移液管是最广泛使用的实验室设备之一。如果您发现自己在生物化学，分子生物学，生物技术或细胞生物学实验室工作，吸管将迅速成为您的新延长臂。
当用完时，现代液化液允许我们快速，准确，安全地传递微量液体。但事情并不总是这么简单。
Read on to learn about the history of the pipette we know and love, how to pipette with precision, and some techniques that use the pipette.
然后通过帮助食物科学家在我们的遗传修饰玉米的蛋白质含量上进行剥离专业知识进行实践Pipetting simulation．
We should count ourselves lucky
科学家在精致的塑料移液器之前做了什么？
据60年代末，mouth-pipettingwas the widely accepted way of the lab. Mouth-pipetting involves drawing up a solution into a pipette by sucking on it like a straw and transferring it to another vessel. Often single-use glass pipettes had to be individually shaped by hand each time.
On top of being much less accurate, this came with safety consequences. As you can imagine, it wasn’t uncommon to accidentally suck up the solution (often including infectious, toxic or even radioactive substances), contaminate the mouth piece with your fingers, or inhale harmful vapors.
According to a 1966 paper by the U.S. Army Biological Laboratories, the first case of infection by mouth-pipetting was recorded in 1893, when a physician sucked up a mouthful of infectious bacterial culture. Poor guy! In 1915, a survey of 57 labs reported 47 workplace-related infections, and 40% of those were a direct result of mouth-pipetting.
Mouth-pipetting of blood plasma samples at Cambridge University England in 1943 /帝国战争博物馆
你欠德国发明者，Heinrich Schnitger如果您在现代实验室工作，您将不必担心与这些科学家相同的命运。在他的色谱实验结果中缺乏准确性，Heinrich在1957年专利的可拆卸塑料尖端设计了第一活塞驱动的原型。
经济实惠的手动移液器然后在70年代广泛使用，从根本上改变许多科学家的日常生活。在某些实验室中，您甚至可以找到多通道自动移液机器人！
An automated pipetting robot /Andrew Alliance
The improved precision of modern micropipette has the capacity to yield more meaningful experimental results. However, the precision of the pipette is also dependent on the user. So don’t take his invention for granted, and learn the proper technique to allow you to use the pipette to its full potential.
如何用精度吸移
1.挑选正确的移液管
移液器设计用于在给定范围内传输卷。因此，您应该为您旨在转移的音量找到正确的移液器。过低的移液量会导致您失去精度，并且过高的移液量会损坏移液器。
Tip:Often, there’s a clue in the name. Pipettes tend to be named “P”, followed by the maximum volume they can transfer in microlitres (often displayed on top of the plunger). For example, the “P200” should not be used for transferring volumes above 200 microlitres.
2.调整音量
The window with three digits on the side of the pipette displays the volume. Turn the adjustable wheel of the plunger until the volume you’re aiming for is displayed on the readout. The image below shows how to interpret the readout on three different Labster pipettes, P20, P200 and P2000, but these can vary between different pipette models.
3. Add a sterile tip
不要触摸移液管尖端。只需打开移液管尖端，并将移液管牢牢挤压到尖端上以拾取。
4. Pick up the solution
移液管顶部的柱塞有三个位置。它的默认位置是rest position．If you try pushing your thumb gently on the plunger until you feel resistance, you’ll find thefirst stop．到那时紧迫的哈尔der, past the point of resistance, you’ll reach thesecond stop．
要收集解决方案，您首先需要在第一个停止处握住柱塞。垂直保持移液管，将吸移管浸入液体中。通过慢慢地稳定地将柱塞释放回到静止位置，您应该看到解决方案进入尖端。
5.分配解决方案
为了将液体分配到新的血管中，将移液管尖端靠在容器的侧面30-40度，然后缓慢地将柱塞从静止位置稳定地推动到第二止挡。仔细观察，确保尖端没有液体。
6. Eject the tip
通过按柱塞旁边的弹出按钮将尖端弹出到相应的废物箱中。每当你吸移到一个新的解决方案以避免污染时，请记住拍摄新的无菌尖端。
Tip:A good way to test your pipetting technique and calibration is to practice by pipetting water, weighing what you dispense. One microlitre of water weighs 0.001g. If you’re pipetting is on point, you should find that the volume you set your pipette to will correspond to the weight of the water. For example, when your pipette is set to 200 microlitres, the scale should read 0.2g.
那么我可以使用液相用？
Pipetting is a key part of countless lab techniques, but here are just two common techniques requiring good pipetting skills.
串行稀释
Imagine someone brought you a bacterial culture, containing millions of densely packed bacteria, and tasks you with counting how many bacteria are in there.
You could start by diluting the very concentrated sample to a much more dilute sample that is easier to work with, reducing how many bacteria you need to count. Taking into account the dilution factor, you could then work out how many bacteria you started with.
However, diluting very small volumes is very difficult to do accurately. So, instead, you can do a serial dilution. This isn’t when you add milk to your cereal in the morning. A serial dilution is a series of sequential dilutions, each reducing the bacterial concentration by a set amount. For example, you might carry out three 1 in 10 dilutions instead of one 1 in 1000 dilution.
布拉德福德测定
您可能知道蛋白质中有些食物很高，蛋白质对均衡的饮食很重要。但如果有人向你递给你一杯牛奶，并要求你量化它包含多少蛋白质，你会在哪里开始吗？
这样可以做到这一点是使用称为Bradford测定的东西。
布拉德福德测定involves using a dye, Coomassie Brilliant Blue, which binds to proteins producing a blue color. Firstly, you add the dye to solutions with varying,knownprotein concentrations and record how much light the solutions absorb. Absorption is a measure of ‘blueness’, which corresponds to the protein concentration of the solution. Then, add the dye to yourunknownsample, and record its absorbance. By comparing the absorbance of our unknown sample to the known samples, the protein concentration of the unknown can be calculated.
你的挑战
在这些技术上获得良好掌握的最佳方法是尝试自己。
Put what you have learned into practice with the LabsterPipetting simulation．在模拟中，您的挑战是帮助Labsterfood Inc.的食品科学家们希望减少营养不良。你能帮助他发现遗传修饰的玉米棒是否含有足够的赖氨酸，一个必需的氨基酸，以满足成年人推荐的每日剂量？
Check out ourblogfor more stories and learning resources like this.
快乐的脱液！
