ATLGIRL
Bluelighter
I need help figuring out something for my job that is bothering me. We have a method derived from USP231/Method II testing for heavy metals. Our method is different in the Ammonium Acetate buffer preparation at a pH of 3.5. It has been already registered with the FDA as part of the initial approval so the method can't be modified now.
In the method, I have to use 25% HCL. It doesn't say if it's v/v or v/w but because it is USP, you always assume that they mean weight per volume.
So as you are already know, the most concentrated HCL (12.1 Normaliy) is 36-37%. So I have to go from (36-37%) to 25% W/V. I can't just use the dilution M1V1=M2V2. I have to use the density of HCL and calculate it that way. I tried to see if Fischer makes 25% W/V HCL but all I can find is 25% v/v so I have to calculate it and make it myself.
Please help me figuring out how many mLs I can use from (concentrated HCL (12.1 Normaliy) is 36-37%) to make a total of 500 mLs of 25% HCL V/W. Everyone at my company makes it different and it frustrates me. The internet has conflicting answers so it would be great if someone can help and be confident.
In the method, I have to use 25% HCL. It doesn't say if it's v/v or v/w but because it is USP, you always assume that they mean weight per volume.
So as you are already know, the most concentrated HCL (12.1 Normaliy) is 36-37%. So I have to go from (36-37%) to 25% W/V. I can't just use the dilution M1V1=M2V2. I have to use the density of HCL and calculate it that way. I tried to see if Fischer makes 25% W/V HCL but all I can find is 25% v/v so I have to calculate it and make it myself.
Please help me figuring out how many mLs I can use from (concentrated HCL (12.1 Normaliy) is 36-37%) to make a total of 500 mLs of 25% HCL V/W. Everyone at my company makes it different and it frustrates me. The internet has conflicting answers so it would be great if someone can help and be confident.
