Simultaneous determination of 14 sulfonamides and tetracyclines in biogas plants by liquid-liquid-extraction and liquid chromatography tandem mass spectrometry

Abstract

A new method for the analysis of sulfonamides and tetracyclines in heterogenic biogas plant input samples and fermentation residues is introduced. Veterinary antibiotics are only partially absorbed in the animal gut; therefore, animal manure can contain high loads of these substances. Animal manure is used for biogas generation, so antibiotics can enter the anaerobic fermentation process this way. However, only little is known about the fate of antibiotics within this process, also due to the lack of suitable analytical methods for this complex sample matrix. Therefore, we developed a method for the analysis of ten sulfonamides (sulfachloropyridazine, sulfadiazine, sulfadimethoxine, sulfaguanidine, sulfamerazine, sulfamethazine, sulfamethoxazol, sulfamethoxypyridazin, sulfapyridine, sulfathiazole) and four tetracyclines (chlortetracycline, doxycycline, oxytetracycline, tetracycline) in biogas plant input and output samples, including a single liquid-liquid-extraction step and analysis via liquid chromatography (LC) and triple quadrupole mass spectrometry. The detection limit of this method ranges from 0.01 to 0.08 mg kg(-1). Matrix calibration using antibiotic-free cattle feces and isotopic-labeled internal standards enables quantification of antibiotics in different matrices such as animal manure, dung, or fermenter outputs with recovery rates between 70 and 130 %. This makes the method suitable for investigating the fate of antibiotics in animal manure and fermentation processes. A screening of 15 German biogas plants revealed the presence of several antibiotics up to 9 mg kg(-1) (201 mg kg(-1) dry matter). During the fermentation process, elimination occurs; however, with the exception of chlortetracycline, the antibiotic content remains in the same order of magnitude.

Elimination patterns of worldwide used sulfonamides and tetracyclines during anaerobic fermentation

“…Highest elimination rates were observed for chlortetracycline. These results are in agreement with the previous screening (Spielmeyer et al, 2014). However, precise elimination rates are difficult to calculate as several factors influence the actual antibiotic content.…”

“…A screening of 15 German biogas plants revealed the presence of tetracyclines and sulfonamides in both fermenter input and output samples (Spielmeyer et al, 2014). Based on those data, two biogas plants were investigated regarding their antibiotic contents over the course of one year.…”

“…Sample preparation and LC-MS/MS analysis were performed as previously published (Spielmeyer et al, 2014). Briefly, 1 g sample was extracted using citric acid buffer (1 M, pH 4.7, containing 0.05 M EDTA) and dichloromethane, ethanol, methanol (1:3:1, v/v/v).…”

From agricultural fields to surface water systems: the overland transport of veterinary antibiotics

“…For example, SMZ was recently identified as a global indicator for the application of sulfonamides in livestock farming (Jekel et al 2015). The antibiotics were extracted with good recoveries using a citrate buffer and a mixture of organic solvents (methanol, acetonitrile, dichloromethane), then analysed using liquid chromatography tandem mass spectrometry (Spielmeyer et al 2014). The detection limit of these antibiotics ranged from 10 to 75 μg kg −1 for solid samples and from 10 to 300 ng l −1 for liquid samples.…”

A review of the current digestate distribution models: storage and transport

“…The main practice is land application due to the characteristics of the effluent of AD, because it is rich in nitrogen, phosphate and potassium, but on the other hand it may content some heavy metals [9], antibiotics [10], organic pollutants [11] or pathogens that can limit digestate utilization [12]. In many parts of Europe, livestock production is concentrated and intensive, and creates a permanent excess of nutrients, making such areas highly vulnerable from the point of view of nutrient pollution of ground and surface waters [13].…”