Comparison of piracetam measured with HPLC-DAD, HPLC-ESI-MS, DIP-APCI-MS, and a newly developed and optimized DIP-ESI-MS

Abstract

The direct inlet probe-electrospray ionization (DIP-ESI) presented here was based on the direct inlet probe-atmospheric pressure chemical ionization (DIP-APCI) developed by our group. It was coupled to an ion trap mass spectrometer (MS) for the detection of more polar compounds such as degradation products from pharmaceuticals. First, the position of the ESI tip, the gas and solvent flow rates, as well as the gas temperature were optimized with the help of the statistic program Minitab® 17 and a caffeine standard. The ability to perform quantitative analyses was also tested by using different concentrations of caffeine and camphor. Calibration curves with a quadratic calibration regression of R (2) = 0.9997 and 0.9998 for caffeine and camphor, respectively, were obtained. The limit of detection of 2.5 and 1.7 ng per injection for caffeine and camphor were determined, respectively. Furthermore, a solution of piracetam was used to compare established analytical methods for this drug and its impurities such as HPLC-diode array detector (DAD) and HPLC-ESI-MS with the DIP-APCI and the developed DIP-ESI. With HPLC-DAD and 10 μg piracetam on column, no impurity could be detected. With HPLC-ESI-MS, two impurities (A and B) were identified with only 4.6 μg piracetam on column, while with DIP-ESI, an amount of 1.6 μg piracetam was sufficient. In the case of the DIP-ESI measurements, all detected impurities could be identified by MS/MS studies. Graphical Abstract Scheme of the DIP-ESI principle.

A new green approach for the reduction of consumed solvents and simultaneous quality control analysis of several pharmaceuticals using a fast and economic RP-HPLC method; a case study for a mixture of piracetam, ketoprofen and omeprazole drugs

“…Many HPLC methods have been reported for PIR analysis in pharmaceuticals, either on its own or in addition to impurities or other drugs. [37][38][39][40][41][42][43] Ketoprofen (KET) is 2-(3-benzoylphenyl) propionic acid. KET belongs is a nonsteroidal anti-inammatory drug (NSAID).…”

Direct analysis from dried blood spot card surfaces with direct probe mass spectrometry – Evaluation study

“…The ionization products are subsequently transferred by the drying gas to the mass analyzer. The analysis is performed under atmospheric pressure, without the need for labor‐intensive sample preparation …”

Quantitative Analysis of Bisphenol A in Recycled Paper with a Novel Direct Inlet Probe-Atmospheric Pressure Photoionization–IonTrap-MS

“…To increase the ionization yield, especially in combination with liquid chromatography, dopants can be used [20]. A dopant is a reactive solvent, which is introduced into the ion source in higher amounts and mainly ionized because of the high surplus in comparison with the target analytes.…”

“…A dopant is a reactive solvent, which is introduced into the ion source in higher amounts and mainly ionized because of the high surplus in comparison with the target analytes. After ionization of the dopant the charge or a proton is transferred to the analyte [20]. The main drawback of this method is that by the introduction of dopants into the ion source, the corresponding mass spectrum becomes more complex [16,20].…”

“…After ionization of the dopant the charge or a proton is transferred to the analyte [20]. The main drawback of this method is that by the introduction of dopants into the ion source, the corresponding mass spectrum becomes more complex [16,20]. Luckily, this problem can be avoided with the presented system due to a pre-heating (e.g., 40°C) of the sample to evaporate the solvent, and therefore, the ion source shows a good sensitivity (absolute amount of analytes) without dopants.…”