原子吸收光谱法测定比较5种不同品牌茶叶中微量元素含量

对市售茶叶崂山绿茶、茯茶、安溪铁观音、乌龙茶、茉莉茶王中微量元素Ca、Mg、Fe、Cu、Zn的含量进行考察.采用V(高氯酸)∶V(硝酸)=1∶4混酸消解的方法将样品在低温下消解,火焰原子吸收光谱法定量.实验测得5种茶叶中均含丰富的Ca、Mg,其中茯茶含Fe最多;崂山绿茶含Cu最多;安溪铁观音和崂山绿茶含Zn多.各元素工作曲线相关系数r0.9948,加标回收率94.38%～105.00%,相对标准偏差在2.26%以下.实验方法快速、定量准确,测得各品牌茶叶中微量元素含量可为消费者提供参考.     

火焰原子吸收光谱法测定三种产地黑米中微量元素含量

用微波消解黑米样品,火焰原子吸收光谱法测定了3个不同产地黑米中Fe、Cu、K、Mn、Mg、Zn 6种微量元素含量。结果表明,微波消解时间短,操作简单,节省试剂,环境污染少,各元素回收率在95．2％～103．5％之间,相对标准偏差（RSD）均〈5％。     

Identification of Key Aroma Compounds Responsible for the Floral Ascents of Green and Black Teas from Different Tea Cultivars

Chemicals underlying the floral aroma of dry teas needs multi-dimensional investigations. Green, black, and freeze-dried tea samples were produced from five tea cultivars, and only ‘Chunyu2’ and ‘Jinguanyin’ dry teas had floral scents. ‘Chunyu2’ green tea contained the highest content of total volatiles (134.75 μg/g) among green tea samples, while ‘Jinguanyin’ black tea contained the highest content of total volatiles (1908.05 μg/g) among black tea samples. The principal component analysis study showed that ‘Chunyu2’ and ‘Jinguanyin’ green teas and ‘Chunyu2’ black tea were characterized by the abundant presence of certain alcohols with floral aroma, while ‘Jinguanyin’ black tea was discriminated due to the high levels of certain alcohols, esters, and aldehydes. A total of 27 shared volatiles were present in different tea samples, and the contents of 7 floral odorants in dry teas had correlations with those in fresh tea leaves (p < 0.05). Thus, the tea cultivar is crucial to the floral scent of dry tea, and these seven volatiles could be promising breeding indices.     

不同产地柴胡中微量元素的测定分析

分别采用火焰原子吸收法测定了不同产地柴胡中微量元素钙、镁、铁、铜、锌的含量。结果表明,柴胡中富含对人体有益的钙、镁、铁、铜、锌等微量元素,且不同产地柴胡中各微量元素含量有所差异,为鉴别药材的产地特征及柴胡药效功能的研究和利用提供了依据。     

An RP-LC-UV-TWIMS-HRMS and Chemometric Approach to Differentiate between Momordica balsamina Chemotypes from Three Different Geographical Locations in Limpopo Province of South Africa

Momordica balsamina leaf extracts originating from three different geographical locations were analyzed using reversed-phase liquid chromatography (RP-LC) coupled to travelling wave ion mobility (TWIMS) and high-resolution mass spectrometry (HRMS) in conjunction with chemometric analysis to differentiate between potential chemotypes. Furthermore, the cytotoxicity of the three individual chemotypes was evaluated using HT-29 colon cancer cells. A total of 11 molecular species including three flavonol glycosides, five cucurbitane-type triterpenoid aglycones and three glycosidic cucurbitane-type triterpenoids were identified. The cucurbitane-type triterpenoid aglycones were detected in the positive ionization mode following dehydration [M + H − H₂O]⁺ of the parent compound, whereas the cucurbitane-type triterpenoid glycosides were primarily identified following adduct formation with ammonia [M + NH₄]⁺. The principle component analysis (PCA) loadings plot and a variable influence on projection (VIP) analysis revealed that the isomeric pair balsaminol E and/or karavilagen E was the key molecular species contributing to the distinction between geographical samples. Ultimately, based on statistical analysis, it is hypothesized that balsaminol E and/or karavilagen E are likely responsible for the cytotoxic effects in HT-29 cells.     

