Influencing factors of solid phase extraction efficiency and brief description of nitrogen blowing instrument

Influencing factors of solid phase extraction efficiency and brief description of nitrogen blowing instrument

We use a solid phase extraction instrument, and Zui cares about the extraction effect. However, there are several factors that affect the extraction efficiency:
(1) Filler (stationary phase) - Core Choosing the right SPE column packing is a prerequisite for ensuring the desired results.
(2) Strength of elution solvent 1. Using a normal phase stationary phase, the solvent strength is enhanced with the increase of its polarity. 2. Using a reverse stationary phase, the solvent strength is enhanced with the weakening of its properties. (3) PH value ion exchange fixation The PKa of the phase, analyte and interfering substance are different. By adjusting the pH, the stationary phase can be charged, the analyte is charged oppositely, and the interfering substance is not charged; or conversely, the stationary phase is charged, and the interfering substance is charged oppositely, so that the analyte does not carry The charge is used for the purpose of separation and purification.

At present, nitrogen blowers are also called nitrogen blow dryers, automatic fast concentrators, etc. There are two types on the market: dry nitrogen blowers and water bath nitrogen blowers. Nitrogen blowing instruments have been accepted and accepted by more and more people instead of traditional rotary evaporators.
1. How the nitrogen blower works We know that there are two ways to speed up evaporation: to strengthen the air flow around it and its temperature. Nitrogen is an inert gas that acts as a barrier to oxygen and prevents oxidation. The nitrogen blowing instrument uses the rapid flow of nitrogen to break the gas-liquid equilibrium over the liquid, thereby accelerating the liquid volatilization speed; and raising the temperature by dry heating or water bath heating (the boiling point of the target is generally higher than the solvent), thereby Achieved the purpose of concentration.
2. The main components of the nitrogen blower mainly include gas distribution chamber, gas needle, height adjustment bracket, nitrogen interface, highly fine-tuned components, pillars, fixed components, chassis, bushings, heating blocks, sample tubes or test bottles.
3. How to use the nitrogen blower (take the water bath nitrogen blower as an example)
After the nitrogen blowing instrument is installed, the chassis is supported in a constant temperature water bath, the water bath power is turned on, the water bath temperature is set, and the water bath starts to heat. The nitrogen blowing instrument is lifted, and the samples that need to be evaporated and concentrated are respectively placed on the sample positioning frame, and are lifted by the tray, wherein the height of the tray and the positioning frame can be adjusted according to the size of the test sample tube. Open the flow meter needle valve, and the nitrogen gas reaches the gas distribution plate through the flow meter and the gas supply pipe. After the gas is distributed, it is sent to the needle valve tube (mounted on the gas distribution plate) above each sample position. Then, by adjusting the needle valve needle, nitrogen is blown to the liquid sample tube through the needle valve tube and the needle. The needle valve tube can be slid up and down by adjusting the lock nut, the needle height is adjusted, and the sample surface is corrugated, and the sample is not Splashing is better. After the zui, the nitrogen blower was placed in a water bath until evaporation and concentration was completed.
4. Advantages of Nitrogen Blowing Apparatus (1) It can process multiple samples at a time, and the advantages are more obvious in multi-factor and multi-level repeated experiments.
(2) The experimental operation is simple and flexible. The process of concentration can be adjusted at any time without restriction.
(3) The operator does not need long-term maintenance during the experiment, saving manpower.
(4) The nitrogen blowing instrument is accurate and sensitive during concentration to avoid sample loss.
5. Application field of nitrogen blowing instrument Nitrogen blowing instrument is mainly used for purification and preparation of analytical samples such as chromatography and mass spectrometry. It is widely used in the evaporation of water, toluene, methanol, acetone and other solvents. Application areas are:
(1) Analysis of pesticide residues: such as Vegetables, Fruits , grains, plant tissues (2) Environmental analysis: such as drinking water, groundwater and contaminated water samples (3) Pharmaceutical drug testing: such as traditional Chinese medicine (4) biological analysis: such as serum, Plasma, blood, urine (5) commodity inspection: tests such as dioxins,croft, etc. (6) food and beverage: such as milk, wine, beer, liquid beverage

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