Study of Analytical Methods for Determining 16 Organophosphorus Pesticide Residues in Panax Notoginseng and Aucklandia Lappa Decne by Automated Solid-Phase Extraction System and GC/MS

A fast and sensitive multi-residue analytical method was developed for the determination of organophosphorus pesticide residues in Panax notoginseng and Aucklandia lappa decne by comparing an ultrasonic extraction and homogenate extraction approach coupled with automated solid-phase extraction system and gas chromatography-mass spectrometry (GC/MS). Various factors affecting the homogenate extraction and purification efficiency were investigated in detail. The optimum conditions for homogenate extraction of organophosphorus pesticide residues from Panax notoginseng and Aucklandia lappa decne were 60 mL dichloromethane, 10000 r/min of extracting revolution speed and 2 min of extracting time. The extracts were cleaned up by automated solid-phase extraction system and determined by GC/MS. Under the optimum conditions, the results of the homogenate extraction approach were compared with those of the ultrasonic extraction, and the homogenate extraction approach was used to extract the samples. The average recoveries of the method by a homogenate extraction approach coupled with automated solid-phase extraction system and GC/MS ranged from 72.56% to 96.70%, and RSDs were 0.05~0.14%, which allowed the determination of 16 organophosphorus pesticide residues in Panax notoginseng and Aucklandia lappa decne. The results indicated that the proposed method can apply for the determination of organophosphate pesticides residues in Panax notoginseng and Aucklandia lappa decne with high accuracy and precision.

Quantitative Screening Method for Erythromycin and Tylosin in Honey Using RapidFire Mass Spectrometry

Background: Antibiotic resistance and other adverse health issues related to the presence of drug residues in honey are of great concern to the United States, United Kingdom, and many other countries. The majority of quantitative testing methods using mass spectrometry are not capable of performing high-throughput analysis. Furthermore, the methods that are available are labor intensive and time consuming. Objective: There is a need for a rapid quantitative screening method to detect veterinary drug residues in honey for laboratories performing regulatory analysis. Herein is a method that utilizes automated solid-phase extraction that is directly coupled to a mass spectrometer for the screening of two macrolide drug residues, tylosin and erythromycin, in honey. Method: This method utilizes automated solid-phase extraction that is directly coupled to a triple quadrupole mass spectrometer for quantitative analysis. The optimized procedure requires minimal sample preparation, and can extract and analyze a sample on the mass spectrometer in approximately 20 s. Results: A complete method validation procedure was conducted to evaluate the effectiveness and robustness of this quantitative screening method. Quantitative results were within 15% of the target value, and no false positives or negatives were observed. Conclusions: The method validation illustrates that this is a viable screening method for regulatory analysis. Highlights: Complete automated extraction and analysis was performed, which involved minimal labor. Extraction and analytical times were reduced by >98% when compared with conventional methods. Furthermore, accurate quantitative results were generated on both fortified spikes and incurred honey residues.