Does anyone have recommendations for a good pH meter to use for titration? Preferably something that gives pretty quick and accurate readings, can withstand being dunked through some toulene or limonene for a little while, doesn't need a ton of maintenance, and won't break the bank. I'm sick of inaccurate pH paper. What do you use? Thanks!

glass electrodes will withstand solvents like toluene and limonene, but there is no reason to ever put a pH electrode in a nonpolar solvent, because hydronium ions do not dissociate in them.

I've always worked with Thermo Orion (mine is a 230A), Beckman, Corning, and VMR meters. all work well.

PH meter

It appears in that thread that a certain member has some major knowledge about ph meters

EDIT: WOW, that was strange! You are on it benz! lol

I have this one



On ebay they list 10$ less, like 90$.
Non lab grade but kitchen alchemist friendly alternative.
I like the replaceable electrode, pen's usually do not.
Long chord and slim electrode to hang in the pot while having 1 hand free for stirring and other hand for adding acid/base.
Very stable calibration, after months the 7.00 went to 6.90 only, I store the electrode in calibration fluid 7.00 (official electrode store liquid is not cheap and for now I can't imagine doing better)
I think the 9 volt block battery supply does a good job, my previous pen had button batteries that tend to sink voltage after initial startup, so had to wait for stability each time before a reading was done. Not with this one, fast stable working readily after after ON.
I've access to plenty of lab calibration fluids and could see the little white provided bottles failing to concernable accuracy after a while they've been opened/stored.
It's a glass electrode inside a plastic protecting tube that saves the day on a bumpy occasion.

Thanks guys, that's helpful. @Benzyme, the thought wasn't to try to measure pH of the nonpolar layer (I know better than that), but to just be able to stick the electrode into the jar, through the nonpolar layer, and get a reading of the aqueous solution underneath without having to pull it off and measure separately. This would save a bit of time, but perhaps it's not worth the step up in price from something like this...

that looks proprietary, vs the one you have. like mine, yours likely has a universal connection (BNC) for electrodes. this is ideal, for obvious reasons.

*edit* wait...is that a 1/8" input for calibration? is there a BNC connection on top?

Ive found papers to be accurate enough for cacti titrations

If you refer to mine, yes BNC for electrode, and 1/8" connector jack for the temp probe. Works without inserted temp probe as well, just no temp-to-pH correction then, but this correction not an issue if everything happens at room temp.

Calibration with small scewdriver on the front, 2 points.

Mind that you're already at 70$ with that, replaceable electrode yes, but check price of such electrode. I had such a meter once, broke electrode, and a new electrode for that type was expensive. The electrodes with BNC connector are much cheaper to find.

I've good papers,this type:
In some cases they really do miss by 1 pH, on other occasions they're spot on. I guess if you always use them in same type of solution at same temp they're reliable. For roughly acid-basing rue I always use them papers because precision is not really necessary, and its fast easy checking. For something finer I reach in a nerdy style for the digital meter

I haven't messed with papers in years, but i use my meter every week now that I have a gardenia plant.

thermo orion 230A with cole parmer glass electrode (autoclaveable).
jees' first pic shows a typical working setup... pH 4 and 7 cal buffers, and electrode in storage solution.