The core principle of the precise concentration technology of the fully automatic nitrogen blowing instrument lies in the synergistic effect of nitrogen blowing and temperature control, which accelerates solvent evaporation through physical means and achieves efficient and precise concentration of samples.

Nitrogen purging: the driving force for accelerating solvent evaporation

The fully automatic nitrogen blower uses high-purity nitrogen gas (purity ≥ 99.99%) to blow vertically onto the surface of the sample through a needle or nozzle at a stable flow rate (0.1-10L/min). As an inert gas, nitrogen can not only isolate oxygen and prevent sample oxidation or decomposition, but also form a local gas flow layer on the surface of the sample, reduce the vapor pressure of the solvent surface, break the equilibrium state of the gas-liquid interface, and promote the continuous evaporation of the solvent. During this process, the flow of nitrogen rapidly carries away the solvent vapor on the surface of the sample, forming a strong gas-liquid interface disturbance and significantly improving the evaporation efficiency.

Temperature control: the key to improving evaporation rate

Nitrogen blowers are usually equipped with water baths or dry heating modules, which achieve precise temperature control through temperature sensors and PID controllers (adjustable from room temperature to 150 ℃). For every 10 ℃ increase in temperature, the evaporation rate can be increased by 2-3 times, especially suitable for the volatilization of high boiling point solvents (such as dimethyl sulfoxide, boiling point 189 ℃). Water bath heating achieves uniform heat transfer through constant temperature water circulation, suitable for temperature sensitive samples; Dry heating conducts heat directly through metal blocks, resulting in faster heating and suitable for high-throughput processing.

Dynamic balance: precise matching of parameters

During the concentration process, the nitrogen flow rate, heating temperature, and sample volume need to be dynamically matched. The combination of low flow rate and low temperature is suitable for volatile or thermosensitive samples (such as vitamins and antibiotics) to avoid decomposition; The combination of high flow rate and high temperature is suitable for high boiling point or large volume samples (such as environmental water samples), reducing processing time. When the solvent evaporates to a near dry state, it is necessary to reduce the nitrogen flow rate or stop heating to prevent sample loss or coking. This flexible regulation method enables the nitrogen blower to adapt to diverse sample processing needs.