Limits...
Using sequential injection analysis to improve system and data reliability of online methods: determination of ammonium and phosphate in coastal waters.

Frank C, Schroeder F - J Autom Methods Manag Chem (2007)

Bottom Line: These measures are advantageous during method development and validation and can be used to verify the system performance on a regular base to reduce the amount of erroneous results.No changes in the flow system are necessary and the sample throughput is only slightly reduced.Results from a campaign in summer 2005 are shown.

View Article: PubMed Central - PubMed

Affiliation: GKSS Research Centre, Institute for Coastal Research, Max-Planck-Strasse, 21502 Geesthacht, Germany.

ABSTRACT
This article summarises the advantages of the sequential injection analysis (SIA) for the online determination of nutrients in coastal waters. It concentrates on techniques to improve the reliability of the gained data by continuously monitoring one or more standards and on the advantages of online standard additions and offline determination of manually collected samples with the online SIA system. These measures are advantageous during method development and validation and can be used to verify the system performance on a regular base to reduce the amount of erroneous results. No changes in the flow system are necessary and the sample throughput is only slightly reduced. These techniques have been applied to a SIA system which is able to simultaneously determine ammonium and phosphate at a rate of more than 100 samples per hour each and detection limits (3sigma) of 0.06 muM and 0.05 muM. Results from a campaign in summer 2005 are shown.

No MeSH data available.


Phosphate data in μM calculated from the valuesindicated in Figure 4. Additionally, offline samples(diamonds) are integrated into the diagram. The arrows point tothe theoretically corresponding online samples with the samerestrictions as explained in Figure 8.
© Copyright Policy - open-access
Related In: Results  -  Collection


getmorefigures.php?uid=PMC1828606&req=5

Figure 9: Phosphate data in μM calculated from the valuesindicated in Figure 4. Additionally, offline samples(diamonds) are integrated into the diagram. The arrows point tothe theoretically corresponding online samples with the samerestrictions as explained in Figure 8.

Mentions: The third and last step of such a review would be the comparisonof manually collected and pretreated samples with the onlinesample. However, due to the assumed inhomogeneity of the waterbody and the proven inertness of the sampling and samplepretreatment system (a circular pump and a cross-flow filter), themanual samples were taken from the filtrate stream as indicated inFigure 7. These seven minutes pooled samples wereintegrated into the SIA system using a former unused valve port.The results of these determinations are shown together with theonline data in the Figures 8 and 9. Together with the legitimate assumption that neither the pumping nor thefiltration did have a that significant effect on the sample, itcan be proposed that there may occur high variations in theconcentration of ammonium in the open sea.


Using sequential injection analysis to improve system and data reliability of online methods: determination of ammonium and phosphate in coastal waters.

Frank C, Schroeder F - J Autom Methods Manag Chem (2007)

Phosphate data in μM calculated from the valuesindicated in Figure 4. Additionally, offline samples(diamonds) are integrated into the diagram. The arrows point tothe theoretically corresponding online samples with the samerestrictions as explained in Figure 8.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC1828606&req=5

Figure 9: Phosphate data in μM calculated from the valuesindicated in Figure 4. Additionally, offline samples(diamonds) are integrated into the diagram. The arrows point tothe theoretically corresponding online samples with the samerestrictions as explained in Figure 8.
Mentions: The third and last step of such a review would be the comparisonof manually collected and pretreated samples with the onlinesample. However, due to the assumed inhomogeneity of the waterbody and the proven inertness of the sampling and samplepretreatment system (a circular pump and a cross-flow filter), themanual samples were taken from the filtrate stream as indicated inFigure 7. These seven minutes pooled samples wereintegrated into the SIA system using a former unused valve port.The results of these determinations are shown together with theonline data in the Figures 8 and 9. Together with the legitimate assumption that neither the pumping nor thefiltration did have a that significant effect on the sample, itcan be proposed that there may occur high variations in theconcentration of ammonium in the open sea.

Bottom Line: These measures are advantageous during method development and validation and can be used to verify the system performance on a regular base to reduce the amount of erroneous results.No changes in the flow system are necessary and the sample throughput is only slightly reduced.Results from a campaign in summer 2005 are shown.

View Article: PubMed Central - PubMed

Affiliation: GKSS Research Centre, Institute for Coastal Research, Max-Planck-Strasse, 21502 Geesthacht, Germany.

ABSTRACT
This article summarises the advantages of the sequential injection analysis (SIA) for the online determination of nutrients in coastal waters. It concentrates on techniques to improve the reliability of the gained data by continuously monitoring one or more standards and on the advantages of online standard additions and offline determination of manually collected samples with the online SIA system. These measures are advantageous during method development and validation and can be used to verify the system performance on a regular base to reduce the amount of erroneous results. No changes in the flow system are necessary and the sample throughput is only slightly reduced. These techniques have been applied to a SIA system which is able to simultaneously determine ammonium and phosphate at a rate of more than 100 samples per hour each and detection limits (3sigma) of 0.06 muM and 0.05 muM. Results from a campaign in summer 2005 are shown.

No MeSH data available.