气相色谱法检测氟节胺在葡萄和土壤中的残留

[目的]建立氟节胺在葡萄和土壤中的残留分析方法。[方法]样品经乙腈提取,N-丙基乙二胺(PSA)吸附剂和十八烷基键合硅胶(C18)吸附剂分散固相萃取净化,气相色谱-电子捕获检测器(μECD)分析,外标法定量。[结果]氟节胺最小检出量为3.0×10~(-11)g,最低检测质量分数为0.005 mg/kg。氟节胺的添加质量分数为0.01~0.50 mg/kg,在葡萄和土壤中的添加回收率分别为77.42%~104.40%和76.67%~104.56%,相对标准偏差(RSD,n=5)分别为4.68%~6.54%和5.92%~8.40%。[结论]方法简便、快速、精密度好,适合葡萄和土壤中氟节胺残留量的测定。     

新农药氯溴虫腈在甘蓝和土壤中的残留检测方法

[目的]建立甘蓝和土壤中氯溴虫腈残留的检测分析法,为其合理使用准则的制定提供参考。[方法]土壤样品经乙腈提取、二氯甲烷萃取,甘蓝样品经乙腈提取、盐析作用,再用装有无水硫酸钠和弗罗里硅土-活性炭混合物(质量比50∶1)的层析柱净化,采用HP-1毛细管柱和带电子捕获检测器的气相色谱仪定量测定甘蓝和土壤中的氯溴虫腈残留量。[结果]在有效成分质量浓度0.01~10 mg/L范围内氯溴虫腈峰面积与进样质量浓度呈现出良好的线性关系,R2=0.999 5;在添加质量分数水平0.01~1.0 mg/kg范围内,甘蓝和土壤中氯溴虫腈的平均回收率为96.0%~102.4%,相对标准偏差为3.4%~8.1%;方法最小检出量(LOD)为2×10-11 g,最低检测质量分数(LOQ)为0.01 mg/kg。[结论]该方法简便、快速、准确度高、精密度好,符合农药残留分析的要求,适用于甘蓝和土壤中氯溴虫腈的残留分析检测。     

固相萃取-超高效液相色谱-串联质谱法测定普洱茶中氟虫腈及其类似物残留

[目的]采用TPT固相萃取柱,对普洱茶中的氟虫腈及其类似物残留进行提取和净化,利用超高效液相色谱-串联质谱法进行定性和定量分析。[方法]普洱茶样品经过水润湿后,采用乙腈作为提取溶剂,提取液经TPT固相萃取柱净化后进样分析,采用负离子多反应监测(MRM)模式,外标法定量。[结果]氟虫腈及其类似物在0.05~5μg/L范围内线性关系良好,经过TPT固相萃取柱的净化后,氟虫腈及其类似物检出限都为0.003μg/kg,在0.05μg/kg添加质量分数下平均回收率范围为93.4%~97.1%,相对标准偏差范围为5.5%~7.1%。[结论]该方法简便、灵敏度高,能够有效去除普洱茶中的干扰物质,适于普洱茶中氟虫腈及其类似物的测定。     

氟环唑在水稻田中的残留消解动态研究

采用气相色谱-电子捕获检测器(GC-ECD)测定了氟环唑在水稻植株、土壤和田水样品中的消解动态。样品前处理均采用乙腈作提取剂,C18和Carb为分散剂进行净化,并用GC-ECD进行检测。当氟环唑在水稻植株、土壤、田水中的添加浓度为0.05~1.0 mg/kg时,其回收率为73.8%~103.2%,相对标准偏差(RSD)为2.7%~8.5%;氟环唑的最小检出量为1.0×10-11 g,在水稻植株、土壤和田水中的最低检测浓度为0.05mg/kg。消解动态试验结果显示,氟环唑在水稻植株和田水中的半衰期分别为2.6~12.6 d,2.0~2.2 d。     

加速溶剂萃取-液相色谱柱后衍生荧光法测定农田土壤中10种氨基甲酸酯类农药残留

建立液相色谱柱后衍生荧光法测定农田土壤中10种氨基甲酸酯类农药残留的分析方法。土壤经二氯甲烷:甲醇(1:1)加速溶剂萃取,GCB/NH2柱净化,柱后衍生荧光法测定,外标法定量。通过比较超声提取、自动索氏提取、加速溶剂萃取3种提取方式,确定土壤中10种氨基甲酸酯类农药的检测方法。结果表明:10种氨基甲酸酯类农药含量在0.02~1.0 mg/L间呈良好的线性关系,相关系数r2均大于0.998。添加0.05~0.50 mg/L浓度,平均回收率在86.8%~96.4%,相对标准偏差(RSD)为2.2%~5.3%。     

