Fast and environmentally friendly quantitative analysis of active agents in anti-diabetic tablets by an alternative laser-induced breakdown spectroscopy (LIBS) method and comparison to a validated reversed-phase high-performance liquid chromatography (RP-HPLC) method

Rapid, Validated UPLC-MS/MS Method for Determination of Glibenclamide in Rat Plasma

Quick and specific bioanalytical methods are required for analyzing drugs in biological samples. A simple, quick, sensitive, and specific UPLC-MS/MS method was developed and validated for glibenclamide determination in plasma samples. The plasma samples were processed by protein precipitation technique. Glimepiride was used as internal standard (IS). Glibenclamide and glimepiride were eluted on C18 column (Acquity UPLC®BEH). Mobile phase consisting of acetonitrile (0.1% formic acid) and water (0.1% formic acid) was pumped in binary gradient mode at flow rate of 150 μL/min. Glibenclamide and IS elution time was about 1.0 min, and total run time was 2.0 min. The mass spectrometer (triple-quadrupole) was operated in positive electrospray ionization mode. Sodium adducts [M + Na]+ of glibenclamide and IS were monitored in MRM mode. A linear calibration curve was obtained in the range of 10-1280 ng/mL, with regression equation Y = 0.0076 X – 0.0165 and linear regression coefficient r2 = 0.999. Lower limit of quantitation was 10 ng/mL. Accuracy of the method at LQC, MQC, and HQC was 109.7% (± 6.7), 93.6% (± 0.4), and 99.3% (± 1.9), respectively. The coefficient of variation for precision at all QC concentrations was less than 6%. Recovery at LLQC, MQC, and HQC was 104.2% (± 4.9), 100.6% (± 0.9), and 102.9% (± 5.8), respectively. The method was successfully implemented for pharmacokinetic investigations (in-house data).

Accuracy enhancement of laser induced breakdown spectroscopy by safely low-power discharge

Improvement in detection accuracy is an important and hot topic for laser induced breakdown spectroscopy (LIBS). Discharged-pulse assisted (DPA) plasma has been investigated as an effective way to enhance analytical capabilities and accuracy of LIBS. Most of reported DPA experiments have been performed using high voltage and power to comprehend spectrum enhancement. For safety concerns and maneuverability of LIBS equipment; low power and small current discharge are viable for industrial application. In this paper, the enhanced spectra with many extra peaks and higher line intensities were also detected, realized by a low-power discharge assisted LIBS (Max. 2.8 kV and ~1 mA), which are much lower than reported in literature ~MW discharge. The number of atomic peaks of the sample increases, on the other hand, and gradual peaks become stronger with the increase of discharged HV from 1 kV to 1.5 kV, 1.75 kV, 2 kV, 2.5 kV and 2.8 kV. The discharge current increases from 0.2 mA to 1.5 mA, which is almost threshold discharge voltage. After processing, the original spectra, including the peak shift and peak correction by statistics and physics, resulted in achievement of better line stability in terms of relative standard deviation (RSD) of ash, carbon, and volatile coal samples with root mean square error prediction (RMSEP) of 0.4864, 0.3682, 0.3374 and the linear regression coefficient R² = 0.99, 0.99,0.98, respectively. The result proposes a promising method to improve detection accuracy of LIBS with simple setup, high safety and low-cost.

Mid-infrared, long wave infrared (4-12 μm) molecular emission signatures from pharmaceuticals using laser-induced breakdown spectroscopy (LIBS)

In an effort to augment the atomic emission spectra of conventional laser-induced breakdown spectroscopy (LIBS) and to provide an increase in selectivity, mid-wave to long-wave infrared (IR), LIBS studies were performed on several organic pharmaceuticals. Laser-induced breakdown spectroscopy signature molecular emissions of target organic compounds are observed for the first time in the IR fingerprint spectral region between 4-12 μm. The IR emission spectra of select organic pharmaceuticals closely correlate with their respective standard Fourier transform infrared spectra. Intact and/or fragment sample molecular species evidently survive the LIBS event. The combination of atomic emission signatures derived from conventional ultraviolet-visible-near-infrared LIBS with fingerprints of intact molecular entities determined from IR LIBS promises to be a powerful tool for chemical detection.