Keywords Enantiomeric separation, Environmental analysis, Food analysis, Gas
chromatography, Mass spectrometry, Pyrethroids
1 Introduction
Pyrethroid insecticides were developed to replace organophosphorus pesticides,
which were largely used in the past three decades and were demonstrated to have
potentially toxic effects on humans [1]. Pyrethroids are the synthetic analogues of
pyrethrins which were developed as pesticides from the extracts of dried and
powdered flower heads of Chrysanthemum cinerariaefolium. Because of the rapidly
decomposition of pyrethrins in the presence of light, pyrethroids were developed to
increase stability to light and residence time in the environment, maintaining the
effective insecticidal activity of the pyrethrins [2]. Pyrethroids are persistent compounds with high hydrophobicity (log Kow 5.7–7.6) [3, 4] and very low water
solubility (a few lg/L), so they preferentially adsorbed to solid particles [5]. They can
persist in the environment for few months before being degraded [6, 7] and can be
bioaccumulated in aquatic organisms [8, 9] and humans [10, 11]. Aquatic organisms
such as invertebrates and fish are extremely sensitive to the neurotoxic effect of these
insecticides. In fish (e.g., bluegill and lake trout), LC50 values were estimated to be
less than 1 g/L [12]. Regarding their effects on humans, reversible symptoms of
poisoning and suppressive effects on the immune system have been reported
[13]. Moreover, pyrethroids have been included in a list of suspected endocrinedisrupting chemicals [14]. The development of analytical methods for the analysis of
pyrethroid insecticides is very important, considering their large usage for domestic
and agricultural pest control applications and their presence in the environment and
in food and their capacity to be bioaccumulated by organisms. Table 1 shows a list of
pyrethroids usually determined in environmental, biological, and food samples. In
addition to conventional extraction methods (e.g., liquid-liquid extraction or solidphase extraction for liquid samples and sonication or pressurized liquid extraction
for solid samples), new methods simple and rapid with reduced reagent use
have been recently developed for the extraction of pyrethroids from environmental,
biological, and food samples. Examples of these are the liquid-liquid
microextraction based on solidification of floating organic droplet used for liquid
samples or QuEChERS (stands for quick, easy, cheap, effective, rugged, and safe)
method applied to solid samples. Following extraction and purification, the detection
and quantification of pyrethroids can be performed by gas chromatography
(GC) combined with electron capture detection (ECD) or mass spectrometry (MS),
as well as by liquid chromatography (LC). This chapter describes the various aspects
of sample preparation, extraction, purification, and instrumental analysis of synthetic
pyrethroids in different environmental and food matrices mainly focusing on the
development made in the last 15 years.
18
M. L. Feo
chromatography, Mass spectrometry, Pyrethroids
1 Introduction
Pyrethroid insecticides were developed to replace organophosphorus pesticides,
which were largely used in the past three decades and were demonstrated to have
potentially toxic effects on humans [1]. Pyrethroids are the synthetic analogues of
pyrethrins which were developed as pesticides from the extracts of dried and
powdered flower heads of Chrysanthemum cinerariaefolium. Because of the rapidly
decomposition of pyrethrins in the presence of light, pyrethroids were developed to
increase stability to light and residence time in the environment, maintaining the
effective insecticidal activity of the pyrethrins [2]. Pyrethroids are persistent compounds with high hydrophobicity (log Kow 5.7–7.6) [3, 4] and very low water
solubility (a few lg/L), so they preferentially adsorbed to solid particles [5]. They can
persist in the environment for few months before being degraded [6, 7] and can be
bioaccumulated in aquatic organisms [8, 9] and humans [10, 11]. Aquatic organisms
such as invertebrates and fish are extremely sensitive to the neurotoxic effect of these
insecticides. In fish (e.g., bluegill and lake trout), LC50 values were estimated to be
less than 1 g/L [12]. Regarding their effects on humans, reversible symptoms of
poisoning and suppressive effects on the immune system have been reported
[13]. Moreover, pyrethroids have been included in a list of suspected endocrinedisrupting chemicals [14]. The development of analytical methods for the analysis of
pyrethroid insecticides is very important, considering their large usage for domestic
and agricultural pest control applications and their presence in the environment and
in food and their capacity to be bioaccumulated by organisms. Table 1 shows a list of
pyrethroids usually determined in environmental, biological, and food samples. In
addition to conventional extraction methods (e.g., liquid-liquid extraction or solidphase extraction for liquid samples and sonication or pressurized liquid extraction
for solid samples), new methods simple and rapid with reduced reagent use
have been recently developed for the extraction of pyrethroids from environmental,
biological, and food samples. Examples of these are the liquid-liquid
microextraction based on solidification of floating organic droplet used for liquid
samples or QuEChERS (stands for quick, easy, cheap, effective, rugged, and safe)
method applied to solid samples. Following extraction and purification, the detection
and quantification of pyrethroids can be performed by gas chromatography
(GC) combined with electron capture detection (ECD) or mass spectrometry (MS),
as well as by liquid chromatography (LC). This chapter describes the various aspects
of sample preparation, extraction, purification, and instrumental analysis of synthetic
pyrethroids in different environmental and food matrices mainly focusing on the
development made in the last 15 years.
18
M. L. Feo