a sample collector, wherein the sample collector is used for collecting a single-molecule sample from a target solvent, and the sample collector comprises a first sample collector and a second sample collector, wherein the first sample collector is configured to collect a first sample, the second sample collector is configured to collect a second sample, and a relative molecular mass of the first sample is different from a relative molecular mass of the second sample;

the first sample collector comprises a housing and a liquid inlet pipe, an absorption chamber configured to store a solvent is formed in the housing, the liquid inlet pipe is communicated with the target solvent and the absorption chamber, the liquid inlet pipe comprises a dispersion part, and the dispersion part is located in the absorption chamber;

a sample storage device, wherein the sample storage device is configured to store the single-molecule sample collected by the sample collector, the sample storage device comprises a first memory and a second memory that are capable to rotate, wherein the first memory is connected to the first sample collector and configured to store the first sample, and the second memory is connected to the second sample collector and configured to store the second sample; and

a controller, wherein the controller is configured to obtain the relative molecular mass of the first sample and the relative molecular mass of the second sample, and controlling a rotating speed of the first memory and a rotating speed of the second memory according to the relative molecular mass of the first sample and the relative molecular mass of the second sample.