FAAS法测定新疆两种不同产地沙枣中的6种微量元素

目的建立沙枣中Ca、Mg、Cu、Zn、Fe、Mn等6种微量元素的火焰原子吸收光谱法。方法在确定的火焰原子吸收光谱法检测条件下,使用马弗炉处理样品,对新疆两种不同产地的沙枣中Ca、Mg、Cu、Zn、Fe、Mn等6种微量元素的含量进行了测定。结果各元素的回收率（／Z=5）在97．50％～104．60％之间,RSD（n=5）在1．61％～3．51％之间。结论该法简单、快速,具有很好的精密度和灵敏度,适用于沙枣中6种微量元素的测定。     

Characterization of the Volatile Compounds in Camellia oleifera Seed Oil from Different Geographic Origins

Volatile flavor of edible oils is an important quality index and factor affecting consumer choice. The purpose of this investigation was to characterize virgin Camellia oleifera seed oil (VCO) samples from different locations in southern China in terms of their volatile compounds to show the classification of VCO with respect to geography. Different samples from 20 producing VCO regions were collected in 2020 growing season, at almost the same maturity stage, and processed under the same conditions. Headspace solid-phase microextraction (HS-SPME) with a gas chromatography–mass spectrometer system (GC–MS) was used to analyze volatile compounds. A total of 348 volatiles were characterized, including aldehydes, ketones, alcohols, acids, esters, alkenes, alkanes, furans, phenols, and benzene; the relative contents ranged from 7.80–58.68%, 1.73–12.52%, 2.91–37.07%, 2.73–46.50%, 0.99–12.01%, 0.40–14.95%, 0.00–27.23%, 0.00–3.75%, 0.00–7.34%, and 0.00–1.55%, respectively. The VCO geographical origins with the largest number of volatile compounds was Xixiangtang of Guangxi (L17), and the least was Beireng of Hainan (L19). A total of 23 common and 98 unique volatile compounds were detected that reflected the basic and characteristic flavor of VCO, respectively. After PCA, heatmap and PLS-DA analysis, Longchuan of Guangdong (L8), Qingshanhu of Jiangxi (L16), and Panlong of Yunnan (L20) were in one group where the annual average temperatures are relatively low, where annual rainfalls are also low. Guangning of Guangdong (L6), Yunan of Guangdong (L7), Xingning of Guangdong (L9), Tianhe of Guangdong (L10), Xuwen of Guangdong (L11), and Xiuying of Hainan (L18) were in another group where the annual average temperatures are relatively high, and the altitudes are low. Hence, volatile compound distributions confirmed the differences among the VCO samples from these geographical areas, and the provenance difference evaluation can be carried out by flavor.     

ICP-MS Assessment of Essential and Toxic Trace Elements in Foodstuffs with Different Geographic Origins Available in Romanian Supermarkets

The present study was conducted to quantify the daily intake and target hazard quotient of four essential elements, namely, chromium, cobalt, nickel, and copper, and four toxic trace elements, mercury, cadmium, lead, and arsenic. Thirty food items were assigned to five food categories (seeds, leaves, powders, beans, and fruits) and analyzed using inductively coupled plasma-mass spectrometry. Factor analysis after principal component extraction revealed common metal patterns in all foodstuffs, and using hierarchical cluster analysis, an association map was created to illustrate their similarity. The results indicate that the internationally recommended dietary allowance was exceeded for Cu and Cr in 27 and 29 foodstuffs, respectively. According to the tolerable upper level for Ni and Cu, everyday consumption of these elements through repeated consumption of seeds (fennel, opium poppy, and cannabis) and fruits (almond) can have adverse health effects. Moreover, a robust correlation between Cu and As (p < 0.001) was established when all samples were analyzed. Principal component analysis (PCA) demonstrated an association between Pb, As, Co, and Ni in one group and Cr, Cu, Hg, and Cd in a second group, comprising 56.85% of the total variance. For all elements investigated, the cancer risk index was within safe limits, highlighting that lifetime consumption does not increase the risk of carcinogens.     

