛奶中新霉素测定结果的影响.牛奶中新霉素的回收率在50.3%～76.9%范围内,基底加标工作曲线的相关系数为0.9949(n=6),线性范围为10.0～160.0ng/mL.所建立的方法可满足牛奶中低新霉素残留量的检测需要.     

液相色谱-质谱法测定食品中甜蜜素

食品样品与水混合后超声振荡萃取使甜蜜素进入水溶液中,再用阴离子交换固相萃取柱净化.用乙酸(1 4)淋洗,所得流出液供液相色谱-质谱定量测定.峰高及甜蜜素的质量浓度在0.01～50.0 mg·L-1叫范围内呈线性关系,相关系数为0.999 8.其检出限(S/N=3:1)为20 pg,测得方法的回收率在94.1%～99.1%之间.     

ASE-SPE-HPLC测定蔬菜中7种农药的残留量

建立了快速溶剂萃取-固相萃取柱净化-高效液相色谱法( ASE-SPE-HPLC)同时测定蔬菜中痕量双甲脒、久效磷、水胺硫磷、多效唑、克线磷、2,4-D和噻嗪酮7种农药残留量的方法.采用快速溶剂萃取仪提取样品,提取液经固相萃取柱净化后,以70％甲醇+10％乙腈+20％水为流动相,以保留时间定性确证,峰面积外标法进行定量....     

GC-MS/MS法测定沉积物和生物样品中邻苯二甲酸酯

采用固相萃取(SPE)和QuEChERS技术结合气相色谱-串联质谱(GC-MS/MS)技术,建立了养殖海域沉积物和生物样品中16种邻苯二甲酸酯(PAEs)定量分析方法.沉积物样品以二氯甲烷为提取溶剂,经PSA-Silica固相萃取柱净化,生物样品以乙腈为提取溶剂,经150.0 mg N-丙基乙二胺(PSA)、150.0...     

Optimization of enzymatic process for vanillin extraction using response surface methodology

Vanillin was extracted from vanilla beans using pretreatment with cellulase to produce enzymatic hydrolysis, and response surface methodology (RSM) was applied to optimize the processing parameters of this extraction. The effects of heating time, enzyme quantity and temperature on enzymatic extraction of vanillin were evaluated. Extraction yield (mg/g) was used as the response value. The results revealed that the increase in heating time and the increase in enzyme quantity (within certain ranges) were associated with an enhancement of extraction yield, and that the optimal conditions for vanillin extraction were: Heating time 6 h, temperature 60 °C and enzyme quantity 33.5 mL. Calculated from the final polynomial functions, the optimal response of vanillin extraction yield was 7.62 mg/g. The predicted results for optimal reaction conditions were in good agreement with experimental values.     

Microwave- and ultrasound-assisted extraction of vanillin and its quantification by high-performance liquid chromatography in Vanilla planifolia

Microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE) and conventional extraction of vanillin and its quantification by HPLC in pods of Vanilla planifolia is described. A range of nonpolar to polar solvents were used for the extraction of vanillin employing MAE, UAE and conventional methods. Various extraction parameters such as nature of the solvent, solvent volume, time of irradiation, microwave and ultrasound energy inputs were optimized. HPLC was performed on RP ODS column (4.6 mm ID x 250 mm, 5 microm, Waters), a photodiode array detector (Waters 2996) using gradient solvent system of ACN and ortho-phosphoric acid in water (0.001:99.999 v/v) at 25 degrees C. Regression equation revealed a linear relationship (r2 > 0.9998) between the mass of vanillin injected and the peak areas. The detection limit (S/N = 3) and limit of quantification (S/N = 10) were 0.65 and 1.2 microg/g, respectively. Recovery was achieved in the range 98.5-99.6% for vanillin. Maximum yield of vanilla extract (29.81, 29.068 and 14.31% by conventional extraction, MAE and UAE, respectively) was found in a mixture of ethanol/water (40:60 v/v). Dehydrated ethanolic extract showed the highest amount of vanillin (1.8, 1.25 and 0.99% by MAE, conventional extraction and UAE, respectively).     

Rapid method for the determination of coumarin, vanillin, and ethyl vanillin in vanilla extract by reversed-phase liquid chromatography with ultraviolet detection

A method is described for determining coumarin, vanillin, and ethyl vanillin in vanilla extract products. A product is diluted one-thousand-fold and then analyzed by reversed-phase liquid chromatography using a C18 column and a mobile phase consisting of 55% acetonitrile-45% aqueous acetic acid (1%) solution at a flow rate of 1.0 mL/min. Peaks are detected with a UV detector set at 275 nm. Vanilla extracts were spiked with 250, 500, and 1000 microg/g each of coumarin, vanillin, and ethyl vanillin. Recoveries averaged 97.4, 97.8, and 99.8% for coumarin, vanillin, and ethyl vanillin, respectively, with coefficient of variation values of 1.8, 1.3, and 1.3%, respectively. No significant difference was observed among the 3 spiking levels. A survey of 23 domestic and imported vanilla extract products was conducted using the method. None of the samples contained coumarin. The surveyed samples contained between 0.4 to 13.1 and 0.4 to 2.2 mg/g vanillin and ethyl vanillin, respectively.     

Supported liquid membranes for the determination of vanillin in food samples with amperometric detection

A supported liquid membrane system has been developed for the extraction of vanillin from food samples. A porous PTFE membrane is impregnated with an organic solvent, which forms a barrier between two aqueous phases. The analyte is extracted from a donor phase into the hydrophobic membrane and then back extracted into a second aqueous solution, the acceptor. The determination (100–1400 μg ml⁻¹ vanillin) was performed using a PVC-graphite composite electrode versus Ag/AgCl/3MKCl at +0.850 V placed in a wall-jet flow cell as amperometric detector. The solid sample is directly placed in the membrane unit without any treatment, and the analyte was extracted from the sample, passes through the membrane and conduced to the flow cell by the acceptor stream. The limit of detection (3σ) was 44 μg ml⁻¹. The method was applied to the determination of vanillin (9–606 μg g⁻¹) in food samples.     

