The invention discloses a preserving fluid for stably preserving sample
DNA at normal temperature and a preparation method thereof, and belongs to the technical field of biological sample preservation. The preserving fluid comprises a
lysis system, a
nucleic acid protection system and a buffering and stabilizing
system, the
cracking system comprises a composite surfactant and an enzymolysis auxiliary agent; the
composite surface active agent is prepared from polyether
polyol fatty acid ester and cocamidopropyl hydroxy sulfobetaine; the enzymolysis auxiliary agent comprises
lysozyme Lyso-V and
protease K; the
nucleic acid protection system comprises a
nitrogen heterocyclic
polyamine-
carboxylic acid derivative and
dextran sulfate; the
nitrogen heterocyclic
polyamine-
carboxylic acid derivative comprises 1, 4, 7, 10-tetraazacyclododecane-N, N ', N' ', N ''tetraacetic acid, 1, 4, 7-triazacyclononane-N, N', N''-triacetic acid, disodium
ethylene diamine tetraacetate-
nitrogen heterocyclic derivative, and
diethylenetriamine pentaacetic acid-
piperazine derivative, and the nitrogen heterocyclic
polyamine-
carboxylic acid derivative comprises 1, 4, 7, 10-tetraazacyclododecane-N, N ', N '', N'' tetraacetic acid, 1, 4, 7-triazacyclononane-N, N', N ''-triacetic acid. The buffering and stabilizing system comprises an amphoteric
buffering agent and a
polymer stabilizer; the amphoteric
buffering agent comprises 2-(N-
morpholino)
ethanesulfonic acid and N-tri (
hydroxymethyl) methylglycine.