Trypsin (CAS 9002-07-7): storage and disposal

The sign on the bottle tells you the form, and supplier labels often state a cold storage requirement, so check them before choosing a shelf. Keep the powder in a tightly closed, labelled tub in a dry store, because dust is the classified hazard, away from food and drink. Solutions should be dated and stored as the label says, in a laboratory fridge or freezer rather than a food unit. On a pathology bench, keep bottles away from clinical samples and acids that may leak. Do not shake the powder out to measure it near other people.

Powder shows damp as caking or a sticky patch, and may smell stale, but enzymes can lose activity without visible change. Solution bottles show more: cloudiness, flecks or a skin, a changed colour, or a leaking cap. Because trypsin is a protein that can digest itself over time in solution, a bottle held warm or for a long period is the likeliest to be spent. A missing date or label means nobody can say how old it is. Record the form, the appearance and the cap condition, and do not open a cloudy bottle.

By specialist collection only. It never goes down the drain or into general waste. It is normally packed in a non-regulated or low hazard laboratory pack with compatible chemicals.

Powder and solution are grouped and packed as separate items, since a liquid bottle is packed differently from a dry tub. Both leave by specialist collection in UN approved packaging under waste code 16 05 06*, with 18 01 06* in a pathology or histology setting. Because inhaling dust is a classified concern, the jar stays closed and nobody should tip powder out to tidy the load. A drain, sink or general bin is not a route for either form, and a spoiled solution should not be poured away. Record the label wording and approximate quantity.

Usually held as: solid, solution.

Part-used bottles and full containers are both fine. Tell us the size and how many, and an estimate is enough for a first price.