Chemistry Reference
In-Depth Information
Determination of Triazole Fungicides in
Fruits and Vegetables by Liquid
Chromatography-Mass Spectrometry (LC/MS)
Nor Haslinda Hanim Bt Khalil and Tan Guan Huat
Additional information is available at the end of the chapter
http://dx.doi.org/10.5772/55306
1. Introduction
Triazole pesticides derivatives represent the most important category of fungicides that
have excellent protective, curative and eradicant power towards a wide spectrum of crop
diseases [1]. The fungicide group, demethylation inhibitors (DMI), which contain the
triazole fungicides, was introduced in the mid-1970s. These fungicides are highly effective
against many different fungal diseases, especially powdery mildews, rusts, and many leaf-
spotting fungi. [2].
The number of pesticides registered for use increases every year and many pesticides that
have been banned for health reasons are also still being used illegally. And introduction of
new pesticides in the field of residue analysis also cause the laboratories involved in the
analysis to face more challenging task. This leads to the development of many multi-residue
methods by various researchers [3-7].
In the past, pesticides and their degradation products, which are generally thermolabile,
non-volatile and exhibit medium to high polarity have been analysed using GC with specific
detectors such as ECD, NPD and FPD [8-12]. Due to the drawbacks of the separation
techniques such as sensitivity, insufficient number of analytes that can be analysed and the
need for confirmation either with different column polarity or detectors, GC/MS has become
the primary approach to analyse all classes of GC-amenable pesticides [3, 13-14]. Later,
HPLC combined with a diode array UV detector was established as a complementary
technique to GC to analyse
pesticides and their degradation products [15].
However it is not
sufficient to use only the UV spectrum for identification of the analytes. R
obust atmospheric
pressure ionization (API) ion source designs, which consist of electrospray ionization (ESI)
and atmospheric pressure chemical ionization (APCI) were developed and very powerful
