Determination of twelve neonicotinoid pesticides in chili using an improved QuEChERS method with UPLC-Q-TOF/MS.

In this study, a QuEChERS method based on citrate was developed and utilized for the analysis of twelve neonicotinoid pesticides in fresh red chilies, fresh green chilies, and dried chilies, coupled with ultra-high performance liquid chromatography quadrupole time of flight mass spectrometry (UPLC-Q-TOF/MS). In the sample preparation, acetonitrile containing 1% formic acid was used as the extraction solvent. Anhydrous sodium sulfate replaced the traditional anhydrous magnesium sulfate for water removal, effectively eliminating the issues of salt caking. Graphitized carbon black, octadecyl silica, and primary secondary amine were used as cleaning agents. The method showed good sensitivity, with the limits of quantification below 0.03 mg/kg for fresh chilies and below 0.15 mg/kg for dried chilies. Values of matrix effects ranged from -19.5% to 8.4%, and the recovery was 86.9% - 105.2%. The analytical method provided an effective tool for the high throughput detection of neonicotinoid pesticide residues in multiple chili matrices.

Determination of multiple mycotoxins in chili powder using cold-induced liquid-liquid extraction and Fe3O4@MWCNTs-NH2 coupled with UPLC-Q-TOF/MS.

Food matrix interference is still a big challenge in analyzing multiclass mycotoxins. Herein, a novel cold-induced liquid-liquid extraction-magnetic solid phase extraction (CI-LLE-MSPE) coupled with ultra-high performance liquid chromatography-quadrupole time of flight mass spectrometry (UPLC-Q-TOF/MS) method was explored for the simultaneous determination of multiple mycotoxins in chili powders. Fe3O4@MWCNTs-NH2 nanomaterials were prepared and characterized, and the factors affecting the MSPE process were investigated. Based on this, the CI-LLE-MSPE-UPLC-Q-TOF/MS method was established for determining ten mycotoxins in chili powders. The proffered technique eliminated the matrix interference effectively and demonstrated strong linearity (0.5-500 µg/kg, R2 ≥ 0.999), high sensitivity (limit of quantification was 0.5-1.5 µg/kg), and the recovery was 70.6%-111.7%. The extraction process is simpler than conventional methods, as the adsorbent can be separated using magnets, and reusable adsorbents are beneficial in reducing costs. In addition, the method can provide a valuable reference for pretreatment procedures for other complex matrices.

Profile of Human Milk Phospholipids at Different Lactation Stages with UPLC/Q-TOF-MS: Characterization, Distribution, and Differences.

Human milk phospholipids are important for the regular growth and development of infants. Ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF-MS) was employed to qualitatively and quantitatively analyze 277 phospholipid molecular species in 112 human milk samples to obtain a detailed profile of human milk phospholipids along the lactation stage. MS/MS fragmentation patterns of sphingomyelin, phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, and phosphatidylserine were characterized in detail. Phosphatidylcholine is the most dominant group, followed by sphingomyelin. PC(18:0/18:2), SM(d18:1/24:1), PE(18:0/18:0), PS(18:0/20:4), and PI(18:0/18:2) showed the highest average concentration among all of the phosphatidylcholine, sphingomyelin, phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol molecular species, respectively. The fatty acids attached to the phospholipid molecules were mainly palmitic, stearic, oleic, and linoleic acids, and the plasmalogens decreased along the lactation stage. The increase of sphingomyelins and phosphatidylethanolamines and the decrease of phosphatidylcholines are the key changes from colostrum to transitional milk; the increase of lysophosphatidylcholines and lysophosphatidylethanolamines and the continuous decrease of phosphatidylcholines are the vital changes from transitional milk to mature milk.

Hydrogel composite of lanthanum and Halorubrum ejinoor sp. cell lysate as an adsorbing material.

OBJECTIVES: Although halophilic archaea are rich in natural environments, their biotechnological applications are not as prevalent as those of other extremophiles, such as thermophiles and alkaliphiles. This study presents an simple method to prepare a hydrogel composite using crude cell lysate of a halophilic archaea, Halorubrum ejinoor sp. (H.e.) which was isolated from a saline lake in Inner Mongolia, China. Furthermore, formation mechanism and potential applications of the hydrogel as an adsorbing material are discussed. RESULTS: Halorubrum ejinoor sp. (H.e.) cell lysate was firstly prepared by adding pure water onto the H.e. cell pellet, followed by a short incubation at 60 °C. The cell lysate was injected into different metal ion (or H+) solutions to obtain the hydrogel composite. It was observed that H+, Fe3+, La3+, Cu2+, and Ca2+ induced gelation of the cell lysate, while Fe2+, Co2+, Ni2+, Mg2+, Na+, and K+ did not. DNA and extracellular polysaccharides (EPS) in the H.e. cell lysate were found to be responsible for the gelation reaction. These results suggest that DNA and EPS should be crosslinked by metal ions (or H+) and form a networked structure in which the metal ion (or H+) serves as an anchor point. Potential application of the hydrogel as an adsorbing material was explored using La3+-induced H.e. hydrogel composite. The hydrogel composite can adsorb the fluoride, phosphate and DNA-binding carcinogenic agents, such as acridine orange. CONCLUSIONS: The simplicity and cost effectiveness of the preparation method might make H.e. hydrogel a promising adsorbing material. This work is expected to expand the technical applications of haloarchaea.