Here's a water-tight clamp used to seal the top of a recovered sampler. This can make decanting the sample easier by clamping the sleeve shut between containers, or sealing the sampler for later use after sample for VOC's has been decanted.
Sampler can be layed down or inverted without loss (check valve needs back-pressure to remain closed).
Remember, fill your VOC's first, standard HydraSleeves are made of LDPE - and some VOC's and some gasses may diffuse out of the sample if left exposed for more than ~10 minutes.