I welcome you again to this next instruction video which is on the water chemistry respective

the taking of the samples for the water chemistry analysis later in the laboratory which is

then done for cations or anions by for example ICPMS or ion chromatography.

And for this chemistry sampling we need different items.

First our water sample of course so just imagine again this is taken from the river behind

me so we just took out this sample here from the river water.

We need a syringe, a filter, a disc filter which is 0.45 micrometers separating the particulate

organic or the particulate stuff in our water sample because we don't want to have these

particulate matter into our chemistry sample so the samples need to be filtered in the

field.

And of course we need our sample vials which for chemistry is ideally a plastic not glass

so in this case we have Falcon tubes 5015 ml which are made I guess from polypropylene

also HDPE high density polyethylene would be fine for taking chemistry samples.

I advise you not to take glass samples especially when you go for trace elements because your

glass already contains a lot of chemistry that will end up in your sample but it's not

in your sample it's coming from the sample vial.

So a plastic material is the ideal stuff for chemistry sampling if you are endowed just

go for HDPE high density polyethylene or polypropylene sampling vials.

We take two vials today one is for the positively charged for the cations and one is for the

negatively charged for the N ions because they are typically analyzed on two different

devices by two different techniques later in the laboratory.

We unpack our syringe.

We fill gently our syringe with our sample water.

You can use the syringe several times you do not need to use a new syringe on the next

sampling location however make sure that you pre flush you have to clean your sample or

at least contaminate the sample your syringe with your sample that you are then filling

into your sampling vial.

So we are pre cleaning our syringe put our disc filter on oh sorry first we of course

we have to fill again our syringe gently with our sampling water put on the disc filter

make sure it sticks to the syringe and then pre flush the filter with a few ml and then

open your vials and in fact there is nothing spectacular in taking chemistry samples.

If you wish you can also pre flush your sampling vials

and then gently fill your two vials or falcon tubes in this case.

Cap it you should avoid a too large headspace.

If you are going to transport the vials for example by air cargo then you might leave

a small gap just to allow for some expansion of the water in case of a strong temperature

change but these are filled without any headspace.

You label it with your sample ID of course yeah so where is the sample from and you name

one for the cations and one for the anions.

So we have one cation and one anion sample.

If you are going to take these samples around with you for a couple of hours and days during

a field campaign I advise you to acidify one of these vials and you have to acidify then

the cation the vial for the positively charged ions to reduce or to lower the pH value by

concentrated nitric acid.

This will lower the pH down to a pH of two and this avoids the sticking of the cations

to the surface of the vial and it stabilizes the sample until you have transported it to

the lab.

And as a final measure of security I would say you can take some parafilm which is a

wax foil available from most laboratories and you can just put the wax foil around the

cap to avoid an unwanted opening of the cap by mechanical force or if you are going to