Hi Last year there were a few reports in the chemical press (e.g. https://doi.org/10.1039/D1SC02708E, and references therein) of studies of glass catalysing reactions - it seems that it isn’t as benign as one might imagine. Of course, this will not be news to the old chemical hands on this BB...
Harry > On 31 Jan 2022, at 10:09, Artem Evdokimov <artem.evdoki...@gmail.com> wrote: > > Interesting note - and a reminder that alkaline solutions are tricky :) By > personal preference, HDPE bottles are probably the best for storing strongly > alkaline solutions (XLPE also is very good, but harder to get lab-grade > bottles). > > Here's a handy chart for plastic vs stuff resistance. Note that HDPE is "E" > whereas PC (polycarbonate) is "N". > > https://www.calpaclab.com/chemical-compatibility-charts/ > > Glass is not recommended for alkali storage, although there are some glass > products that have A1 or better alkali resistance rating. They can get pretty > esoteric, especially if one requires near-complete passivity towards strongly > alkaline solutions. > > Artem > > - Cosmic Cats approve of this message > > > On Sun, Jan 30, 2022 at 1:02 PM Edward Berry <ber...@upstate.edu> wrote: > After using the same reagents for the Lowry assay and seeing the color yield > in the standard curve gradually decreasing year by year, we decided to make > new reagents last year. Sure enough the color yield was restored, but in the > next assay a few weeks later the blank was unusually high. after a month the > blank read nearly 1 AU. > > The problem was, we stored the alkaline reagent (NaOH + Na2CO3)in a > polycarbonate bottle. I like polycarbonate because it is transparent and hard > like glass, but lighter and less breakable. But polycarbonate is a polyester > of Bis-phenol A with carbonic acid. Apparently the high pH slowly hydrolyzes > the ester linkages, or the plastic retains some monomers that slowly leach > out, and (duh!) bis-phenol A gives a positive reaction with the > Folin-Ciocalto phenol reagent. > > ######################################################################## > > To unsubscribe from the CCP4BB list, click the following link: > https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 > > This message was issued to members of www.jiscmail.ac.uk/CCP4BB, a mailing > list hosted by www.jiscmail.ac.uk, terms & conditions are available at > https://www.jiscmail.ac.uk/policyandsecurity/ > > To unsubscribe from the CCP4BB list, click the following link: > https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 > ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 This message was issued to members of www.jiscmail.ac.uk/CCP4BB, a mailing list hosted by www.jiscmail.ac.uk, terms & conditions are available at https://www.jiscmail.ac.uk/policyandsecurity/
