Sensitivity enhancement of aminoglycosides in hydrophilic interaction liquid chromatography with tandem mass spectrometry by post-column addition of trace sodium acetate in methanol

Abstract

The development of a sensitive and accurate analytical method for monitoring aminoglycosides in food, environmental, and clinical samples is needed for many purposes. This study found that the responses of sodiated and protonated aminoglycosides in hydrophilic interaction chromatography with tandem mass spectrometry were enhanced upon addition of sodium acetate in methanol (5 mg L at a flow rate of 0.2 mL min) as a post-column reagent. The sensitivities of sodiated spectinomycin, kanamycin, gentamicins, neomycin, and amikacin were significantly higher than those of the protonated molecules. Streptomycin and dihydrostreptomycin only formed protonated molecules, suggesting the preferential ionisation of the guanidine moieties in these aminoglycosides. The limits of quantification of these aminoglycosides were 0.19-2.5 ng mL. Notably, this is the first quantification of aminoglycosides that uses the sodiated molecules. The enhancement technique enables us to eliminate a concentration step from the clean-up process from food samples. We also proposed a rapid analytical method for residual aminoglycosides in milk and meat samples; validation showed good accuracy and precision of this method at the Japanese maximum residual limits of aminoglycosides (40-500 µg kg). The application of this method to contaminated bovine tissues revealed remarkably high residual levels of kanamycin. This technique will be useful for the sensitive detection of aminoglycosides not only in food, but also in environmental samples and human plasma.

An optimized method for the detection and spatial distribution of aminoglycoside and vancomycin antibiotics in tissue sections by mass spectrometry imaging

“…Due to their structures, only the sodium adducts of kanamycin, amikacin, and vancomycin were detected following MSI analysis of the on‐tissue spotting experiments. This ion formation is commonly reported during the MALDI MS analysis of carbohydrate/glycan type compounds such as these 72,73 . Different tissue washing times were investigated, ranging from 15 to 90 s. The results presented in Figure 1 for kanamycin, amikacin, streptomycin, and vancomycin were taken from the 3 × 30 s wash and demonstrate a significant increase in detection sensitivity in the washed samples compared to the unwashed samples.…”

“…This ion formation is commonly reported during the MALDI MS analysis of carbohydrate/glycan type compounds such as these. 72,73 Different tissue washing times were investigated, ranging from 15 to 90 s. The results presented in Figure 1 for kanamycin, amikacin, streptomycin, and vancomycin were taken from the 3 × 30 s wash and demonstrate a significant increase in detection sensitivity in the washed samples compared to the unwashed samples. The signal for each antibiotic remained within the area where it was spotted, demonstrating minimal-to-no delocalization with this method, this is demonstrated more clearly in supplementary Figure S2a.…”

Development of an Analytical Method for Kasugamycin Residue in Herbal Medicine, <i>Achyranthes japonica</i> Nakai

“…The HILIC column acts effectively on polar basic compounds and aminoglycosides, but its retention time was short, and peak tailing was confirmed, which required improvement, as seen in Fig. 1(b) [20][21]. An amide column is a form in which polar amide groups are bound [7].…”

Optimizing oxytocin LC-MS/MS sensitivity by choosing the right column

“…There are several options to enhance the sensitivity of LC-MS/MS in bioanalytical applications. Besides the improvement of the mass spectrometer in itself, common strategies include sensitivity enhancement through additives to the mobile phase or derivatization [ [6] , [7] , [8] , [9] , [10] ], by manipulating injection or focusing [ 11 , 12 ], or by optimizing sample pre-treatment [ [13] , [14] , [15] ].…”