Finally, all the reports employed the analysis by means of LC-MS/MS. Concretely, Fourier transform (LC-FTMS), single quadrupole ion trap (QTrap), triple
quadrupole (QqQ), and time of flight (LC-QToF-MS) mass spectrometers were
employed for the detection of analytes of interest (Table 7).
8 Separation and Detection
It is widely known nowadays that pharmaceuticals are present in solid environmental
and food matrices, such as soil and crops, at very low concentrations (few μg/kg up
to g/kg). Advances in chromatography techniques and mass spectrometry instruments have facilitated the separation and the detection of pharmaceuticals extracted
from any kind of environmental and food matrices even at trace levels. Despite this,
these samples are analytically very difficult to analyze because of their complexity
and their numerous components that interfere with the detection of pharmaceutical
products.
Liquid chromatography (LC) and gas chromatography (GC) are both used for
pharmaceutical analysis, depending on their polarity and/or volatility. Chromatography techniques used for soil and crops are reported in Tables 2, 3, 4, 5, and 6.
However, liquid chromatography (LC) is most widely used since most pharmaceutical products have high polarity and low volatility. Furthermore, whenever GC is
used, the extracted pharmaceutical products need an additional derivatization procedure and/or the replacement with a GC-compatible organic solvent before their
injection.
BSTFA
(N,O-bis(trimethylsilyl)trifluoroacetamide)
+
TMS
(trimethylsilyl) are the derivatization reagents commonly used [54, 80, 81, 85,
92]. Aside from the fact that most pharmaceutical products are polar and
non-volatile, some are also thermolabile, such as tetracycline [31, 195], making
the derivatization step an essential phase for their detection. In general, organic
reactions, such as methylation, silylation, and acetylation, undergo the derivatization
of the hydroxyl and carboxyl groups of pharmaceutical products. However, in this
way, a further step is added to the analytical protocol, which can affect the efficiency
of the method due to the loss of analytes, incomplete reactions, or the introduction of
unwanted contaminants [195]. Therefore, LC has an advantage over GC since no
derivatization step is necessary. However, it should be remembered that GC is
convenient, suitable for routine analysis, and less subject to matrix effects [54, 196].
LC and GC are basically coupled to mass spectrometers (MS). In addition, several
studies have used LC coupled with ultraviolet (UV), fluorescence (FLD), or diode
array (DAD) detectors for the detection of a few numbers of pharmaceutical products
[68, 78, 162]. However, lower detection and quantification limits were obtained
compared to LC coupled to MS. Furthermore, the high-resolution mass spectrometry
(HRMS) allows to perform a non-target analysis of pharmaceutical, as well as their
environmental transformation products, or even the products of the metabolism
without compromising the sensitivity of the analysis [196].
476
R. Manasfi et al.
quadrupole (QqQ), and time of flight (LC-QToF-MS) mass spectrometers were
employed for the detection of analytes of interest (Table 7).
8 Separation and Detection
It is widely known nowadays that pharmaceuticals are present in solid environmental
and food matrices, such as soil and crops, at very low concentrations (few μg/kg up
to g/kg). Advances in chromatography techniques and mass spectrometry instruments have facilitated the separation and the detection of pharmaceuticals extracted
from any kind of environmental and food matrices even at trace levels. Despite this,
these samples are analytically very difficult to analyze because of their complexity
and their numerous components that interfere with the detection of pharmaceutical
products.
Liquid chromatography (LC) and gas chromatography (GC) are both used for
pharmaceutical analysis, depending on their polarity and/or volatility. Chromatography techniques used for soil and crops are reported in Tables 2, 3, 4, 5, and 6.
However, liquid chromatography (LC) is most widely used since most pharmaceutical products have high polarity and low volatility. Furthermore, whenever GC is
used, the extracted pharmaceutical products need an additional derivatization procedure and/or the replacement with a GC-compatible organic solvent before their
injection.
BSTFA
(N,O-bis(trimethylsilyl)trifluoroacetamide)
+
TMS
(trimethylsilyl) are the derivatization reagents commonly used [54, 80, 81, 85,
92]. Aside from the fact that most pharmaceutical products are polar and
non-volatile, some are also thermolabile, such as tetracycline [31, 195], making
the derivatization step an essential phase for their detection. In general, organic
reactions, such as methylation, silylation, and acetylation, undergo the derivatization
of the hydroxyl and carboxyl groups of pharmaceutical products. However, in this
way, a further step is added to the analytical protocol, which can affect the efficiency
of the method due to the loss of analytes, incomplete reactions, or the introduction of
unwanted contaminants [195]. Therefore, LC has an advantage over GC since no
derivatization step is necessary. However, it should be remembered that GC is
convenient, suitable for routine analysis, and less subject to matrix effects [54, 196].
LC and GC are basically coupled to mass spectrometers (MS). In addition, several
studies have used LC coupled with ultraviolet (UV), fluorescence (FLD), or diode
array (DAD) detectors for the detection of a few numbers of pharmaceutical products
[68, 78, 162]. However, lower detection and quantification limits were obtained
compared to LC coupled to MS. Furthermore, the high-resolution mass spectrometry
(HRMS) allows to perform a non-target analysis of pharmaceutical, as well as their
environmental transformation products, or even the products of the metabolism
without compromising the sensitivity of the analysis [196].
476
R. Manasfi et al.