Rapid Determination of Tetracyclines Hydrochloride Using ATR FT-MIR Spectroscopy

Effectively reducing antibiotic contamination and resistance in fishery by efficient gastrointestine-blood delivering dietary millispheres

The overuse of antibiotics during the medication treatment is inevitable in the extensively-applied intensive and semi-intensive aquaculture mode; the accompanied antibiotic contamination and antimicrobial resistance pose threats to the ecosystems and cause great loss to the aquaculture industry. To solve the problem, this work introduced the antibiotic-laden dietary millispheres (DMSs) with internal porous structure for the high availability, attractiveness and digestibility to fish. Two types of antibiotics with distinct solubilities - tetracycline chloride (TCH) and sulfadiazine (SDZ) were made into the DMSs, individually, which were then directly adopted in the feeding of fish. Carassius auratus was chosen as the target fish in this work. The mesocosm study demonstrate that, compared with the regular way of oral administration (feeding the mixture of antibiotics and commercial feed pellets), the DMSs could use much less (i.e. one order of magnitude lower) antibiotic dose to reach the equivalent antibiotic concentration in gastrointestine and blood. As a robust alternative, either TCH- or SDZ-laden DMSs achieved efficient drug delivery in vivo, which importantly facilitated the source reduction of antibiotics, the alleviation of antibiotic contamination in fishery and the control of antibiotic resistance especially in sediments.

Facile synthesis of highly efficient fluorescent carbon dots for tetracycline detection

Rampant use of tetracycline in animal feed is a threat to food security, the environment, and human health because of the risk of drug residues. Therefore, it is necessary to establish a sensitive, efficient, and reliable method for qualitative and quantitative detection of tetracycline. In this paper, we synthesized fluorescent carbon dots (FCDs) by thermal cracking of crab shell waste, and obtained a fluorescence quantum yield of 30%. Characterization of the FCDs by transmission electron microscopy, Fourier-transform infrared spectroscopy, ultraviolet visible absorption spectroscopy, and photoluminescence spectroscopy showed that they were fluorescent and evenly distributed with an average size of approximately 10 nm. We designed a sensitive probe for detecting tetracycline using the fluorescence intensity change of the FCDs. This method is sensitive, inexpensive, and environmentally friendly. The concentration of tetracycline was examined by comparing the fluorescence intensities of the FCDs before and after tetracycline addition. The limit of detection for tetracycline was 0.005 mg/L (signal-to-noise ratio = 3), which is promising for method development.

Determination of trace amounts with ATR FTIR spectroscopy and chemometrics: 5-(hydroxymethyl)furfural in honey

The feasibility of Attenuated Total Reflectance Fourier Transform Infrared (ATR FTIR) spectroscopy and chemometric modeling for analysis of trace compounds is studied on the example of 5-(hydroxymethyl)furfural (HMF) in honey up to a concentration of 110 ppm, and compared to results in literature. Randomized repeated measurements of the calibration samples were carried out to prevent analytical artifacts. A partial least squares (PLS) model was calculated for quantitative determination. The considered spectral range has significant influence on the PLS model. Furthermore, averaging of spectra can improve the model quality due to the elimination of statistical noise. A low root mean square error of prediction (RMSEP) of 13 ppm was achieved. Hence, the results indicate that trace compound determination with ATR FTIR spectroscopy is possible, although calibration and modeling efforts are higher compared to standard applications of ATR FTIR spectroscopy and chemometrics.