How to prepare the samples for saliva

 1. Collection the Saliva after Centrifugation,then use the pbs to dilute it slowly,the dilution rate is  1:1.(For example,add 0.1ml pbs to 0.1ml saliva and mix them well,then cryopreservation)

2. PBS concentration was 0.01 mol, pH was controlled between 7.2-7.4