(QTRAP or QLIT) [61] are used as tandem MS/MS for pharmaceutical analysis from
soil and crops. However, MS/MS systems offer high sensitivity, selectivity, and
precision and lower limits of detection and quantification, particularly in the analysis
of complex solid matrices. In other words, hybrid mass spectrometers are built by
combining two different analyzers in a single instrument and provide more information on the sample in shorter analysis times, therefore an easy differentiation
between target analytes and interfering components of the matrix. Jacobsen and
coworker [58] used QqQ for the analysis of chlortetracycline, oxytetracycline,
sulfadiazine, erythromycin, and tylosin (TYL) and its degradation products,
TYL A, B, C, and D, from soil, obtaining low detection and quantification limits
(from 0.6 to 5.6 g/kg and from 25.7 to 73.9 g/kg, respectively). Martínez-Piernas and
coworkers [155] used QTOF for the analysis of carbamazepine transformation
products from lettuce obtaining detection limits less than 3 ng/g in dry weight
samples.
In addition, IT analyzers have the ability to perform multiple compound fragmentation steps (MS
n ) and to trap fragment ions resulting in full-scan spectra with
high sensitivity. Barron and coworkers [55] used LC-ESI-ion trap-MS in single and
tandem MS modes, and they obtained detection limits below 20 ng/g for 20 pharmaceuticals out of 27 from soil, reporting poorer sensitivity for paracetamol,
salbutamol, caffeine, pravastatin, indomethacin, and clotrimazole. However, they
assumed that this poor sensitivity might be due to their low % recovery. The
combination of IT with quadrupole analyzers (QTRAP or QLIT) offers the robustness of a QqQ with the full scan and high sensitivity of IT. Low method detection
limits were obtained with García-Galán and coworkers [61] using this instrument,
ranging from 0.03 to 2.23 ng/g, for sulfonamide extraction from soil. However, for a
better selectivity, QTOF and Orbitrap are the chosen instrument. They provide highresolution and accurate masses for parent and fragment ions in full-scan spectra.
Accordingly, they remove the interfering signals, making it easier to identify the
non-target compounds in complex environmental and food matrices
[155, 200]. Orbitrap was used by Chitescu and coworkers [74], for the extraction
of oxytetracycline, sulfamethoxazole, and ketoconazole from grass, obtaining detection limits lower than 10 μg/kg.
The methodologies managed in full-scan mode or single ion monitoring (SIM)
with a single quadrupole showed the need for a highly efficient cleaning phase. On
the other hand, the use of multiple reaction monitoring (MRM) mode with MS/MS
systems offers maximum selectivity with a reduced matrix effect. It allows identification by monitoring the target compound and usually the most abundant transitions
(product ions, generally two) [197].
Finally, to deal with the evaluation of the matrix effects, which can cause an
enhancement or reduction of the analyte response, most of the studies used isotopically labeled compounds. However, not all deuterated compounds associated with
each analyte are available for purchase or are sometimes very expensive.
478
R. Manasfi et al.
soil and crops. However, MS/MS systems offer high sensitivity, selectivity, and
precision and lower limits of detection and quantification, particularly in the analysis
of complex solid matrices. In other words, hybrid mass spectrometers are built by
combining two different analyzers in a single instrument and provide more information on the sample in shorter analysis times, therefore an easy differentiation
between target analytes and interfering components of the matrix. Jacobsen and
coworker [58] used QqQ for the analysis of chlortetracycline, oxytetracycline,
sulfadiazine, erythromycin, and tylosin (TYL) and its degradation products,
TYL A, B, C, and D, from soil, obtaining low detection and quantification limits
(from 0.6 to 5.6 g/kg and from 25.7 to 73.9 g/kg, respectively). Martínez-Piernas and
coworkers [155] used QTOF for the analysis of carbamazepine transformation
products from lettuce obtaining detection limits less than 3 ng/g in dry weight
samples.
In addition, IT analyzers have the ability to perform multiple compound fragmentation steps (MS
n ) and to trap fragment ions resulting in full-scan spectra with
high sensitivity. Barron and coworkers [55] used LC-ESI-ion trap-MS in single and
tandem MS modes, and they obtained detection limits below 20 ng/g for 20 pharmaceuticals out of 27 from soil, reporting poorer sensitivity for paracetamol,
salbutamol, caffeine, pravastatin, indomethacin, and clotrimazole. However, they
assumed that this poor sensitivity might be due to their low % recovery. The
combination of IT with quadrupole analyzers (QTRAP or QLIT) offers the robustness of a QqQ with the full scan and high sensitivity of IT. Low method detection
limits were obtained with García-Galán and coworkers [61] using this instrument,
ranging from 0.03 to 2.23 ng/g, for sulfonamide extraction from soil. However, for a
better selectivity, QTOF and Orbitrap are the chosen instrument. They provide highresolution and accurate masses for parent and fragment ions in full-scan spectra.
Accordingly, they remove the interfering signals, making it easier to identify the
non-target compounds in complex environmental and food matrices
[155, 200]. Orbitrap was used by Chitescu and coworkers [74], for the extraction
of oxytetracycline, sulfamethoxazole, and ketoconazole from grass, obtaining detection limits lower than 10 μg/kg.
The methodologies managed in full-scan mode or single ion monitoring (SIM)
with a single quadrupole showed the need for a highly efficient cleaning phase. On
the other hand, the use of multiple reaction monitoring (MRM) mode with MS/MS
systems offers maximum selectivity with a reduced matrix effect. It allows identification by monitoring the target compound and usually the most abundant transitions
(product ions, generally two) [197].
Finally, to deal with the evaluation of the matrix effects, which can cause an
enhancement or reduction of the analyte response, most of the studies used isotopically labeled compounds. However, not all deuterated compounds associated with
each analyte are available for purchase or are sometimes very expensive.
478
R. Manasfi et al.