Hach-Lange ISENH418103 User Manual - Manual (Page 13)

Percent recovery
Use the following formula to calculate the percent recovery when the sample volume is
25 mL:
E = (C x V
1
) / V
2
R = (A / (E + S)) x 100
• S = mg/L of Ammonium in sample (before spike)
• C = concentration of standard used for spiking (mg/L)
• V
1
= spike volume (mL)
• V
2
= spike volume (mL) + 25 mL sample volume
• E = expected concentration of spike (mg/L)
• R = percent recovery
• A = actual reading on meter after spike (mg/L Ammonium)
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