Chemical Standards needed.

[jacobavera]

Hi guys I have a bunch of chemicals I need to test to see if they are still good.they came with the DR/2 spectrophotometer.
when I started I figured they would all be bad. I have had two good tests & 1 unknown. They give colors for good or bad and mines neither one.
Does anybody know if there are sets of .? chemical standards?
heres an example: Fluoride standard solution 500mL concentration:0.8 mg/L F- $17 for 4 bottles.
Thanks
ps even though I have a Dr/2 I'm really a beginner, so please forgive me if I say something stupid.

[thompson]

Standard solutions are simply solutions made up to very high accuracy, usually using reagent-grade or better chemicals, and usually standardized to several significant figures. Depending on how good your balance and volumetric glassware are, you can make up these solutions yourself to very high precision.