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[Display omitted] • Hollow RuCu nanospheres as SERS substrates are first synthesized. • Lowest detection concentration of Sudan I is down to 0.1 mg/L. • Three illegal food additives at ultralow concentrations are examined. In this work, hollow ruthenium-cooper (RuCu) bimetallic nanospheres were synthesized via a facile galvanic replacement reaction with cobalt nanoparticles as a sacrificial template. The well-defined hollow nanospheres exhibit excellent SERS activity towards the detection of Sudan I at the lowest concentration of 0.1 mg/L with a relative standard deviation around 10%. Following, satisfactory determination of prohibited colorants acid orange II, rhodamine B, and malachite green was achieved with the RuCu SERS substrate. This study demonstrates a novel and cost-effective SERS substrate for efficient detection of illegal food additives. [ABSTRACT FROM AUTHOR]

[Display omitted] • A Cu 2 O-Ag/AF-C 3 N 4 surface-enhanced Raman spectroscopy substrate was prepared. • The substrate exhibited high sensitivity and reproducibility. • The substrate can rapidly and simultaneously detect different illegal drugs. Illegal additives can bring the economic benefit, resulting in the continuous irregularities in the use of illegal additives. In this study, a method for rapid, sensitive, and simultaneous detection of multiple illegal additives including enrofloxacin, malachite green, nitrofurazone, and Sudan Ⅰ in feed and food samples by surface-enhanced Raman spectroscopy (SERS) with Cu 2 O-Ag/AF-C 3 N 4 composite substrate was developed. A Cu 2 O-Ag/AF-C 3 N 4 composite substrate was prepared by reacting Cu 2 O modified by AF-C 3 N 4 nanosheets with AgNO 3 solution. The substrate has a limit of detection (LOD) of 1.29 × 10-6 mg/L, a good linear relationship of between 10-6 and 10-2 mg/L, and an R2 value of 0.95 for Rhodamine B detection. Furthermore, the substrate showed high uniformity and reproducibility, with relative standard deviations (RSD) of 6.74% and 4.85%, respectively. Adding AF-C 3 N 4 nanosheets not only increased the enhancement effect of the substrate, which was 4.4 times of that before addition, but also endowed it with good self-cleaning characteristics owing to its excellent photocatalytic activity. The substrate can be reused, with over 80% of the original Raman signal strength remaining after four repeat uses. The SERS based on the above substrate was used to detect the illegal additives, the LOD of enrofloxacin, malachite green, nitrofurazone, and Sudan Ⅰ can reach 4.67 × 10-4 mg/L, 2.57 × 10-5 mg/L, 5.7 × 10-7 mg/L and 6.92 × 10-5 mg/L. The results reveal that this substrate has great application potential in feed and food safety. [ABSTRACT FROM AUTHOR]

In this work, the aggregation behavior of calix[4]resorcinol derivative containing N -methyl- d -glucamine moieties on the upper rim and sulfonate groups on the lower rim in mixture with cationic surfactant, N -hexadecyl- N '-methyl viologen, was investigated by set of physical-chemical methods. It was found that the vesicular aggregates were formed in the mixed macrocycle–surfactant system based on host-guest interaction. The capability of these vesicles to encapsulation of both hydrophobic (Sudan I) and hydrophilic (Rhodamine B) compounds was investigated. [ABSTRACT FROM AUTHOR]