limited to nitrate; spectroscopic measurement of nitrate is listed as a standard method
[11]. Especially for trace contaminations, where individual substances concentrations are requested at the low ppb or even ppt levels, the current generation of
spectrophotometric devices is lacking in sensitivity when applied in a water matrix.
Typical sensitivities for each technology type are given in Table 2.
7 Outlook
Smart water systems are expected to revolutionise the water industry. Through the
combination of information from various sources at all levels in the water system,
more effective management will become possible. This will help reduce costs,
increase safety and ensure that infrastructure will be able to cope with changing
demands, such as urbanisation, climate change and decentralisation. In this datadriven approach, sensors are an essential link in the chain, as they provide the raw
Table 2 (continued)
Method
Generic properties
Advantages
Disadvantages
independent of the nature
of the analyte-plasma
releases all atoms from
their chemical environment. Use, e.g. to detect
total concentration of an
element, such as P, As or
Cr
• Sensitivity varies
with element and with
sample matrix
• Provides elemental
composition of the sample, no information on
chemical composition
Refractive
index
• Measures physical
property of sample,
which is responsive to
the chemical makeup of
the sample
• ppm level sensitivity
• Generic, sensitive to
all types of chemicals,
both organic and inorganic
• Good for monitoring
stability/variability of the
sample composition
• Consistent sensitivity,
with only minor variations between different
types of substances
• Generic, not possible
to identify the cause for a
change in signal
Image
analysis
• Analysis of combinations of optical properties of particles
• Targeting samples
with cell concentrations
in the 1,000/mL or
higher
• Culture- and reagentfree analysis of microbiological properties, such
as total cell counts
• Combinations of optical properties sometimes
allow for classification of
cells
• Only suited for analysis of particles
• Time-consuming
when analysing properties of individual cells
(e.g. flow cytometry)
Spectroscopic Methods for Online Water Quality Monitoring
311
[11]. Especially for trace contaminations, where individual substances concentrations are requested at the low ppb or even ppt levels, the current generation of
spectrophotometric devices is lacking in sensitivity when applied in a water matrix.
Typical sensitivities for each technology type are given in Table 2.
7 Outlook
Smart water systems are expected to revolutionise the water industry. Through the
combination of information from various sources at all levels in the water system,
more effective management will become possible. This will help reduce costs,
increase safety and ensure that infrastructure will be able to cope with changing
demands, such as urbanisation, climate change and decentralisation. In this datadriven approach, sensors are an essential link in the chain, as they provide the raw
Table 2 (continued)
Method
Generic properties
Advantages
Disadvantages
independent of the nature
of the analyte-plasma
releases all atoms from
their chemical environment. Use, e.g. to detect
total concentration of an
element, such as P, As or
Cr
• Sensitivity varies
with element and with
sample matrix
• Provides elemental
composition of the sample, no information on
chemical composition
Refractive
index
• Measures physical
property of sample,
which is responsive to
the chemical makeup of
the sample
• ppm level sensitivity
• Generic, sensitive to
all types of chemicals,
both organic and inorganic
• Good for monitoring
stability/variability of the
sample composition
• Consistent sensitivity,
with only minor variations between different
types of substances
• Generic, not possible
to identify the cause for a
change in signal
Image
analysis
• Analysis of combinations of optical properties of particles
• Targeting samples
with cell concentrations
in the 1,000/mL or
higher
• Culture- and reagentfree analysis of microbiological properties, such
as total cell counts
• Combinations of optical properties sometimes
allow for classification of
cells
• Only suited for analysis of particles
• Time-consuming
when analysing properties of individual cells
(e.g. flow cytometry)
Spectroscopic Methods for Online Water Quality Monitoring
311