电感耦合等离子体质谱法(ICP-MS)测定汤岗子热矿泥黑粉中16种矿物元素

对汤岗子热矿泥黑粉中矿物元素进行了分析研究。用微波消解法处理汤岗子热矿泥黑粉样品,采用ICP-MS法对热矿泥黑粉中16种元素进行分析。结果表明,在优化实验条件下,方法的检出限为0.00028～14.66μg/L,相对标准偏差为0.18%～6.20%,回收率为91.5%～108.2%。为探讨汤岗子热矿泥黑粉对人体的保健作用提供了参考数据。     

Analytical investigation of secondary metabolites extracted from Camellia sinensis L. leaves using a HPLC‐DAD‐ESI/MS data fusion strategy and chemometric methods

Considerable attention has been paid to the study of green tea leaves because of their high consume and beneficial effects on human health. In this work, an appropriate strategy is proposed to investigate and resolve the major metabolites extracted from Camellia sinensis tea leaves. Statistical design mixtures of ethanol, ethyl acetate, dichloromethane, and chloroform were used to study the effects of different solvents and their mixtures on the extraction of the secondary metabolites of C. sinensis tea leaves from two different harvest seasons. Extracted samples were analyzed by high performance liquid chromatography‐diode array detection‐electrospray ionization mass spectrometer allowing the resolution of a large amount of tea metabolites with high relative abundances, especially when their extraction was performed in pure ethanol and with solvent mixtures with ethanol. Resolution of the more relevant metabolites was achieved by the simultaneous analysis of the fused diode array detection and mass spectrometer detectors data from the same samples using the multivariate curve resolution‐alternating least squares chemometric method. Peak areas finally resolved were further analyzed by orthogonal signal correction and partial least squares‐discrimination analysis to discriminate among C. sinensis tea samples. Using the Variable Importance in Projection variable selection method, epigallocatechin and caffeine were finally selected as the two more important chemical constituents of tea leaves that were discriminating more between the tea samples from two different harvest seasons. Copyright © 2016 John Wiley & Sons, Ltd.     

Metabolomics Provides A Novel Interpretation of the Changes in Main Compounds during Black Tea Processing through Different Drying Methods

This study aimed to compare the effect of hot roller (HR) drying and hot air (HA) drying on the sensory evaluation, chemical quality, antioxidant activity, and metabolic profile of Yihong Congou black tea processed from E’cha NO1. The Yihong Congou black tea dried with HA obtained higher sensory scores and better chemical qualities such as the hue of tea brew color (a and b), content of theaflavins, thearubigins, water extract, free amino acids, tea polyphenol, and the ratio of polyphenol to amino acids as well as higher antioxidant capacities compared to that dried with HR. The HA drying tea increased the contents of volatile compounds that had positive correlation with sweet and flowery flavor, while the HR drying tea increased the contents of volatile compounds related to fruity flavor. Moreover, non-targeted metabolomics data indicated that the levels of most free amino acids significantly increased, while the levels of most soluble sugars reduced in the HA drying method compared to the HR drying method. The metabolic analysis was also consistent with the above results and revealed that D-ribose and gallic acid were the main characteristic metabolites of HA drying. Our results could provide a technical reference and theoretical guide to processing a high quality of Yihong Congou black tea.     

HS-SPME/GC-MS结合化学计量学分析不同产地路路通中的挥发性成分

采用顶空固相微萃取结合气相色谱-质谱技术(HS-SPME/GC-MS)分析了不同产地路路通中的挥发性成分,采用正交试验设计优化了影响顶空固相微萃取技术的各项因素,以主成分分析、聚类分析两种化学计量学方法分析评价了8个产地路路通的挥发性成分。优化实验结果为1 g样品量在80℃下提取40 min,解析1 min。8个产地的路路通共鉴定出48种挥发性组分,不同产地的化学成分大致相同,含量差异较大。两种统计分析方法均表明,湖南、江苏、四川、辽宁4个产地的路路通挥发性成分比较相似,贵州、广西、安徽、河北4个产地的路路通比较接近。主成分分析结果表明,氧化石竹烯、δ-杜松烯、橙花叔醇可作为区分两大类路路通的代表性化合物。HS-SPME/GC-MS结合化学计量学方法可以有效地对不同产地的路路通进行质量评价,从而为中药路路通的药物开发和科学栽培管理提供重要参考。