how do we keep sampling

[ikin]

hai,
i got i question, how do we keep the sample last in bottle. my sample is powder. because when i kept it in the fridge for a certain period, my sample contaminated very easy (got mold and microob growth) when i do testing. is that any recommendation about type of bottle that i should use or suitable environment to keep it for last longer

tq

[CrowSan]

This is an incredibly general question not knowing what the powder is or the conditions you are working in so I can only answer in a general way:

If you have a cell culture cabinet or other sterile environment you could always use this to remove powder aliquots (spraying the bottle with 70% ETOH before you enter the hood/cabinet).

Obviously always wearing gloves will help (you could spray gloves with 70% ETOH or a biocide before you open the bottle and always remove samples with a sterile implement).

Depending upon the nature of the sample you could store at -20o or -80oC (although check that this will not destroy or change the powders characteristics).

Alternatively you could divide the sample into sterile tubes (such as 50 ml Falcon tubes) when you obtain it and store them individually at 4oC. This would avoid repeated "dipping" into the sample. This may not eliminate the problem but should reduce the chance of contamination (which comes from the environment and yourself).

Sorry can't be more help

CrSn

[relaxin]

The stability of the sample determines the temperature of its storage. If you just want to keep mold and microbe from growing in your sample, I think you can keep your sample at -20 C inside a desiccator. A simple desiccator is a wide-mouth mayonnaise jar filled with Drierite to 1/4 full.