## 1 Introduction
Besides, the knowledge of their concentration is essential as a starting point to apply more advanced treatments to improve their removal and, consequently, minimize their environmental risk [32]. Under this scenario, analytical chemistry plays an essential part in providing high-quality information by applying two different approaches: (i) target analysis and (ii) screening methods for the determination of non-target or unknown compounds (degradation products). Both of the approaches demand highly sophisticated techniques that enable the implementation of sensitive and selective methods to provide accurate data regarding the identification, confirmation, and quantification of compounds [33]. In this context, the analytical challenges, mainly in quantitative analysis, are focused on developing and validating new materials, strategies, and procedures to quickly meet the requirements for selectivity, sensitivity, speed, and green methods. Because of the constantly updating of international standards, guidelines, and recommendations, constant innovation is mandatory in both the pre-treatment procedures and analytical equipment to obtain reliable, true, and reproducible data [34; 35]. Gas chromatography (GC) or liquid chromatography (LC) coupled to mass spectrometry (MS) or tandem mass spectrometry (MS/MS) are advanced methods that can determine target compounds to the nanogram per liter level or lower and they are commonly applied for the detection of PhACs in different water [36; 37] and solid matrices, such as sediments, sludges, and biota [38; 39; 40]. Because of the polar characteristics of PhACs, the liquid chromatography is the most used [41; 42; 43; 44]. Nevertheless, since the late 80s, liquid chromatography-mass spectrometry (LC-MS) has rapidly grown in popularity as a technique for environmental control. Common mass analyzers applied in target analysis of these compounds are triple quadrupoles (QqQ) [45; 46], ion-trag (IT) [38], and quadrupole-linear ion trap (QLIT-MS/MS) [37; 47]. On the field of liquid chromatography coupled to tandem mass spectrometry, ultra-performance liquid chromatography (UPLC) has enabled the development of more sensitive, fast, and environmentally friendly methods for pharmaceuticals [10; 48; 49; 50]. Improvements in the identification capability for target compounds have also been achieved by the introduction of high-resolution mass spectrometry (HRMS). The time-of-flight (TOF), quadrupole-TOF (QTOF), and Orbitrap-based mass spectrometry in combination with chromatographic techniques have resulted in a valuable tool, not only for qualitative, but also quantitative, analysis of target compounds [33]. [PERSON] et al. (2010) have described the advantage of using a QTOF analyzer in the identification, confirmation,and quantification of almost 400 contaminants (mainly pesticides and pharmaceuticals) in surface water and wastewater [51]. The analysis of transformation products has also become an important issue in environmental chemistry, as it has been found that they may be more toxic and/or persistent than the parent compounds, thus representing a higher risk to the environment and human health [52; 53; 54]. In this area, LC or GC coupled to HRMS has been widely applied in the identification of transformation products, with time-of-flight (TOF), quadrupole-TOF (QTOF), and Orbitrap mass spectrometers increasing in use. These techniques were used in the study of the behavior of PhACs, the identification of their transformation or degradation products in wastewaters, natural waters, and drinking waters [55; 56; 51]. Owing to the large-scale dilution of these contaminants in water sources (natural waters) or due to the matrix complexity, a preliminary sample preparation technique for concentration or/and clean-up is mandatory, such as liquid-liquid extraction (LLE) [57], solid-phase extraction (SPE) [58; 59; 60; 10; 27], solid-phase microextraction (SPME) [27; 28], or stir bar sorptive extraction (SBSE) [61].