Phosphorus, Reactive (Orthophosphate)
Phosphorus, Reactive (Orthophosphate)
Page 4 of 6
PhosphorusReac_TNT_Other_PV3_Eng_Ody.fm
8. After completing the sequence, touch Graph to view the best-fit line through
the standard additions data points, accounting for matrix interferences. Touch
View: Fit, then select Ideal Line and touch OK to view the relationship between
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
1.0-mg/L PO
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Phosphate Standard Solution, touch Options on the current
program menu. Touch
Standard Adjust.
3. Touch
On. Touch Adjust to accept the displayed concentration (the value
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
OK.
Touch
Adjust.
Method Performance
Precision
Standard: 3.00 mg/L PO
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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
See Section 3.4.5 Sensitivity on page 44 for more information.
Summary of Method
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.
Program 95% Confidence Limits of Distribution
535 2.89–3.11 mg/L PO
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Portion of Curve ∆Abs ∆Concentration
Entire range 0.010 0.06 mg/L PO
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