Detection of gliclazide in aqueous samples using liquid chromatography/time-of-flight/mass spectrometry

The big challenge for the detection of pharmaceutical residues in water samples is the type of ionization mode in terms of positive or negative ionization which plays an important role to identify and quantify the analytes using liquid chromatography/mass spectrometry. An analytical method was applied to analysis of gliclazide (diabetic drug) in surface water and wastewater from sewage treatment plants and hospitals. The proposed analytical method allows simultaneous isolation and concentration procedure using solid phase extraction (Oasis HLB) prior to separation using high-performance liquid chromatography. The detection and confirmation was achieved by applying time-of-flight analyzer. The limits of quantification were as low as 1.4 ng/L (deionized water), 4 ng/L (surface water), 27 ng/L (hospital influent), 10 ng/L (hospital effluent), 6 ng/L (sewage treatment plant effluent) and 21 ng/L (sewage treatment plant influent), respectively. On average, good recoveries of higher than 87% were obtained for gliclazide in the studied samples. The proposed method successfully determined and quantified gliclazide in surface water and wastewater. The results showed that gliclazide is a persistent compound in sewage treatment effluents as well as in the recipient rivers. Gliclazide was detected in all samples and the highest concentration was 130 ng/L in influent of sewage treatment plant

Development and validation of a comprehensive solid-phase extraction method followed by LC-TOF/MS for the analysis of eighteen pharmaceuticals in influent and effluent of sewage treatment plants

The scarcity of data about the occurrence of pharmaceuticals in water bodies in Malaysia prompted us to develop a suitable analytical method to address this issue. We therefore developed a method based on solid-phase extraction combined with liquid chromatography–time of flight/mass spectrometry (SPE-LC-TOF/MS) for the analysis of sixteen prescribed and two nonprescribed pharmaceuticals that are potentially present in water samples. The levels of these pharmaceuticals, which were among the top 50 pharmaceuticals consumed in Malaysia during the period 2011–2014, in influent and effluent of five sewage treatment plants (STPs) in Bangi, Malaysia, were then analyzed using the developed method. All of the pharmaceuticals were separated chromatographically using a 5 μm, 2.1 mm × 250 mm C18 column at a flow rate of 0.3 mL/min. Limits of quantification (LOQs) were 0.3–8.2 ng/L, 6.5–89 ng/L, and 11.1–93.8 ng/L in deionized water (DIW), STP effluent, and STP influent, respectively, for most of the pharmaceuticals. Recoveries were 51–108%, 52–118%, and 80–107% from the STP influent, STP effluent, and DIW, respectively, for most of the pharmaceuticals. The matrix effect was also evaluated. The signals from carbamazepine, diclofenac sodium, and mefenamic acid were found to be completely suppressed in the STP influent. The signals from other compounds were found to be influenced by matrix effects more strongly in STP influent (enhancement or suppression of signal ≤180%) than in effluent (≤94%). The signal from prednisolone was greatly enhanced in the STP influent, indicating a matrix effect of −134%. Twelve pharmaceuticals were frequently detected in all five STPs, and caffeine, prazosin, and theophylline presented the highest concentrations among all the pharmaceuticals monitored: up to 7611, 550, and 319 ng/L in the STP influent, respectively. To the best of our knowledge, this is the first time that prazosin has been detected in a water matrix in Malaysia

Different mobile phases and elution programs were optimized to separate seven basic pharmaceuticals using LC-QTOF/MS

Analysis of pharmaceuticals is very important, because these compounds have broad spectrum of chemicals and consider environmental emerging issue, so in this article several mobile phases and elution programs were optimized to separate 7 pharmaceutically active compounds with different therapeutic classes of pharmaceuticals using LC-QTOF/MS. A simple, reproducible and sensitive method for the separation of these compounds were provided using LC-QTOF/MS by gradient elution with a flow rate of 0.3 ml/min. The retention factor, selectivity, tailing factor and resolution were calculated for all compounds. Linearity for all compounds was satisfied in terms of R2>0.99.Limit of detection and limit of quantitation for all compounds were (0.9-5 μg/l) and (3.2-16.6 μg/l) respectively

Electro-transformation of mefenamic acid drug: a case study of kinetics, transformation products, and toxicity