免疫亲和层析净化高效液相色谱法测定澳洲坚果中黄曲霉毒素B_1

建立了一种测定澳洲坚果中黄曲霉毒素B1的免疫亲和层析净化高效液相色谱法。采用甲醇-水提取,提取液经过滤、水稀释、净化,甲醇洗脱溶解,柱后衍生液相色谱仪荧光检测器测定。实验结果表明,澳洲坚果中黄曲霉毒素B1的检出限为0.2μg/kg,在添加水平为5、10、20μg/kg的回收率实验中,平均回收率为81%~96%,相对标准偏差为0.8%~3.7%。     

气相色谱法测定玉米中高效氯氟氰菊酯残留

研究了高效氯氟氰菊酯在玉米植株、土壤和玉米籽粒中残留分析方法.植株中高效氯氟氰菊酯经丙酮高速匀浆提取后,用弗罗里硅土净化、浓缩、定容后,用带BECD检测器的气相色谱仪进行测定.土壤中的高效氯氟氰菊酯用丙酮超声提取后,用二氯甲烷萃取净化、浓缩、定容后进样.玉米籽粒中的高效氯氟氰菊酯经乙腈高速匀浆提取,用弗罗里硅土/氧化铝净化、浓缩、定容后进样.高效氯氟氰菊酯的最低检出最为1.0×10-12g,在植株、土壤和籽粒中的最低检出质量分数为0.001 mg/kg.平均回收率在74.5%～108.4%之间.变异系数为2.4%～11.5%,符合残留分析要求.     

甘蓝和土壤中三氟甲吡醚残留量的快速定性与定量

建立了甘蓝和土壤中三氟甲吡醚残留的快速定性与定量方法。样品采用乙腈提取,分散固相萃取法净化,液相色谱/质谱电喷雾电离源、正离子模式下进行多反应监测。结果表明,三氟甲吡醚添加量在0.05~1.0 mg/kg水平下,甘蓝和土壤中的回收率为82.1%~98.0%,相对标准偏差为1.8%~14.1%,满足三氟甲吡醚残留量的检测要求。     

10%噻唑啉WP在番茄和土壤中的残留分析研究

本文采用二氯甲烷提取,氟罗里硅土柱净化,高效液相色谱法检测定量,最小检知量1.5×10-10 g。当添加浓度为0.05~1.0 mgkg-1时,噻唑啉在番茄和土壤中的平均回收率分别为93.1%~113.1%和86.1%~106.5%,变异系数分别为2.47%~8.72%和1.36%~9.09%。     

固相萃取-高效液相色谱检测稻田土壤中五氟磺草胺的残留

[目的]在国内首次建立五氟磺草胺在稻田土壤中残留量的高效液相色谱(HPLC)定量检测分析方法。[方法]试验采用乙腈和水作为提取液,提取土壤中残留的五氟磺草胺,用固相萃取柱净化、浓缩、定容,进行高效液相色谱测定。[结果]五氟磺草胺的最小检出量(LOD)为1.0 ng,最低检测质量分数(LOQ值)为0.1 mg/kg。在添加质量分数为0.1~1.0 mg/kg时,平均回收率为82.90%~108.24%,相对标准偏差为2.040 7%~8.702 6%。[结论]该方法灵敏度、准确度、精密度符合农药残留分析的要求。     

ASE-GC/MS法测定塑料中5种氯烃类化合物

建立了加速溶剂萃取-气相色谱/质谱联用法(ASE-GC/MS)用于检测塑料中5种氯烃类化合物的含量,并比较了萃取方法、萃取溶剂及萃取温度对萃取效果的影响。结果表明:5种氯烃类化合物的质量浓度在1.0²5.0mg/L范围内分别与其对应的峰面积呈线性关系,测定下限(10倍信噪比)均为1.0 mg/kg;另外,在1.00、5.00、10.00 mg/kg 3个添加浓度水平下,5种氯烃类化合物的回收率在83.2%25.0mg/L范围内分别与其对应的峰面积呈线性关系,测定下限(10倍信噪比)均为1.0 mg/kg;另外,在1.00、5.00、10.00 mg/kg 3个添加浓度水平下,5种氯烃类化合物的回收率在83.2%¹01.2%之间,相对标准偏差(RSD)小于5%。该方法准确度高,精密度好,能够满足实际检测需求。     

