Chemical Forums
Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: stdacet on September 20, 2015, 12:57:25 AM
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I am in search of a standard method for acid washing of glassware specifically prior to heavy metal analysis.
According to AOAC, it requires soaking glassware in (1:1) HCl for two hours. Once prepared, for how long such acid solution can be used for repeated washing/ soaking continuously ?
As it will require large volumes of acid, I am searching for any other method. Generally, I can find method with 10 % or 20 % HCl or HNO3, but can anyone refer a standard method.
Thanks
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Off hand, you can use any method that works .
You probably want to claim you're conforming to a standard, so you'll want to apply the standard method, and claim in your results that you're following the method. So there's that.
As to what other method you can use, or how long 1:1 HCl is good or what quantity of glassware can be cleaned, or how dirty the glassware can be and the cleaning still be good the answer is pretty much the same ... as long as it works.
I'm no expert on this particular topic but you can informally pay particular attention to your blanks, or you can formally conduct a cleaning validation: pick the analyate you're most sensitive to, gak up some glassware, possibly drying it onto the glassware, execute the cleaning procedure to the standard procedure you want to execute it (freshly prepared 1:1 HCl, no older than 1 day, 2 days old, whatever.) Then evaluate that the cleaning process works adequetely, write it up, file it, and tell everyone -- "Round here, this is how its done." And if they don't like it, they can re-validate with their process.
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Thanks, validation of the procedure will really work.