Dropper bottle teats

[Lyn]

I very rarely (perhaps never) send out the glass dropper bottles with the glass and rubber pipettes. I have lots of empty bottles stored in trays but these do not get used. Over the years I seem to have trained the science teachers (senior) to accept that the chemicals now come in plastic dropper bottles. Trained the junior teachers years ago. It is so much easier.
Question: Is this wrong?

[bigmack]

I floated the idea of the plastic ones and was told no way , our mob would squirt each other with them .....maybe ....maybe not ....I'll never find out .

[Merilyn1]

I've found they are a bit trickier to use, easy to go a bit heavy handed. Also had some that the lids split after a while, so the chemical would come flying out the side when the students squeezed the bottle. That was a very long time ago, don't know if they have improved (the bottles, not the students) - the last few schools I've been at have only had the glass bottles.

[bigmack]

RE: Silicone rubber teats

Anyway. come in today and went to top up the 1M sodium hydroxide ones for a prac and discovered that several of them have started to "become one " with the dropper bottle requiring peeling off .................. It's possible that the kids just screwed the lids on really tight .

Well it does appear that this was the problem.
So long as I check the droppers when they come back and make sure they are not over tight , they seem to work fine . 5 months now .
The ones with alcohol in them like phenolphalien which would normally deteriorate very quickly seem just fine .

I will order some more .

[bigmack]

Update on the Silicone rubber teats .They hate Acid

After 7 months on HCl 1M and they are disintegrating . Ones on NHO3 1M no better .

Silicone teats.jpg

Hates Acid.jpg

However they seem to be fairing OK with Alcohol based indicators such as Phenolthalien and universal Indicator which the Red Rubber ones didn't like .
The Sodium Hydroxide also seems happy in the silicone Rubber . As do the Silver Nitrate.

So It's looking like I will go back to Red Rubber for acids and use the Silicone Rubber for the rest .

[Merilyn1]

Thanks for the update, Richard. I'm not sure if even these ones are still available, might need to get onto MTA who have bought Serrata to see if they can help us out. If we can use the black ones on a lot of solutions, it will keep us out of trouble for a few years.
Otherwise, no luck from anyone being able to supply the red rubber teats on their own. There is a labbie on the ASET email list in NSW who has been trying to source them, but without success.

[Lyn]

Are the red rubber teats available on the Westlab site not the right size for what you require? Seems only logical to check what our lab tech site benefactor has to offer.

[Merilyn1]

Don't think they are the right ones Lyn. Just looked at the photo on the website of "Teats Rubber". They don't have the rim around the bottom that holds them into the white plastic cap of the dropper assembly. I don't usually buy from the benefactor, regardless.

[macca]

I don't have any dropper bottles anymore all in stull bottles no more contamination, less spills and very little deterioration. Silver nitrate bottles are covered in foil been using like that for 8-9 years now not a problem. Iodine in amber regent bottles kid use disposable droppers.

So much easier, 125ml bottles so don't need to be filled as often.

Have never had a problem with kids squirting, our teachers had the same thoughts.

[MariaQ]

Yep I discovered this yesterday!

[bigmack]

I'm not sure if even these ones are still available, might need to get onto MTA who have bought Serrata to see if they can help us out. If we can use the black ones on a lot of solutions, it will keep us out of trouble for a few years.

The old Serrata link now brings you to MTA ....seems like they only changed over a few days ago . But yes MTA have them ( the black silicone ones )

Interestingly the MTA ( Serrata) web catalog seems much easier to use than the old Serrata one

[bigmack]

I don't have any dropper bottles anymore all in stull bottles no more contamination, less spills and very little deterioration. Silver nitrate bottles are covered in foil been using like that for 8-9 years now not a problem. Iodine in amber regent bottles kid use disposable droppers.

Macca , how do the labels stay on the stull bottles ? I 'm just thinking they would be soft and squeezy and labels wouldn't stick to well

[Merilyn1]

I have bought some things from MTA - their printed catalogue was HUGE, but not a lot of science stuff. I guess Serrata will fill a gap. The things I bought from MTA (some embedded specimens) were very good quality. I might try the black silicon ones next time I'm ordering.
Thanks again, Richard, for the update.

[Prima]

I don't have any dropper bottles anymore all in stull bottles no more contamination, less spills and very little deterioration. Silver nitrate bottles are covered in foil been using like that for 8-9 years now not a problem. Iodine in amber regent bottles kid use disposable droppers.

Macca , how do the labels stay on the stull bottles ? I 'm just thinking they would be soft and squeezy and labels wouldn't stick to well

I've bought two different types of "Stuhl" bottles. One was good quality, firm plastic. The other was very thin, soft and over-flexible. I use the cheaper version for detergent, oil, etc, and keep the better quality ones for chemicals. I can't remember who I bought them from, sorry!

[macca]

Hi Prima & Bigmack,

I purchase mine from Hains educational only buy the 125ml you can buy extra caps if need be. I don't have any trouble with the labels (Risk Assess), use laser printer on A4 paper and just use sticky tape over the top.

Students and teachers are all aware and taught from Yr7 that all lids are to be closed before returning to prep room.

[bigmack]

I'm not sure if even these ones are still available, might need to get onto MTA who have bought Serrata to see if they can help us out. If we can use the black ones on a lot of solutions, it will keep us out of trouble for a few years.

The old Serrata link now brings you to MTA ....seems like they only changed over a few days ago . But yes MTA have them ( the black silicone ones )

Interestingly the MTA ( Serrata) web catalog seems much easier to use than the old Serrata one

Note: $4.50 it for a 10 pack not each
https://www.teaching.com.au/search?acti ... pe=product