煤焦油中酚类化合物的分离及其组成结构鉴定研究进展

酚类化合物的提取是实现煤焦油高附加值利用的有效途径之一,掌握煤焦油中酚类化合物的分布情况、结构特点有助于高效分离方法的开发。针对煤焦油中粗酚的提取及精制,本文综述了碱液抽提法、溶剂萃取法和新型分离方法3类粗酚提取方法的研究现状,介绍了粗酚精制的研究进展,并讨论了不同粗酚提取、精制方法之间的优势与不足。系统阐述了光谱法、色谱法及核磁共振法3大类酚类化合物组成结构鉴定方法。探讨了该领域技术的发展趋势,认为酚类的分析鉴定需将多种先进手段结合,多层次、全方位地分析其组成及结构;粗酚的提取可以加快环保高效萃取剂的优选,推动新型萃取法的应用进度;粗酚精制在重点开发间、对甲酚及混合二甲酚高效提纯工艺的同时,加强高级酚提取的研究力度。     

Determination of Phenolic Acids and Flavonoids in Taraxacum formosanum Kitam by Liquid Chromatography-Tandem Mass Spectrometry Coupled with a Post-Column Derivatization Technique

A liquid chromatography-tandem mass spectrometry method (LC-MS/MS) was developed for the determination of phenolic acids and flavonoids in a medicinal Chinese herb Taraxacum formosanum Kitam. Initially, both phenolic acids and flavonoids were extracted with 50% ethanol in a water-bath at 60 °C for 3 h and eventually separated into acidic fraction and neutral fraction by using a C(18) cartridge. A total of 29 compounds were separated within 68 min by employing a Gemini C(18) column and a gradient solvent system of 0.1% formic acid and acetonitrile at a flow rate of 1.0 mL/min. Based on the retention behavior as well as absorption and mass spectra, 19 phenolic acids and 10 flavonoids were identified and quantified in T. formosanum, with the former ranging from 14.1 μg/g to 10,870.4 μg/g, and the latter from 9.9 μg/g to 325.8 μg/g. For further identification of flavonoids, a post-column derivatization method involving shift reagents such as sodium acetate or aluminum chloride was used and the absorption spectral characteristics without or with shift reagents were compared. An internal standard syringic acid was used for quantitation of phenolic acids, whereas (±) naringenin was found suitable for quantitation of flavonoids. The developed LC-MS/MS method showed high reproducibility, as evident from the relative standard deviation (RSD) values for intra-day and inter-day variability being 1.0-6.8% and 2.0-7.7% for phenolic acids and 3.7-7.4% and 1.5-8.1% for flavonoids, respectively, and thus may be applied for simultaneous determination of phenolic acids and flavonoids in Chinese herb and nutraceuticals.     

Optimization of microwave-assisted extraction of bioactive compounds from pistachio (Pistacia vera L.) hull

ABSTRACT

Phenolic compounds were extracted from pistachio hull using microwave-assisted solvent extraction (MASE). The effects of four parameters, microwave power, extraction time, solvent to sample ratio, and ethanol concentration were evaluated. The extraction conditions were optimized by response surface methodology to enhance the total phenolic content (TPC). Optimal conditions were found as 140 W microwave power, 4.5 min extraction time, 19:1 (v/w) solvent to sample ratio, and 56% ethanol concentration to get maximum TPC (62.24 mg GAE/g dry hull). Also, MASE was compared with conventional solvent extraction (CSE) and MASE gave higher TPC, yield, and antioxidant activity.     

气相色谱法测定饮用水中的二氯乙酸、三氯乙酸

参照生活饮用水标准检验方法中的液液萃取、酸化甲醇衍生化技术,采用气相色谱技术测定生活饮用水中的二氯乙酸和三氯乙酸。结果表明：在所确立的检测条件下,二氯乙酸、内标和三氯乙酸组分峰在谱图上能够得到很好的分离。低浓度水平和高浓度水平的水样加标回收试验中,二氯乙酸的回收率为91.4%~100.98%,三氯乙酸的回收率为101.47%~115.87%。二氯乙酸的检出限为0.63μg/L,三氯乙酸的检出限为1.02μg/L。综合衍生实验结果考虑,衍生时间确定为2 h。     

