Tech Tips:

Preparing Dilute Standard Solutions

Standard solutions should be prepared to create a calibration curve. Standard solutions can be prepared by diluting a known concentrated standard by specified amounts. A chart or computer spreadsheet can be created to determine the proper dilutions. Use volumetric flasks and pipets for all dilutions.

In Column A- Record the maximum concentration of test as determined by the range and path length.
In Column B- Record the percent of the maximum concentration the standard solution will be.
In Column C- Calculate the final concentration of the diluted standard solutions by multiplying the maximum concentration (In Column A) by the % of maximum concentration divided by 100. (C = A x (B/100)).
In Column D- Record the final volume of the diluted sample (i.e. volume of volumetric flask).
In Column E- Record the concentration of the original standard.
In Column F- Calculate the milliliters of original standard required (C x (D/E) = F).

Sample Chart:
A	B	C = A x (B/100)	D	E	F = C x (D/E)
Maximum concentration of test	% of Maximum Concentration	Final Concentration of Diluted Standard	Volume of Standard	Concentration of Original Standard	mL of Original Standard Required
10.0 ppm	90	9.0 ppm	100 mL	1000 ppm	0.90 mL
10.0 ppm	70	7.0 ppm	100 mL	1000 ppm	0.70 mL
10.0 ppm	50	5.0 ppm	100 mL	1000 ppm	0.50 mL
10.0 ppm	30	3.0 ppm	100 mL	1000 ppm	0.30 mL
10.0 ppm	10	1.0 ppm	100 mL	1000 ppm	0.10 mL
10.0 ppm	0	0 ppm	100 mL	1000 ppm	0 mL

LaMotte Company