Beeswax is a pharmaceutical and cosmetic commodity listed in the
U.S. and EU Pharmacopeias. It is also widely used as a food additive (E 901),
for example, for the coating of fresh fruits, dried fruits, sweets, and
cheeses, as well as a component of different polishing waxes. Beeswax is a very complex mixture of lipophilic
compounds. Mono-, di-, and triesters of long-chain aliphatic alcohols with
fatty acids or hydroxy-fatty acids constitute the largest fraction representing
ca. 65% of the total weight. Free fatty acids, mostly C26 and C30, and
longchain hydrocarbons represent ca. 12% each. Other components of beeswax are
free hydroxy acids, free aliphatic alcohols, and carotenoids. In ancient times
it was believed that beeswax was collected from flowers or made from pollen; it was not until 1744 that H. C.
Hornbostel discovered that it is synthesized by four pairs of wax-secreting
epidermal glands on the ventral side of worker bees’ abdomens. Bees use wax mainly for building the honeycombs; they
remove, reshape, mold, and use it over and over again. The combs are literally
the nursery, walls, storage pantry, home, pharmacy, and dance floor for the colony.1 Pesticides can enter the hive either directly or indirectly.2,3 Various acaricides, such as coumaphos, amitraz, and fluvalinate, are applied in beekeeping for Varroa mite control, but other environmental
contaminants also find their
way into the hive when bees fly around
searching for nectar and pollen. For this reason honey bees and bee products
have been used as bioindicators of environmental pollution in several
countries.4-9 An emerging problem for apiculture is caused
by the fact that beeswax is widely recycled when establishing a new hive, thus
leading to a progressive accumulation of pesticides in it. In several studies
conducted in different
countries, residues of numerous pesticides have been found in beeswax.3,10-16 There are only a few methods described in
the literature for the analysis of pesticide residues in beeswax. The most
reported methodology is the single-residue one.14 There are some other methods for the quantitative analysis of
particular groups of pesticides, such as acaricides11,12 or lipophilic pesticides,17 using either LC or GC techniques.2,3,18 Mullin et al. analyzed 259 real samples from beehives in the
United States covering a very broad scope of GC- and LC-amenable analytes. A
total of 87 different pesticides and metabolites were identified using the QuEChERS approach as sample
preparation method. Nevertheless, the evaluation of the analytical method
employed was not published.19 The
methodologies employed in the studies mentioned above involved mainly beeswax
dissolution followed by liquid-liquid
extraction and solid phase extraction for cleanup. A simple variation of the
QuEChERS method20 allowing the determination of 51 pesticides
in beeswax by LC and GC is presented in this work. Thirteen GC-amenable and 38
LCamenable pesticides employed in this study were selected on the basis of
their relevance for beeswax as reflected by
the frequency of residue findings
in beeswax and other apiarian products according to the literature and the
pesticides-online
2021-09-20
简要介绍 dSPE 在全自动移液工作站上应用实现全自动抗体纯化的原理。
比较了三种 Protein A 纯化 HIgG 的效率及纯化流程优化方法。
使用 IMCSTips 实验全自动纯化(一步)方法及数据分析
2021-09-20
1. IMCStips 应用原理展示
2. His-tagged 蛋白纯化流程优化及数据分析
2021-09-20
IMCStips 亲和层析柱
● 一次层析即可快速产生高纯重组蛋白
● 一致性好、回收率高,个样品的差异不到 10%
● 可结合各种复杂方法的模板化工作流
● 与 Hamilton 移液工作站结合,可在 30 分钟内处理 96 个样品
● 可定制的工作流程
2020-02-08
BenchWaver™ 把传统的平台摇摆运动与轨道振动器的圆周运动结合起来,这种最优组合能够产生最适合分子生物学应用的三维运动。
2020-02-08
强力混匀,适于细胞裂解、研磨或均质
与通用的组织研磨机更快速、更高效
采用密封2.0mL管,消除交叉感染
中通量,可同时处理3~6个样品
无锡微色谱生物科技有限公司
WuXi MicroSep Biological Science Co,. Ltd.
地 址:江苏省江阴市月城镇北环路 19 号
电 话:17715681752
工作时间:周一 ~ 周五 9:00 ~ 16:00