Tea saponin additive to extract eleutheroside B and E from Eleutherococcus senticosus by ultrasonic mediation and its application in a semi-pilot scale

The safety of ethanol in operations and its effects on human health are gradually being questioned. Under this premise, we attempted to use the natural surfactant tea saponin, which originates from the processing residues of camellia oil, as the additive of the extraction solvent and to extract eleutheroside B and eleutheroside E in the roots and rhizomes of E. senticosus by ultrasonic mediation. After a single-factor experiment, extraction kinetics at different powers and reaction temperatures, and Box–Behnken design optimization, the optimal conditions obtained were 0.3% tea saponin solution as the extraction solvent, 20 mL/g liquid–solid ratio, 250 W ultrasonic irradiation power (43.4 mW/g ultrasonic power density) and 40 min ultrasonic irradiation time. Under optimal conditions, satisfactory yields of eleutheroside B (1.06 ± 0.04 mg/g) and eleutheroside E (2.65 ± 0.12 mg/g) were obtained with semi pilot scale ultrasonic extraction equipment. The experiments showed that compared with the traditional thermal extraction process, the extraction time is significantly reduced at lower operating temperatures.     

稀土矿区茶叶中稀土元素ICP-AES测定

本文用ＩＣＰ－ＡＥＳ测定稀土矿区茶叶中稀土元素，并用干扰系数法校正茶叶中的无机元素及其他稀土元素对待测稀土元素的光谱干扰。在最佳工作条件下，测定了茶叶样品中的稀土元素含量。     

氢化物发生-原子荧光光谱法测定茶叶中的铅

氢化物发生-原子荧光光谱法测定茶叶中铅,在优化的分析条件下,相对标准偏差0.68%,回收率104%,用于标准样品(GBW08505)测定,结果与标准值吻合。该方法用于实际样品测定,与石墨炉原子吸收法对比,结果令人满意。     

UE/ME-GC-MS提取分析普洱茶的挥发和半挥发性成分

采用超声波提取（UE）和微波萃取（ME）两种前处理方法提取普洱茶的挥发性成分,利用气相色谱-质谱（GC-MS）联用仪进行定性检测,并加入乙酸苯乙酯作为内标进行定量分析。结果表明：两种萃取方法共鉴定出挥发性成分88种,其中超声波萃取检测出79种,微波萃取检测出69种。普洱茶的主要挥发性成分有11,14,17-二十三碳烯酸甲酯、咖啡因、棕榈酸、维生素E、β-香树脂醇、植醇等。超声波萃取法得到的提取率较高,而微波提取法耗时较短,两者各有所长,应根据需要来选择。     

萘茜光度法直接测定茶叶中的微量铜

茶叶中含有许多对人体有益的微量元素 (如Cu ,Zn ,Mn等 )而倍受人们的青睐。在中国、日本和许多其他国家都有茶文化。因此 ,有必要对茶叶中微量元素的含量进行准确测定。目前微量铜的测定方法有火焰原子吸收光谱法[1 ,2 ] 、荧光法[3,4] 、分光光度法[5～8] 和流动注射分析法[9～ 1 2 ] 。测定铜方法很多 ,由于分光光度是一种经典的方法 ,具有快速、灵敏度高 ,选择性好 ,特别是不要求贵重仪器等特点 ,它仍是检测铜重要手段之一。本文研究发现 ,在 0 1mol·L- 1 NH4Ac介质中 ,在表面活性剂SDS的存在下 ,痕量Cu(Ⅱ )与 5 ,8 二羟基 1 ,4 萘醌 (Naph)络合具有灵敏的显色反应 ,有色络合物的最大吸收波长为 330nm ,而Naph的最大吸收波长为5 1 5nm ,建立了测定痕量Cu(Ⅱ )的分光光度法。本法快速准确、灵敏度高 ,选择性好 ,可满意地测定茶叶中的微量铜。     

