EN ISO 15681-2:2004

Foreword
Introduction
1 Scope
2 Normative references
3 Interferences
   3.1 General interferences
   3.2 Interferences in the determination of total-P
4 Principle
   4.1 Determination of orthophosphate
   4.2 Total phosphorus with manual digestion
   4.3 Total phosphorus with integral UV digestion and
       hydrolysis
5 Reagents
6 Apparatus
   6.1 Continuous-flow analysis (CFA)
   6.2 Additional apparatus
   6.3 Additional apparatus for the determination of total
       phosphorus after integral digestion
7 Sampling and sample preparation
8 Procedure
   8.1 Preparation for analysis
   8.2 Instrument performance check
   8.3 Reagent blank check
   8.4 Calibration
   8.5 Check of UV digestion and hydrolysis for total P
       determination
   8.6 Measurement
   8.7 Closing down the system
9 Calculation of results
10 Expression of results
11 Test report
Annex A (informative) Examples of a CFA system
Annex B (informative) Precision and accuracy
Annex C (informative) Determination of orthophosphate-P and
                      total-P by CFA and tin(II) chloride
                      reduction
Bibliography

ISO 15681-2:2003 specifies CFA methods for the determination of orthophosphate in the mass concentration range from 0,01 mg/l to 1,00 mg/l P, and total phosphorus in the mass concentration range from 0,10 mg/l to 10,0 mg/l P. The method includes the digestion of organic phosphorus compounds and the hydrolysis of inorganic polyphosphate compounds, performed either manually as described in ISO 6878 or with an integrated UV digestion and hydrolysis unit.ISO 15681-2:2003 is applicable to various types of water (such as ground, drinking, surface, leachate and waste water). The range of application may be changed by varying the operating conditions.This method is also applicable to the analysis of seawater, but with changes in sensitivity, by adaptation of the carrier and calibration solutions to the salinity of the samples.