madman
Super Moderator
Determination of phosphodiesterase 5 (PDE5) inhibitors in instant coffee premixes using liquid chromatography-high-resolution mass spectrometry (LC-HRMS)
Ahmad Yusri Mohd Yusopa, Linda Xiaoa , Shanlin Fu
ABSTRACT
As a widely consumed beverage, coffee tends to be a target for intentional adulteration. This study describes the application of modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) coupled to liquid chromatography-high-resolution mass spectrometry (LC-HRMS) for simultaneous screening, identification, and quantification of undeclared phosphodiesterase 5 (PDE5) inhibitors in instant coffee premixes (ICPs). The mass spectrometer was operated in auto MS/MS acquisition for simultaneous MS and MS/MS experiments. Qualitative establishments from the suspected-target screening and targeted identification processes led to an unambiguous analyte assignment from the protonated molecule ([M+H]+) precursor ion which is subsequently used for quantification of 23 targeted PDE5 inhibitors. The analytical method validation covered specificity, linearity, range, accuracy, limit of detection (LOD), limit of quantification (LOQ), precisions, matrix effect (ME), and extraction recovery (RE). The specificity was established using the optimised chromatographic separation as well as the distinguishable [M+H]+ precursor ion. The linearity of each target analyte was demonstrated with a coefficient of determination (r2 ) of > 0.9960 over the expected range of sample concentrations. The accuracy ranged from 88.1%–119.3% with LOD and LOQ of < 70 ng/mL and 80 ng/mL, respectively. Excellent precisions were established within 0.4%–9.1% of the relative standard deviation. An insignificant ME within −5.2% to +8.7% was achieved using three different strategies of chromatography, sample extraction, and sample dilution. The RE was good for all target analytes within 84.7%–123.5% except for N-desethylacetildenafil at low (53.8%) and medium (65.1%) quality control levels. The method was successfully applied to 25 samples of ICPs where 17 of them were found to be adulterated with PDE5 inhibitors and their analogues. Further quantification revealed the total amount of these adulterants ranged from 2.77 to 121.64 mg per sachet.
4. Conclusions
A modified QuEChERS extraction procedure coupled to LC-HRMS analysis was fully optimised and validated to determine PDE5 inhibitors and their analogues found as adulterants in ICPs. The process of screening, identification, and quantification were done simultaneously with detailed procedures and examples discussed in this study. These adulterants were comprehensively screened via the suspected-target and non-targeted approaches, utilising the full spectral information of the simultaneous MS and MS/MS experiments. The optimisation of chromatography, sample extraction, and sample dilution led to the minimisation of ME for all 23 targeted PDE5 inhibitors [19]. The applicability of the developed method was then demonstrated using 25 ICP samples. Typically, consumers tend to take extra precaution when taking health supplements, especially in pharmaceutical dosage form compared to consumable products, such as ICPs. Therefore, this kind of adulterated products will put the public at the absolute risk owing to its easy accessibility, either through conventional or online markets. The strategies proposed in this study would be beneficial to tackle the problems of adulterated ICPs, especially with PDE5 inhibitors and their analogues to safeguard the public health.
Ahmad Yusri Mohd Yusopa, Linda Xiaoa , Shanlin Fu
ABSTRACT
As a widely consumed beverage, coffee tends to be a target for intentional adulteration. This study describes the application of modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) coupled to liquid chromatography-high-resolution mass spectrometry (LC-HRMS) for simultaneous screening, identification, and quantification of undeclared phosphodiesterase 5 (PDE5) inhibitors in instant coffee premixes (ICPs). The mass spectrometer was operated in auto MS/MS acquisition for simultaneous MS and MS/MS experiments. Qualitative establishments from the suspected-target screening and targeted identification processes led to an unambiguous analyte assignment from the protonated molecule ([M+H]+) precursor ion which is subsequently used for quantification of 23 targeted PDE5 inhibitors. The analytical method validation covered specificity, linearity, range, accuracy, limit of detection (LOD), limit of quantification (LOQ), precisions, matrix effect (ME), and extraction recovery (RE). The specificity was established using the optimised chromatographic separation as well as the distinguishable [M+H]+ precursor ion. The linearity of each target analyte was demonstrated with a coefficient of determination (r2 ) of > 0.9960 over the expected range of sample concentrations. The accuracy ranged from 88.1%–119.3% with LOD and LOQ of < 70 ng/mL and 80 ng/mL, respectively. Excellent precisions were established within 0.4%–9.1% of the relative standard deviation. An insignificant ME within −5.2% to +8.7% was achieved using three different strategies of chromatography, sample extraction, and sample dilution. The RE was good for all target analytes within 84.7%–123.5% except for N-desethylacetildenafil at low (53.8%) and medium (65.1%) quality control levels. The method was successfully applied to 25 samples of ICPs where 17 of them were found to be adulterated with PDE5 inhibitors and their analogues. Further quantification revealed the total amount of these adulterants ranged from 2.77 to 121.64 mg per sachet.
4. Conclusions
A modified QuEChERS extraction procedure coupled to LC-HRMS analysis was fully optimised and validated to determine PDE5 inhibitors and their analogues found as adulterants in ICPs. The process of screening, identification, and quantification were done simultaneously with detailed procedures and examples discussed in this study. These adulterants were comprehensively screened via the suspected-target and non-targeted approaches, utilising the full spectral information of the simultaneous MS and MS/MS experiments. The optimisation of chromatography, sample extraction, and sample dilution led to the minimisation of ME for all 23 targeted PDE5 inhibitors [19]. The applicability of the developed method was then demonstrated using 25 ICP samples. Typically, consumers tend to take extra precaution when taking health supplements, especially in pharmaceutical dosage form compared to consumable products, such as ICPs. Therefore, this kind of adulterated products will put the public at the absolute risk owing to its easy accessibility, either through conventional or online markets. The strategies proposed in this study would be beneficial to tackle the problems of adulterated ICPs, especially with PDE5 inhibitors and their analogues to safeguard the public health.
