Rinse aid for glassware??

[~megz~]

Hello all,

My Head Teacher has asked that I wash all the glassware and rinse in 'rinse aid in preparation for a titration prac... I have bought some good old home brand rinse aid which I think is designed for use in dishwashers. I don't have a dishwasher, so was planning to rinse in the sink. Does anyone know how much I should dilute it by? I don't want it too strong, but also don't want it to not work!

Thanks in advance,
Meg

[Sassi]

When I clean glassware for titration I do it as per normal protocol, but then I rinse it in distilled water. I dont know about using rinse aid for dishwashers, but it kinda seems to defeat the purpose a bit. What does everyone else think???

Sass

[Sassi]

Sorry I should clarify that a bit more...

Because titration is an analytical technique, the proper method must be used if you are going to get meaningful quantitative results. In general you will always want to use the following procedures:
1. Make sure that everything is clean. Proper cleaning technique for glassware is generally to:
• wash with hot soapy water, using a brush
• rinse several times with tap water, until all traces of soap have been removed
• rinse several times with portions of distilled or de-ionized water (it is better to wash 5 times with 10 mL of water each time, than once with 50 mL of water!)
• either allow the glassware to air dry (which will take at least a day, unless you have a drying oven), or rinse two or three times with the solution that will go in the container

[lada]

Yes, i do the same. After washing, I rinse with tap water a few times and then with distilled. Let it dry overnight.
The rinsing aid seems a bit much, do you know what is in it? It could make it worse.
lada

[~megz~]

Thanks Sassi and Lada for your replies,

I kind of figured the same thing - that Rinse Aid might interfere with the result: but when I asked my HT he said that he wants them rinsed in Rinse Aid so that they 'flow evenly' or something. I've washed and rinsed them all really thoroughly, so it's just the final stage

Anyway - I think I'll just use the tiniest splash of it in some distilled water, and let them dry overnight - then I can say I did what was asked!

Thanks again!

Megs

[Ocker]

If I need them Quick I sometimes rinse in Metho and they dry almost straight away with no residue

[Tina]

My husband works in a lab where they do work with micronutrients and all glassware has to be scrupulously clean. They soak in dilute HCL, then rinse in distilled water 4 times, then soak in 'decon' (a strong base), then rinse in distilled water 4 times again! I dont suggest that!

At this level in high school they are looking at technique, not results. It is part of the students education to think of possible sources of experimental error.

Rinsing with the solution they are about to use, before they begin a titration, should be an essential part of the student's learning to do a titration themselves and you should just have to wash them up normally as per the protocol.

Cheers
Tina

[~megz~]

Well, I rinsed them in the tiniest amount of rinse aid in water, then rinsed each one three or four times in distilled water, set them out to dry, and went home feeling very satisfied with my efforts...

BUT - alas, this morning when I arrived, I realised that the place I had put them all to dry has the sun on it in the mornings, and they are all wet with condensation I was so upset with myself. I was thinking "I've ruined the prac". So with trepidation I took them up to the teacher, and he said...

"doesn't matter, they have to rinse them anyway." LOL! All that stress for nothing!

I can feel my people pleasing urges draining away by the second... Pretty soon I'll be a hardened, devil-may-care, not-my-problem kind of girl

Thanks everyone for your help, anyway

[Robb]

Hi All, be careful as rinse aid is alkaline and will defeat the purpose of Titrimetric Analysis.

Just out of pure curiosity.

Cheers,

Robb.....