{'fraction_non_alphanumeric': 0.028169014084507043, 'fraction_numerical': 0.013001083423618635, 'mean_word_length': 5.347079037800687, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Molecularly imprinted solid-phase extraction combined with high-performance liquid chromatography for analysis of trace olaquindox residues in chick feeds.

BACKGROUND
Olaquindox, one of the antimicrobial growth accelerants, is usually used as a feed additive in livestock production to improve feed efficiency. Due to health concerns over possible carcinogenic, mutagenic and photoallergenic effects of olaquindox on animals, the development of a simple, rapid and sensitive analytical method for determination of olaquindox is crucial and necessary.


RESULTS
In this paper, a novel and hydrophilic functionalised material of olaquindox-imprinted polymer was synthesised in aqueous solution by a surface molecular imprinting in combination with a sol-gel process. This imprinted material was characterised by Fourier transform infrared, scanning electron microscopy, and static and kinetic adsorption experiments, and results showed that it had good recognition and selective ability, and fast adsorption-desorption dynamics for olaquindox. Applying the prepared material as sorbent, a method of molecularly imprinted solid-phase extraction (MISPE) for separation and analysis of olaquindox residues in feeds coupled with HPLC was presented. Under the selected MISPE condition, the detection limit (S/N = 3) for olaquindox was 68.0 ng L(-1), the RSD for five replicate extractions of 50 µg L(-1) olaquindox was 9.8%. The blank chick feed samples spiked with olaquindox at 0.0025 and 0.010 mg g(-1) levels were extracted and determined by the developed method, with recoveries ranging from 90% to 96%.


CONCLUSION
This method was applied for enrichment and analysis of olaquindox in animal feed samples with good accuracy and repeatability. This study will provide a sensitive and fast method for the monitoring of olaquindox residues in foods.