On-site monitoring of nandrolone in cattle farming samples by portable atmospheric pressure chemical ionization mass spectrometry with ambient sampling

Nandrolone (NT) is a type of androgen anabolic steroid that is often illegally used in cattle farming, leading to unpredictable harm to human health via the food chain. In this study, a rapid detection method for NT in the samples of cattle farming was established using a portable mass spectrometer. The instrument parameters were optimized, including a thermal desorption temperature of 220 °C, a pump speed of 30 %, an APCI ionization voltage of 3900 v, and an injection volume of 6 μL. The samples of bovine urine, feed, sewage, and tissue were selected, and extracted using a solution of methanol:acetonitrile (1:1, v/v), followed by spiking a NT standard solution (1000 ng·mL-1) and ionization through the APCI ion source for detection. The results showed that NT could not be detected in beef and feed due to the complexity of the matrix, while clear signals of NT ions were observed in bovine urine and sewage samples, with LODs of 1000 and 100 ng·mL-1, respectively. Furthermore, quantitative analysis was attempted, and a good linear relationship (R2 = 0.9952) was observed for NT in sewage within the range of 100 to 1000 ng·mL-1. At spiked levels of 100, 500, 1000 and 2000 ng mL-1, the recovery rates ranged from 74.3 % to 92.8 %, with a relative standard deviation (n = 6) of less than 15 %. In conclusion, this detection method offers the advantages of simplicity, rapidity, strong timeliness, and specificity, making it suitable for on-site detection. It can be used for qualitative screening of nandrolone in bovine urine and quantitative analysis of nandrolone in sewage.

High-throughput method based on a novel thin-film microextraction coating for determining macrolides and lincosamides in honey

A high-throughput method using a new ZIF-8@GO thin-film microextraction coating was established for determining macrolides and lincosamides in honey. The coating preparation parameters (ZIF-8@GO synthesis conditions, coating material proportions, dipping time) and analysis parameters (sample diluent solvent, adsorption and desorption conditions using the ZIF-8@GO coating) were optimized. The optimized parameters were: diluent solvent sodium carbonate/sodium bicarbonate buffer solution (pH 9), adsorption time 45 min, desorption time 5 min, desorption solvent 45:40:15 v/v/v methanol/acetonitrile/water. The extracted targets were determined by ultra-high performance liquid chromatography tandem mass spectrometry. The recoveries of 10 analytes were 67.5-107.2% and the detection and quantification limits were 0.1-0.4 and 0.4-1.4 μg/kg, respectively. The method could analyze 96 samples per run. The minimal manual time and effort is required since the bulk of the sample processing is fully automated. It was a useful and efficient method for monitoring drug residues and was successfully used to analyze real samples.

In-situ fabrication of zeolite imidazole framework@hydroxyapatite composite for dispersive solid-phase extraction of benzodiazepines and their determination with high-performance liquid chromatography-VWD detection

A novel zeolite imidazole framework@hydroxyapatite composite (ZIF-8@HAP) was constructed via in-situ growth and developed for efficient dispersive solid-phase extraction (DSPE) of three benzodiazepines from urine samples. The prepared composite was characterized by scanning electron microscopy, energy-dispersive spectrometer, Fourier-transform infrared spectrometry, X-ray diffractometry, zeta potential analyzer, and nitrogen adsorption-desorption experiment. Characterization results showed typical dodecahedron ZIF-8 crystals that were uniformly located on the surface of rod-like HAP. The combination of ZIF-8 and HAP made the surface area significantly enhanced from 4.68 to 205.44 m² g^-1. Compared with a commercial C₁₈ adsorbent, ZIF-8@HAP exhibited superior removal performance for interfering components from urine and offered better extraction properties for the analytes. The prepared ZIF-8@HAP was applied as an adsorbent in DSPE, and the main experimental parameters, including pH and ionic strength of solution, adsorbent amount, adsorption time, elution solvent, and volume, were investigated. Under optimal conditions, the adsorption for 250 ng mL^-1 of each analyte in 4 mL of urine was accomplished within 2 min using 60 mg of adsorbent. The method of ZIF-8@HAP-based DSPE followed by high-performance liquid chromatography gave enhancement factors of 13.3-15.3, linear ranges of 2.5-500 ng mL^-1, and limits of detection (S/N = 3) of 0.7-1.4 ng mL^-1. The relative recoveries at three spiked levels ranged from 88.7 - 102% with intra-day and inter-day precisions from 3.0 - 10.3% and 2.3 - 12.3%, respectively. These results indicated that the proposed strategy had promising applicability for convenient, rapid, and efficient determination of benzodiazepines in urine samples.Graphical abstract In-situ fabrication of ZIF-8@HAP composite for dispersive solid-phase extraction of benzodiazepines in urine samples.

Sponges and Sponge-Like Materials in Sample Preparation: A Journey from Past to Present and into the Future

Even though instrumental advancements are constantly being made in analytical chemistry, sample preparation is still considered the bottleneck of analytical methods. To this end, researchers are developing new sorbent materials to improve and replace existing ones, with the ultimate goal to improve current methods and make them more efficient and effective. A few years ago, an alternative trend was started toward sample preparation: the use of sponge or sponge-like materials. These materials possess favorable characteristics, such as negligible weight, open-hole structure, high surface area, and variable surface chemistry. Although their use seemed promising, this trend soon reversed, due to either the increasing use of nanomaterials in sample preparation or the limited scope of the first materials. Currently, with the development of new materials, such as melamine sponges, along with the advancement in nanotechnology, this topic was revived, and various functionalizations were carried out on such materials. The new materials are used as sorbents in sample preparation in analytical chemistry. This review explores the development of such materials, from the past to the present and into the future, as well as their use in analytical chemistry.