Method development for detection and removal of multi-class pharmaceutical residues in hospital wastewater / Husam I. S. Kafeenah

Sensitive detection method is basic to detect and monitor pharmaceutical waste in an environment. Simultaneous determination of multi-classes pharmaceutical compounds with different chemical properties at trace level is desirable in obtaining reliable data within a short time and low cost with good accuracy. In the first part of this study, a new detection method was developed for multi-classes pharmaceuticals in tap water and wastewater samples using solid phase extraction based on disk for clean-up and pre-concentration, prior to the analysis by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Ten types pharmaceuticals of different polarity and chemical properties (acetaminophen, caffeine, diclofenac, ibuprofen, mefenamic acid, metformin, nifedipine, perindopril, salbutamol and simvastatin) were studied. Therefore, electrospray ionisation (ESI) in positive and negative ionisation modes was employed simultaneously for the UPLC-MS/MS analysis of these acidic, neutral and basic pharmaceutical compounds. The feature of the current method was in using a disk solid phase extraction (SPE) for single pre-treatment of polar, semi-polar and nonpolar pharmaceutical analytes. The performance of disk solid phase extraction and cartridge solid phase extraction were compared. Disk SPE gave higher sensitivity and recovery and consumed less analysis time and solvent. The method validation shows good absolute recovery ranged from 70 % to 122 % of tap water, 62 % to 121 % for effluent wastewater and 62 % to 121 % for influent wastewater except for metformin, which the absolute recovery values were approximately 48 % for all sample types. The results indicated that the new developed method was successfully applied to all the targeted pharmaceuticals in three different matrices, including tap water, effluent, and influent wastewater. The method shows high sensitivity and good precision as compared to corresponding methods. Most of the targeted pharmaceuticals were detected in the influent and effluent wastewater obtained from hospital treatment plant at different concentrations. The result also showed a variation in the treatment efficiencies for the hospital treatment plant from one compound to another with the removed rate ranged from 0 % to 99 %. In the second part of this study, a new green approach for the removal of the multi-class pharmaceutical residues from the wastewater in a batch process using two different activated carbons (a homemade activated carbon prepared from Artocarpus integer fruit peels and commercial activated carbon) was investigated. The results obtained from the batch removal experiments proved that the method succeeded to eliminate all the targeted pharmaceutical residues from the effluents wastewater at high percentages of removal (95 %-100 %). An adsorption kinetic test showed rapid adsorption using both activated carbons for most of the pharmaceuticals within the first 20 min. The adsorption kinetic process of the two adsorbents for all the pharmaceuticals is categorized as a pseudo-second order

Effect of Mobile Phase pH on the Electrospray Ionization Efficiency and Qualitative Analysis of Pharmaceuticals in ESI + LC-MS/MS

The effect of mobile phase pH on positive ionization process and retention time of nine pharmaceuticals on ultra-performance liquid chromatography-electrospray-tandem mass spectrometry (LC-MS/MS) was discussed. The effective use of high and low mobile phase pH in LC-MS/MS qualitative analyses method was also evaluated by comparing the instrument detection limit, quantification limit, precision, linearity and signal to noise (S/N) under low and high mobile phase pH. In this work, six mobile phase pH that ranged between pH 2 and pH 10 were used to evaluate the effect of the mobile phase pH changes on the ionization process in electrospray ionization. Results revealed that high mobile phase pH ionized more pharmaceuticals molecules and gave a higher signal than low mobile phase pH in positive ionization mode. The results proved that ammonium ion was better as a proton donor in high pH mobile phase than the hydronium ion in acidic mobile phase. The results revealed that the qualitative LC-MS/MS analyses method by using high mobile phase pH has better performance for most analytes in terms of sensitivity, precision, linearity and S/N than the low mobile phase pH. © 2019 The Author(s). Published by Oxford University Press. All rights reserved

UPLC-MS/MS screening method for simultaneous identification and characterisation of acidic and basic pharmaceuticals

<p>A new screening method was developed for the simultaneous determination of seven acidic and basic pharmaceuticals by the ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) utilising triple quadrupole mass spectrometry as a detector. The target pharmaceutical compounds of interest in this work belong to different classes of pharmaceutical group with different physico-chemical properties. Both the positive and negative ionisation modes (dual ionisation mode) in electrospray ionisation (ESI) were used simultaneously. Unlike previous studies, the performance of the dual ionisation mode was compared with the positive and negative ionisation modes individually in terms of analysis time and sensitivity. Results indicate that the developed screening method was successfully applied for the simultaneous determination of the acidic and basic pharmaceutical compounds. Using dual ionisation mode reduced the analyses time while still maintaining sensitivity and quality of the analytical result. The new method was implemented in detecting the targeted analyte in a real sample of wastewater. The instrument detection limit (IDL) was as low as 9.7 fg, indicating a high sensitivity as compared to the corresponding methods. The precision of the instrument was calculated as the relative standard deviation (RSD) ranging from 1.4 to 11.0%. The limit of quantification (LOQ) for the method was over the range 0.77–177 ng L⁻¹ and 1.05–100 ng L⁻¹ for the influent and effluent wastewater, respectively.</p