转盘塔内甲基异丁基酮萃取湿法磷酸实验研究

溶剂萃取法是一种经济有效的湿法磷酸净化方法。在转盘塔中,以甲基异丁基酮（MIBK）为萃取剂,开展了净化湿法磷酸的实验研究。考察了搅拌转速、相比对磷酸萃取率、杂质离子选择性、洗涤效果和反萃效果的影响。研究结果表明：萃取过程适宜的相比（溶剂与磷酸的体积比）为4,搅拌转速为200~400 r/min,在此条件下磷酸萃取率为85%;洗涤过程的搅拌转速不应大于100 r/min,适宜的洗涤酸用量为溶剂相体积的10%~15%,在此条件下铁离子（Ⅲ）和镁离子脱除率均在90%以上、铝离子脱除率大于70%、硫酸根脱除率为50%~60%;反萃过程搅拌转速不应大于200 r/min,适宜的反萃水用量为溶剂相体积的9%~15%。MIBK对阳离子的脱除效果较好,但是对阴离子的脱除效果不佳。经过萃取、洗涤和反萃3个过程,磷酸收率为57.8%~70.3%,磷酸中铁离子（Ⅲ）含量可以达到工业级磷酸标准,但是硫酸根的含量无法达标,需要结合其他方法进一步脱除。     

Multi response optimisation of polyphenol extraction conditions from grape seeds by using ultrasound assisted extraction (UAE)

Multi response optimisation conditions were investigated in grape seeds’ phenolic compounds extraction by using ultrasound-assisted extraction (UAE) methodology. The effect of independent process variables such as EtOH concentration (0–100%), extraction time (0–40 min), solvent:solid ratio (4.5–38.5 mL/g) and extraction temperature (20–60°C) on total phenolic content (TPC) and total antioxidant activity (TAA) of the extracts were studied. The optimum conditions of UAE were determined as follows: EtOH concentration, 61.76%; extraction time 20 min., solvent:solid ratio, 30 mL/g; extraction temperature 50°C. The estimation results of the model and the experimental results for TPC and TAA showed a great similarity.     

Solvent and Extraction Conditions Control the Assayable Phenolic Content and Antioxidant Activities of Seeds of Black Beans,Canola and Millet

The effects of extraction solvent and conditions on the total phenolic content (TPC) and antioxidant activity of black beans, canola and foxtail millet were investigated. The antioxidant activity was assayed using 2,2‐diphenyl‐1‐picrylhydrazyl radical scavenging activity (DRSA) and oxygen radical absorbance capacity (ORAC). Four solvent systems, namely 70 % acetone, 80 % ethanol, 80 % methanol and a mixture of acetone/methanol/water (7:7:6, v/v/v) were used. The extraction methods adopted in this study included refluxing, homogenization, cold extraction and sonication. The TPC as measured using the Folin Ciocalteu's method were 12.35–28.39, 2.43–16.73, and 1.78–5.06 µmol catechin equivalents/g dry matter (dm) for canola, black beans and foxtail millet, respectively. Aqueous acetone afforded the highest TPC for black beans and canola. Within the same solvent system used, the TPC, DRSA and ORAC obtained from different extraction techniques differed for black beans, canola and foxtail millet. The results demonstrated that the solvent system as well as method influenced the extraction of phenolic compounds and their antioxidant activities, depending on the type of matrix in which phenolics were embedded.     

从生物质直接脱氧液化产物中 提取分离酚类化合物

棉秆直接脱氧液化制备出富含酚类化合物的生物油,将该生物油进行精馏,收集180～260℃的馏分(酚类化合物GC含量高达78.84%),得率约为45%。用1%NaOH碱洗分离油相与水相,水相用有机膨润土吸附和有机溶剂萃取分离,通过GC、GC-MS分析。结果表明,有机膨润土吸附的酚类化合物GC含量为79.13%,有机溶剂萃取分离法可获取纯度较高的酚类化合物,萃取后溶剂中酚类化合物GC含量可高达93.89%,纯度可达93.63%。     

Optimization of the Process for Recovering Phenolic Antioxidant Compounds from Low-Quality Eggplant (Solanum melongena L.) Pulp by Modified Supercritical Carbon Dioxide Extraction

The extraction of biologically active compounds from eggplant pulp by modified supercritical CO₂ extraction was investigated. Response surface methodology was used to optimize the extraction of phenolic compounds and antioxidant capacity by assessing the pressure, temperature, and cosolvent percentage. The results demonstrated that the maximum phenolic content (3,530.79 mg CAE/100 g extract) and antioxidant capacity (4,593.22 μmol TE/g extract) were observed at 56.8°C, 280 bar, and 1.22% of ethanol and were higher than those obtained by conventional solvent extraction. Four phenolic acids were identified in the supercritical extracts and not in the conventional extracts using HPLC-DAD analysis, suggesting that modified supercritical CO₂ extraction is more efficient and selective.