吖啶橙-罗丹明6G能量转移荧光猝灭法定量测定茶多酚

在λex/λem=450/556 nm,十二烷基苯磺酸钠(DBS)存在下,吖啶橙(AO)-罗丹明6G(R6G)间能够发生有效的能量转移,使R6G荧光大大增强。酸性条件下,茶多酚的加入使体系R6G的荧光发生猝灭。利用AO-R6G能量转移荧光猝灭法定量测定茶多酚,提高了测定的灵敏度和选择性。茶多酚含量在0.75~60mg/L范围内与R6G荧光猝灭程度呈良好线性关系,方法检出限为0.35 mg/L。6次平行测定样品相对标准偏差1.36%~2.17%,回收率为93%~107%。该方法用于茶叶样品中茶多酚含量的测定,结果满意。     

Determination of carbendazim in tea using surface enhanced Raman spectroscopy

Surface-enhanced Raman scattering(SERS) is applied to detect the concentration of carbendzim(CBZ) in tea leaves. Au colloid is selected and used for active surfaces, and the extraction conditions are optimized in the experiment. The linearity range for the SERS intensity and the concentration of CBZ is found to be0.5 to 8 mg kgà1. The detection limit for CBZ is 0.1 mg kgà1and its recovery in tea samples is 72.3%. The detection results for CBZ using this method are compared with those of HPLC, and no obvious difference can be found. In addition, by dripping the condensed Au colloid on the tea leaves, the proposed SERS approach could be used to the in-situ determination of the half life period of CBZ on tea leaves.     

A novel spectrophotometric determination of copper(Ⅱ) with bromosulphonazo Ⅲ

A novel ehromogenic reaction involving copper(Ⅱ) and bromosulphonazo Ⅲ (Br-SAZⅢ) in hexamethylenetetramine-hydrochloric buffer solution was investigated. The results showed that a blue complex of copper(Ⅱ) and bromosulphonazo Ⅲwas formed with a molar ratio of 1:1. The apparent molar absorptivity was 3.3 × 105Lmol-1cm-1 and themaximum absorption peak was at 616.8 nm. The proposed procedure was used for quantitative estimation of Cu(Ⅱ) inthe concentration range of 0-1.024 μg/mL with the detection limit (3σ) of 7.03 × 10-4 μg/mL (n = 20). The relativestandard deviations (RSDs) were 0.56-4,68%. Under the optimized conditions, total copper in the vegetables and tea wassuccessfully determined.     

反相高效液相色谱法测定可乐、茶叶中的咖啡因

研究了反相高效液相色谱法（RP－HPLC）直接测定茶叶水提取物、可乐饮料中的咖啡因的新方法，采用PE－C18柱，以CH3OH－H2O－HAc(30:69.92:0.08)溶液作流动相，紫外检测波长为260nm。可在8min内将咖啡因与基体分离，咖啡因含量与峰面积在10μg/mL－100μg/mL范围呈线性关系，回归方程为：Y＝33567c(μg/mL)-126421,r=0.9997.该法可用于可乐饮料，茶叶产品质量的监控及产品真伪的辨别。     

用荧光探针法研究茶叶花粉黄酮对氧自由基致鼠红细胞膜氧化损伤的保护作用

应用1,6-二苯基-1,3,5-已三烯(DPH)为荧光探针,超氧阴离子自由基和羟基自由基致鼠红细胞膜氧化损伤为模型,研究了茶叶花粉黄酮对鼠红细胞膜氧化损伤的影响.结果表明,超氧阴离子自由基和羟基自由基均能引起鼠红细胞膜脂质过氧化反应,脂质过氧化产物丙二醛含量显著升高,膜脂流动性下降.将鼠红细胞膜预先用茶叶花粉黄酮处理后,膜脂的MDA含量明显下降,呈现剂量与效应关系,膜脂流动性显著提高,表明茶叶花粉黄酮对超氧阴离子自由基和羟基自由基引起的鼠红细胞膜的氧化损伤有保护作用.