Pipette and liquid transfer straw are basic components in biochemical experiment operations, and are commonly used instruments for measuring liquids. The two are often compared, such as the accuracy and applicability of the two.
So how to choose?
Liquid transfer straw
A liquid transfer straw is a measuring device used to accurately transfer a certain volume of a solution, usually a specially calibrated glass or transparent plastic tube, which is used to hold an accurate volume of a specified fluid.
Principle: The liquid transfer straw is a simple physical structure, generally made of glass or plastic, and the volume is determined by the scale. When calibrating the corresponding scale of the corresponding volume, the quality corresponding to the corresponding volume of distilled water is certain. If the quality of the distilled water discharged after absorbing liquid is “correct”, it means that the volume of distilled water discharged after absorbing liquid is “correct” (reaching the standard Within the allowable error range of the weighing value)”, then the suction volume represented by the tangent point of the concave surface where the distilled water is located is “correct”, and this point is where the scale of the corresponding volume is located. Once this point is determined, the internal volume of the pipette is physically determined, and this volume will hardly change with external factors such as liquid density, air pressure and other factors.
Volume: According to the national standard, the nominal volume range of the fat pipette is 1-100ml, and the commonly used specifications are 5, 10, 25, and 50mL. The nominal capacity range of graduated pipettes is 0.1-50ml, and the commonly used specifications are 1, 2, 5 and 10mL. In general, pipettes and pipettes deliver volumes accurate to 0.01 mL.
Liquid transfer straws are generally made of glass, which cannot withstand acid and alkali, and Teflon plastic FEP/PFA pipettes can be selected.
Liquid transfer straws have high requirements for users and require experienced personnel to measure accurately.
Pipette
Pipette is a kind of liquid transfer equipment, which is often used to pipette a small amount or a small amount of liquid in the laboratory. It can be said to be an “upgraded” version of the pipette. It can be divided according to different standards, such as air displacement pipette according to the working principle. Pipettes and positive displacement pipettes can be divided into manual pipettes and electric pipettes according to the adjustment scale.
Principle: The pipette gun in the general sense is an air piston pipette. When the pipetting button is moved, the position of the internal piston changes, thereby generating negative pressure, thereby sucking the liquid into the tip. The determination of the suction volume is determined by the internal and external pressure difference and a series of other factors, but the main determinant is the internal and external pressure difference. When calibrating, if the mass of distilled water absorbed is “correct” (weighing method), it means that the volume of distilled water discharged after absorbing liquid is “correct (within the error range allowed by the nominal value)” , then the volume represented by the aspiration is “correct”. Therefore, when using distilled water to determine the pipetting volume of a pipette, what is actually determined is that the combined effect of the internal and external pressure difference of the pipette and a series of other factors can just absorb the correct volume of distilled water.
Volume: According to the “JJG646-2006 Pipette Verification Regulations”, the nominal capacity of the pipette ranges from 1 ul to 10000 ul. In terms of range, pipettes and pipettes overlap, but pipettes have a smaller measurement range. Now some micro-capacity pipettes can measure up to 0.1 ul, which is suitable for more demanding experimental activities.
The pipette does not have high requirements for the operation of the user, as long as the basic operation techniques are mastered, it can be measured.
Pipettes work efficiently, but the price will be higher than liquid transfer straw.
PFA/FEP Pipette tips
Ordinary plastic pipette tips are not reusable and need to be replaced constantly, resulting in high cost;
Customizable PFA/FEP pipette tips, acid and alkali resistance, low metal blank value, factory direct sales, can match different types of pipettes.
Features:
1. High and low temperature resistance: the operating temperature can reach -200~260°C;
2. Has extraordinary chemical resistance, such as: aqua regia, hydrofluoric acid, nitric acid, hydrochloric acid, sulfuric acid, magic acid, acetone, alcohols, alkali solvents, etc.;
3. Accept samples from customers to customize PFA/FEP pipette tips;
4. Meet the needs of various analytical laboratories for small sample transfer and liquid dilution;
5. PFA/FEP Teflon microtips are resistant to acid, alkali and corrosion, and are divided into two types: scale and no scale;
6. According to the requirements of customers, special marking machines can be used for scale marking, but this scale line is for reference only and cannot be used as a strict quantitative standard;
7. It is mainly used in laboratories such as ICP-MS, ICP-OES and other trace analysis and isotope analysis. It is used for a small amount of pipetting in some institutions such as geology, electronic chemicals, semiconductor analysis and testing, disease control centers, pharmaceutical factories, and environmental testing centers.