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.

Disk solid-phase extraction of multi-class pharmaceutical residues in tap water and hospital wastewater, prior to ultra-performance liquid chromatographic-tandem mass spectrometry (UPLC-MS/MS) analyses.

In this work, a new clean-up and pre-concentration method based on disk solid-phase extraction (SPE) was developed to determine multi-class pharmaceutical residues covering a wide range of polarities (log K ow values from -0.5 to 5.1) in water systems, prior to ultra-performance liquid chromatographic-tandem mass spectrometry (UPLC-MS/MS) analyses. Electrospray ionisation in positive and negative modes was used for the simultaneous determination of both acidic and basic pharmaceuticals. The performances of disk SPE and cartridge SPE were compared. The targeted pharmaceutical compounds list included bronchodilators, antidiabetic drugs, antihypertensive drugs, a lipid-lowering agent, analgesics, and anti-inflammatory drugs. Based on our results, the disk SPE demonstrated a higher sensitivity and recovery value and less analysis time as compared to the cartridge SPE method. The limits of detection (LOD) for the new method ranged from 0.02-3.2 ng L-1, 0.02-3.1 ng L-1 and 0.02-4.7 ng L-1 for tap, effluent and influent wastewater, respectively. The method's absolute recovery values ranged from 70% to 122% for tap water, 62% to 121% for effluent wastewater and 62% to 121% for influent wastewater, except for metformin in which the absolute recovery value was approximately 48% for all samples. Intra-day precision for tap water, effluent and influent wastewater ranged from 3-12%, 4-9% and 2-8%, respectively. The method developed was applied for the determination of targeted pharmaceuticals in tap, effluent, and influent wastewater from one hospital treatment plant in Malaysia. The results revealed that the highest concentrations of certain pharmaceuticals were up to 49 424 ng L-1 (acetaminophen) and 1763 ng L-1 (caffeine) in the influent and effluent wastewater, respectively. The results also showed a variation in the treatment efficiencies for the hospital treatment plant from one compound to another. Nevertheless, the removal efficiencies ranged from 0-99%.

In vitro antiplasmodial activity, macronutrients and trace metals in the medicinal plants: Phyllanthus spp. and Alpinia conchigera Griff.

An antiplasmodial screening of Phyllanthus debilis and Phyllanthus urinaria was carried out. The medicinal plants were extracted and evaluated for in vitro antiplasmodial activity against D10 (chloroquine-sensitive, CQS) and Gombak A (chloroquine-resistant, CQR) strains of Plasmodium falciparum. The methanolic crudes from the soxhlet extraction were active against both strains however, P. urinaria (IC50 8.9 µg/ml with CQR strain) exhibited better anti-malarial activity compared to P. debilis (IC50 12.2 µg/ml with CQR strain). Furthermore, the methanolic crude of P. urinaria obtained by the cold extraction has good anti-malarial activity towards CQS (IC50 4.1 µg/ml). The concentration of macronutrients (calcium and magnesium) and trace metals (copper, manganese, iron and zinc) from three Phyllanthus species i.e. P. debilis Klein ex Wild., Phyllanthus niruri L., P. urinaria L. and Alpinia conchigera Griff. were determined using microwave digestion method and analyzed by Flame Atomic Absorption Spectroscopy. Standard Reference Material 1547 (peach leaves) was used to validate the method throughout this study. The recovery values were in the range of 80% to 120% which were in very good agreement with the certified values. The three Phyllanthus species and leaves of A. conchigera showed the highest concentration of calcium compared to other metals and macronutrients studied. The significant presence of all the important macronutrients and trace metals which are essential for human health and well-being substantiate their use medicinally in traditional practices.

In vitro antiplasmodial activity, macronutrients and trace metals in the medicinal plants: Phyllanthus spp. and Alpinia conchigera Griff

An antiplasmodial screening of Phyllanthus debilis and Phyllanthus urinaria was carried out. The medicinal plants were extracted and evaluated for in vitro antiplasmodial activity against D10 (chloroquine-sensitive, CQS) and Gombak A (chloroquine-resistant, CQR) strains of Plasmodium falciparum. The methanolic crudes from the soxhlet extraction were active against both strains however, P. urinaria (IC50 8.9 μg/ml with CQR strain) exhibited better anti-malarial activity compared to P. debilis (IC50 12.2 μg/ml with CQR strain). Furthermore, the methanolic crude of P. urinaria obtained by the cold extraction has good anti-malarial activity towards CQS (IC50 4.1 μg/ml). The concentration of macronutrients (calcium and magnesium) and trace metals (copper, manganese, iron and zinc) from three Phyllanthus species i.e. P. debilis Klein ex Wild., Phyllanthus niruri L., P. urinaria L. and Alpinia conchigera Griff. were determined using microwave digestion method and analyzed by Flame Atomic Absorption Spectroscopy. Standard Reference Material 1547 (peach leaves) was used to validate the method throughout this study. The recovery values were in the range of 80% to 120% which were in very good agreement with the certified values. The three Phyllanthus species and leaves of A. conchigera showed the highest concentration of calcium compared to other metals and macronutrients studied. The significant presence of all the important macronutrients and trace metals which are essential for human health and wellbeing substantiate their use medicinally in traditional practices.