Nitrogen purging is mainly used for the concentration and purification of samples. It concentrates the sample to the desired volume by blowing pure nitrogen into the sample solution, which causes the solvent in the solution to evaporate rapidly. Nitrogen blowing instrument is widely used in environmental monitoring, food safety, drug testing and other fields.
Before using a nitrogen blower, you first need to prepare the sample to be processed, the solvent, and the pure nitrogen source. Make sure the power of the nitrogen blower is connected and turned on, and the instrument is warmed up to the appropriate temperature. At the same time, check whether the pressure of the nitrogen cylinder is sufficient, and ensure that the flow rate and pressure of the nitrogen meet the experimental requirements.
The loading steps for the nitrogen purge are as follows:
1.Aspirate the sample solution into the pipette, taking care not to aspirate air bubbles. If the sample contains precipitates or suspended solids, centrifugation or filtration should be performed first.
2.Gently unscrew the cap of the nitrogen blowing tube and insert the pipette into the nitrogen blowing tube without touching the tube wall. The sample solution is then slowly injected into the bottom of the nitrogen blowtube, trying to avoid air bubbles.
3.When removing the pipette, be careful not to allow the sample solution to drip onto the outer wall or lid of the nitrogen blowpipe to avoid cross-contamination.
4.Re-tighten the cap of the nitrogen blowpipe to make sure it is well sealed. Then put the nitrogen blowpipe into the heating hole and adjust the position.
According to the experimental requirements, set the temperature and nitrogen flow rate. In general, the temperature is set between 40-60 and the nitrogen flow rate is adjusted according to the nature of the sample and the concentration rate requirements. For volatile or heat-sensitive samples, the temperature and nitrogen flow should be appropriately reduced.
Open the nitrogen valve and start blowing nitrogen into the nitrogen blowing tube. Observe the change in the sample solution and close the nitrogen valve when the solution volume is concentrated to the target volume. In order to avoid sample loss due to over-concentration, it is advisable to regularly check the volume changes of the sample.
After the concentration is complete, turn off the heating function of the nitrogen purge. After waiting for the nitrogen blowtube to cool to room temperature, gently unscrew the lid and pipette out the concentrated sample. Be careful not to touch the inner wall of the nitrogen blowpipe to avoid contaminating the sample.
After use, clean the nitrogen blowpipe and lid in time to keep the device clean. For contaminated samples, it is recommended to use an appropriate solvent for cleaning so as not to affect the accuracy of subsequent experiments.