Simultaneous analysis of multi-class antibiotics in bottled water using large-volume direct-injection LC-MS/MS

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Food Safety

Background:

• Antibiotic contamination in water sources is a growing concern.
• Existing analytical methods may lack sensitivity or efficiency for comprehensive antibiotic profiling.
• Bottled water, a common drinking source, requires thorough assessment for potential contaminants.

Purpose of the Study:

• To develop and validate a novel large-volume direct-injection (LVDI) method for simultaneous analysis of 69 antibiotics.
• To compare the LVDI method's performance against a conventional solid-phase extraction (SPE) method.
• To investigate the occurrence and levels of various antibiotic classes in commercially available bottled water.

Main Methods:

• Development and validation of a large-volume direct-injection (LVDI) method coupled with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS).
• Optimization of ion source parameters and injection volume (100 μL) for enhanced sensitivity and peak shape.
• Comparative analysis with a solid-phase extraction (SPE) method for antibiotic recovery and detection limits.

Main Results:

• The LVDI method achieved good absolute recoveries (80-120%) for most of the 69 target antibiotics.
• LVDI demonstrated superior or comparable performance to SPE, with limits of detection generally below 1 ng L^-1.
• Analysis of 25 bottled water brands revealed 54 antibiotics present, with over 10 detected in 9 brands; quinolones and sulfonamides predominated.

Conclusions:

• The validated LVDI-UHPLC-MS/MS method is effective for sensitive and simultaneous quantification of a wide range of antibiotics in bottled water.
• Bottled water represents a potential route for human exposure to multiple antibiotics, necessitating ongoing monitoring.
• The study highlights the prevalence of quinolone and sulfonamide antibiotics in bottled water, with variations observed between water types.