Small-size sequential injection nitride analysis system

The invention relates to a small-size sequential injection nitride analysis system. A first electromagnetic valve is connected with a nitride standard solution; a second electromagnetic valve is connected with a development agent and deionized water; the first electromagnetic valve and the second electromagnetic valve are both connected to a third electromagnetic valve; the third electromagnetic valve is also connected to a fourth electromagnetic valve connected with a water sample; a fifth electromagnetic valve is connected with the deionized water and a waste liquid bottle with a liquid level detection device; a fourth electromagnetic valve and a fifth electromagnetic valve are respectively connected to a six-way valve through a first peristaltic pump and a second peristaltic pump; the six-way valve is connected with waste liquid, a quantifying ring and a colorimetric match pool respectively. On the basis of theories of an improved sequential injection analysis method and a spectrophotometric method, the system has the advantages of simple structure, simplicity in operation, quantification precision, high stability, high reproducibility, high precision, low detection limit and the like; and in actual application, the system is portable and can perform full-automatic real-time on-line monitoring.