Poor removal of many pharmaceuticals and personal care products in sewage treatment plants leads to their discharge into the receiving waters, where they may cause negative effects for aquatic environment and organisms. In this study, electrochemical removal process has been used as alternative method for removal of mefenamic acid (MEF). For our knowledge, removal of MEF using electrochemical process has not been reported yet. Effects of initial concentration of mefenamic acid, sodium chloride (NaCl), and applied voltage were evaluated for improvement of the efficiency of electrochemical treatment process and to understand how much electric energy was consumed in this process. Removal percentage (R%) was ranged between 44 and 97%, depending on the operating parameters except for 0.1 g NaCl which was 9.1%. Consumption energy was 0.224 Wh/mg after 50 min at 2 mg/L of mefenamic acid, 0.5 g NaCl, and 5 V. High consumption energy (0.433 Wh/mg) was observed using high applied voltage of 7 V. Investigation and elucidation of the transformation products were provided by Bruker software dataAnalysis using liquid chromatography-time of flight mass spectrometry. Seven chlorinated and two non-chlorinated transformation products were investigated after 20 min of electrochemical treatment. However, all transformation products (TPs) were eliminated after 140 min. For the assessment of the toxicity, it was impacted by the formation of transformation products especially between 20 and 60 min then the inhibition percentage of E. coli bacteria was decreased after 80 min to be the lowest value

Can anaerobic intermediate stages affect the biotransformation and sorption of pharmaceutical compounds?

Batch experiment was conducted to investigate if anaerobic intermediate stages can affect bio-transformation and sorption performance of selected pharmaceutical compounds (stimulant caffeine (CAF), anti-diabetic drug gliclazide (GCZ) and anti-hypertensive drug prazosin (PRZ)). The outcome revealed that CAF was removed solely via biotransformation and followed the methanogenic pathway. Sorption was significant during the fermentation stage for hydrophobic GCZ and PRZ although both compounds continued to biotransform in the later stage of incubation. While more than 95% removal of all compounds was achieved after 30 d of incubation under anaerobic mesophilic condition, further incubation to Day 90 resulted in re-occurrences of GCZ and PRZ in the aqueous and solid phase. Biotransformation of hydrophilic and hydrophobic compounds could not be represented in the same kinetic model considering sorption and retransformation dis-played significant effect to the model. This study also reported the first removal of GCZ and PRZ under anaerobic condition

The fate of prazosin and levonorgestrel after electrochemical degradation process: Monitoring by-products using LC-TOF/MS

Prazosin (PRZ) and levonorgestrel (LNG) are widely used as an anti-disease drugs due to their biological activity in the human body. The frequent detection of these compounds in water samples requires alternative technologies for the removal of both compounds. After electrochemical degradation of PRZ and LNG, the parent compounds could be completely removed after treatment, but the identification and characterization of by-products are necessary as well. In this study, the effects of NaCl concentration and applied voltage were investigated during the electrochemical degradation process. The results revealed that the increase of NaCl concentration and applied voltage could promote the generation of hypochlorite OCl− and then enhance the degradation of PRZ and LNG. After initial study, 6 V and 0.2 g NaCl were selected for further experiments (96% and 99% removal of PRZ and LNG after 40 min, respectively). Energy consumption was also evaluated and calculated for PRZ and LNG at 3, 6 and 8 V. Solid phase extraction (SPE) method plays an important role in enhancing the detection limit of by-products. Furthermore, characterization and identification of chlorinated and non-chlorinated by-products were conducted using an accurate liquid chromatography-time of flight/mass spectrometry LC-TOF/MS instrument. The monitoring of products during the electrochemical degradation process was performed at 6 V and 0.2 g NaCl in a 50 mL solution. The results indicated that two chlorinated products were formed during the electrochemical process. The toxicity of by-products toward E. coli bacteria was investigated at 37°C and 20 hr incubation time

A review of the biological treatment of leachate: Available technologies and future requirements for the circular economy implementation

Leachate, which refers to dark-colored toxic wastewater generated from landfills, has become an issue of environmental concern, posing a threat to soil, surface water, and groundwater quality, thereby negatively affecting humans’ health. Therefore, it is necessary to select the most appropriate leachate treatment methods considering its complex properties. Among several treatment processes available for this purpose, the biological treatment process is notably effective at removing pollutants and also relatively affordable to operate. Its application to leachate treatment has received much attention in recent years. This study summarizes the leachate characteristics and the methods of leachate treatment with a focus on biological approaches, either aerobic or anaerobic. In addition, this paper concisely discusses the effectiveness and the factors influencing the performance of each treatment technology in case of organics, nutrients, and other pollutants removal. The findings of this paper are expected to provide a deeper insight into the future research and development of leachate treatment, especially the biological treatments concerning the circular economy