Signal solar FID uses hydrogen and air combustion to generate flame as the energy source. When organic compounds enter the flame, due to the ionization reaction, they generate ions several orders of magnitude higher than the base flow. Under the action of electric field, these positively charged ions and electrons move to the negative electrode and the positive electrode respectively to form the ion flow. After the ion flow is amplified, it can be detected. FID is a universal detector with high sensitivity, which can reach (10-12 ~ 10-13) g · s-1