Hach DR2400 Manual page 650

Phosphorus, Reactive (Orthophosphate)
Method Performance
Summary of Method
Phosphorus, Reactive (Orthophosphate)
Page 4 of 6
8. After completing the sequence, touch
the standard additions data points, accounting for matrix interferences. Touch
, then select
View: Fit
the sample spikes and the "Ideal Line" of 100% recovery.
See Section 3.2.2 Standard Additions on page 32 for more information.
Standard Solution Method
1. Use a 1.0-mg/L phosphate standard solution in place of the sample. Perform
the procedure as describe above.
2. To adjust the calibration curve using the reading obtained with the
3–
1.0-mg/L PO Phosphate Standard Solution, touch
4
program menu. Touch
3. Touch . Touch
On Adjust
depends on the selected chemical form). If an alternate concentration is used,
touch the number in the box to enter the actual concentration, then touch
Touch .
Adjust
Precision
Standard: 3.00 mg/L PO
Program
535
See Section 3.4.3 Precision on page 44 for more information, or if the standard
concentration did not fall within the specified range.
Sensitivity
Portion of Curve
Entire range
See Section 3.4.5 Sensitivity on page 44 for more information.
Orthophosphate reacts with molybdate in an acid medium to produce a mixed
phosphate/molybdate complex. Ascorbic acid then reduces the complex, giving
an intense molybdenum blue color. Test results are measured at 880 nm.
Graph
and touch
Ideal Line OK
.
Standard Adjust
to accept the displayed concentration (the value
3–
4
95% Confidence Limits of Distribution
2.89–3.11 mg/L PO
∆Abs
0.010
to view the best-fit line through
to view the relationship between
on the current
Options
3–
4
∆Concentration
0.06 mg/L PO
PhosphorusReac_TNT_Other_PV3_Eng_Ody.fm
.
OK
3–
4