Mycoremediation of Synthetic Dyes: An Insight into the Mechanism, Process Optimization and Reactor Design - Microbial Degradation of Synthetic Dyes in Wastewaters - page 7

Table 3 Advantages and limitations of various analytical techniques (modi ed after Fern á ndez
et al. 2010 )
Analytical
techniques

Advantages Limitations

Separation tech-
niques (HPLC,
GCMS etc.)

High selectivity Analysis time can be high

Degradation byproducts can be
accurately identi ed with an MS
detector

Samples normally need to be
pretreated

Organic solvents need to be used

Spectroscopic tech-
niques (UV-vis,
FTIR etc.)

Low analysis time Low selectivity

Sample pre-treatment is simple or
not necessary

The presence of interferents
(degradation byproducts) can
lead to erroneous results

Dyes can be determined on the
catalyst surface (SERS)

Expensive deuterated solvents
need to be used (NMR)

Chemometrics can be used to
simultaneously identify and
quantify several dyes and
intermediates

Microscopic
techniques

Short analysis time Sample preparation required for

electron microscopy

Any morphological changes
occurring on microbial biomass
can be visually seen

Few techniques are only quali-
tative (except EDX)

Enzymatic
techniques

Highly selective Applicable in only live process

Do not vary with microbe or
substrate

Dependent on nutritional
conditions
Individual assay required for
each enzyme

following two principles: disappearance of the substrate or the appearance of the
new product, essentially a colored compound which can be quanti ed by spec-

troscopic techniques.
Table 4 shows various studies which adopted described analytical techniques in
examining thedye removal process. Recently, use of high performance capillary
electrophoresis has gained a lot of importance (Zhao et al. 2007 ; Lu et al. 2008 )in
determining the dye and their intermediates or by-products (which have ionic
character). During dye degradation process, the dye peak undergoes a continuous
change. Initially, it decreases and then certain new peaks appear which later on
disappear due to the formation of small undetectable compounds. Use of a MS
detector helps in a more accurate identi cation of such compounds. For the study of