Heavy metal cadmium water quality on-line automatic monitor

The utility model discloses a heavy metal cadmium water quality on-line automatic monitor which is characterized in that a pretreatment filtering structure is used for pre-filtering a water source to be monitored, filtered water enters a water storage tank, and the pretreatment filtering structure is an external device, can simultaneously filter a large amount of water sources, is more convenient to disassemble and clean, and is convenient to use. The filtering time is shortened, hydrolytic precipitation of metal in a water sample is avoided in cooperation with a stirring structure, and the accuracy of a monitoring result is ensured; the inert gas filling structure is adopted to replace gas in the water storage tank with inert gas, air is discharged from the safety overflow valve, redundant gas is also discharged from the safety overflow valve to guarantee use safety, the situation that the pH value is changed due to absorption of acid gas such as CO2 is avoided through inert gas protection, metal desorption