Hach Micro Dist - Trapping Solution Concentration Equivalency

35
Cyanide–1
To 50 mL of sample is also added 2 mL of a 510 g MgCl
2
· 6 H
2
O/L
(2.5 M) solution. This gives a concentration of:
8.6 Calculations Showing Equivalency of Concentrations of Trapping
Solution
Equivalency of Micro Dist Method Cyanide–1 and in USEPA
Method 335.2.
8.6.1 Micro Dist Method Cyanide–1
In the Micro Dist Method, 1.5 mL of 1.0 M NaOH becomes 6.0 mL
solution after distillation and dilution to the mark:
1.0 M NaOH x (1.5 mL / 6.0 mL) = 0.25 M NaOH
8.6.2 USEPA Method 335.2
In the macro distillation, 50 mL of 1.25 M NaOH becomes 250 mL
solution after distillation and dilution to the mark:
1.25 M NaOH x (50 mL / 250 mL) = 0.25 M NaOH
USEPA Method 335.4
In the macro distillation, 50 mL of 0.25 M NaOH remains undiluted.
2.5 M MgCl
2
6 H
2
O⋅ 2 mL× 57 mL total()⁄
0.088 M MgCl
2
6 H
2
O⋅()=