Simple technique for preparing any strength volumetric solution,.

 

Good evening all  

This post is for the new trainee and 1-2 years experienced Pharma QC analysts, to understand about ppm level concentration solution preparation. 

I will start sharing the analytical concepts with the very  basic level, to understand easily, so that you understand the concept and utilize in the routine analysis practice. 

Kindly suggest me on which analytical topic you need the basic information. 

Todays topic is ppm level solution preparation 

ppm level  solution preparation 

ppm = parts per million

ppm is a term used in chemistry to denote a very, very low concentration of a solution. One gram in 1000 ml is 1000 ppm and one thousandth of a gram (0.001g) in 1000 ml is one ppm.

Example-1 

 1gm in 1000mL is 1000ppm 

let me explain 

1g x 1000000(for converting in to ppm)           =  1000ppm   

         1000ppm

=1000000 is for converting in to ppm

= 1000mL dilution factor 

=1g substance to be dissolved for which 1000ppm solution to be prepared 

Example -2 

(0.001g) in 1000 ml is one ppm.

0.001g x 1000000(for converting in to ppm)           =  1ppm   

         1000ppm

=1000000 is for converting in to ppm

= 1000mL 

=0.001g 

       

Converting ppm in to % 

Also 1000ppm =  0.1% 

 1000(ppm)  x 100(for%)           =  0.1%

         1000000( ppm to %)

Now please find how to prepare 1000ppm Na standard solution using sodium chloride 

Some different type of example if 1000ppm Na (Sodium ) standard solution to be prepared using sodium chloride.

Molecular weight for the Nacl = 58.44g.

At. wt. of Na = 23

1g Na in relation to FW of salt = 58.44 / 23 = 2.542g.

Hence, weigh  2.542g of NaCl and dissolve in 1 liter volume of diluent to make a 1000 ppm Na standard.



From an acidic radical of the salt :

To make 1000ppm of the phosphate standard using the salt KH₂PO₄

e.g. Make a 1000 ppm phosphate standard using the salt KH₂PO₄

FW of KH₂PO₄ salt = 136.09

FW of radical PO₄ = 95

1g PO₄ in relation to FW of salt = 136.09 / 95 = 1.432g.

Hence, weigh  1.432g KH₂PO₄ and dissolve in 1 liter volume to make a 1000 ppm PO₄ standard.

In next topic we will  discuss about impurity standard preparation w.r.to  test concentration.

Thanks