Focused microwaves-assisted extraction and simultaneous spectrophotometric determination of vanillin and p-hydroxybenzaldehyde from vanilla fragans

A new method to quick extraction of vanillin and p-hydroxybenzaldheyde (PHB) of vanilla beans from vanilla fragans is proposed. Samples were irradiated with microwaves energy to accelerate the extraction process and photometric monitoring was performed at 348 and 329 nm (vanillin and PHB, respectively). The simultaneous determination of vanillin and PHB from extracts was performed using the Vierordt's method, which showed a precision, expressed as relative standard deviation, smaller 2.5% for both analytes. Conditions such as microwaves irradiation power, number of irradiation and non-irradiation cycles, irradiation time and ethanol concentration were optimized by means of multivariate screening that showed that irradiation power and number of irradiation cycles are the most significant condition in the vanilla extraction process. The focused microwave-assisted extraction (FMAE) was applied to commercial (dried vanilla beans from fresh green vanilla beans), lyophilised and dried (commercial vanilla dried at 135 °C in oven) vanilla beans samples. The results showed that the extraction of vanillin and PHB in the commercial vanilla samples were higher than in dried and lyophilised samples. With the proposed FMAE a decrease in the extraction time of 62 times and an increase in the vanillin and PHB concentrations between 40 and 50% with respect to the official Mexican extraction method, were obtained.     

Synthesis of the water-compatible p-acetaminophen resin and its adsorption performances for vanillin in aqueous solution

A novel p-acetaminophen resin(named as GQ-1) was synthesized with chloromethylated polystyrene and p-acetaminophen.It can be used without any wetting process.The objective of this work was to study the adsorption performances for vanillin onto GQ-1 with two kinds of the hydrogen bond site of acetamino group and hydroxyl group.The results showed that the adsorption property of vanillin onto GQ-1 was superior to XAD-4,H103,NDA150,and NDA88.The adsorption capacity of vanillin onto GQ-1 is not greatly discrepant until the solution pH is higher than 5.31.The saturated adsorption quantity of vanillin was up to 141.32 mg/mL(wet resin) according to the dynamic adsorption and desorption experiments at 293 K.The resin could be regenerated by 7 BV ethanol.     

Development of a LC-ESI/MS/MS assay for the quantification of vanillin using a simple off-line dansyl chloride derivatization reaction to enhance signal intensity

Vanillin is responsible for producing the familiar smell of vanilla. Vanillin has many similarities with other flavor phenolic compounds and could potentially show similar pharmacological activity. A previously published analytical method was adapted, developed and tested. Vanillin was extracted from rat plasma using protein precipitation with acetone. Prior to LC-ESI/MS/MS analysis, an aliquot of the supernatant was used to proceed to the derivatization of vanillin and the internal standard with dansyl chloride to enhance signal intensity in positive electrospray mode. The chromatography was performed on a 100 x 2.1 mm C8 column and an isocratic mobile phase composed of 75:25 acetonitrile:0.5% formic acid in water with a flow rate fixed at 500 microL/min. A linear (weighted 1/concentration) relationship was used to perform the calibration over an analytical range of 10-10,000 ng/mL. The intra-batch precision and accuracy at the limit of quantitation (10 ng/mL), medium (500 ng/mL) and high (10,000 ng/mL) concentrations were 10.7, 7.0 and 7.2% and 103.5, 108.0 and 100.1%, respectively. The observed recovery was greater than 87% and no significant ionization suppression or matrix effect was observed. This LC-ESI/MS/MS method for the determination of vanillin in rat plasma provided results within generally accepted criteria used for bioanalytical assay.     

毛细管区带电泳法同时分离测定香兰素和邻位香兰素异构体

建立了同时测定香兰素和其异构体邻位香兰素的毛细管区带电泳法(CZE)。考察了缓冲溶液的种类、浓度和pH以及分离电压等因素对分离结果的影响。在缓冲溶液为50 mmol/L硼砂-150 mmol/L磷酸氢二钠(pH 7.5)、分离电压15 kV的优化条件下,6 min内即可实现分离。香兰素和邻位香兰素在10～240 mg/L范围内线性关系良好,相关系数分别为0.9999和0.9997;方法的检出限均为1.0 mg/L (信噪比为3);样品的加标回收率为99.4%～101.2%,相对标准偏差为0.19%～0.73%。该方法操作简单、快速,已应用于实际样品的分析,并获得了令人满意的结果。     

Chemiluminometric determination of vanillin in commercial vanillin products

Vanillin, ethylvanillin and 4-hydroxy-3-methoxy-benzylalcohol have been found to chemiluminesce by the action of potassium permanganate in sulphuric or polyphosphoric acid media. Both acid media have been compared and sulphuric acid allows the sensitive determination of 0.15-10.0, 0.010-1.0 and 0.0030-0.30 μg mL⁻¹ of vanillin, ethylvanillin and 4-hydroxy-3-methoxy-benzylalcohol with limits of detection equal to 0.045, 0.0030 and 0.00090 μg mL⁻¹, respectively. Recoveries of vanillin from commercial vanillin products are within the range of 95-109%. Comparison with results from the official method shows differences within the range of 0.5-3.0%. The chemiluminogenic reaction mechanism is also discussed.