Multi-pesticide residue screening, identification, and quantification analysis in various fruits and vegetables by UHPLC-Q Exactive HRMS.

A general strategy for qualitative screening and quantitative analysis of 403 pesticides in various fruits and vegetables was developed using ultrahigh-performance liquid chromatography (UHPLC) in conjunction with a Thermo Q Exactive Focus high-resolution mass spectrometer, relying on an executable compound database comprised of the exacted mass of precursor ions, retention times, and fragment ions. Taking advantage of the powerful separation capacity of UHPLC, an Orbitrap analyzer with high sensitivity in full scan mode and elevated mass resolution of product ions in the MS/MS mode, eight pairs of isomers and fifty-seven groups of isobaric compounds were selectively identified. The method was then systematically assessed and validated for eight fruits and vegetables, in terms of screening detection limit (SDL), matrix effects, recovery, and precision over 400 pesticides.

Determination of multiclass contaminants in chilli powder based on magnetic multiwalled carbon nanotubes and UPLC-QTOF/MS.

A multiclass analysis approach was developed using magnetic multiwalled carbon nanotubes sorbents and ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) for the rapid screening and simultaneous determination of 216 contaminants including 15 mycotoxins, 9 synthetic colourants, and 192 pesticides in chilli powder. The sample preparation process was optimized. The optimal preparation procedure utilized NaCl and NaAc as the salting-out agents, and FeO-MWCNTs as the sorbents, resulting in reduced chemical consumption, improved cleaning performance, and facilitated high-throughput analysis.

UPLC-Q-TOF/MS-based metabolomic analysis reveals the effects of asomate on the citrus fruit.

The regulation of the sugar-acid ratio is of great significance to the improvement of citrus fruit quality. The citric acid level in fruit is influenced by many factors. Among them, cultivar selection and production practices are the most important strategies under the grower's control.

Parameter Optimization of a Potted Seedling Tray Prepared from a Mixture of Rice Straw and Fermented Cow Manure Using the Response Surface Methodology.

Biomass is generally regarded as a significant renewable resource, which can be used as the raw material for bioproducts. In the study, a mixture of rice straw and fermented cow manure was utilized to produce potted seedling trays, which are biodegradable and environmentally friendly. The effects of process parameters on the quality of final products were assessed by measuring damage resistance (DR) and expansion ratio (ER).

Simultaneous determination of multiclass plant growth regulators in fruits using the quick, easy, cheap, effective, rugged, and safe method and ultra-high performance liquid chromatography-tandem mass spectrometry.

In this study, a modified quick, easy, cheap, effective, rugged, and safe method combined with ultra-high performance liquid chromatography and tandem mass spectrometry was developed for the multiclass determination of 28 plant growth regulators in various fruits. Different extraction solvents and adsorbents, including primary secondary amine, octadecylsilyl, graphitized carbon black, and zirconia-based sorbent, were investigated. Internal calibration and isotope internal standards, chlormequat chloride-d , mepiquat chloride-d , indole-3-acetic acid-d , and forchlorfenuron-d were used to improve accuracy.

Application of a multiclass screening method for veterinary drugs and pesticides using HPLC-QTOF-MS in egg samples.

A multi-class screening method for the determination of veterinary drugs and pesticides in eggs was developed by high performance liquid chromatography quadrupole-time-of-flight mass spectrometry (HPLC-QTOF-MS). A single-injection workflow was developed for qualitative analysis, and method validation was conducted in terms of retention time deviation (ΔRt), exact mass error (Δm), selectivity, specificity, precision and trueness. The characteristic fragment ions in information dependent acquisition (IDA) mode were summarized for retrospective and non-target screening.

Development of a modified QuEChERS method based on magnetic multiwalled carbon nanotubes for the simultaneous determination of veterinary drugs, pesticides and mycotoxins in eggs by UPLC-MS/MS.

A modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method was developed for the simultaneous determination of veterinary drugs, pesticides and mycotoxins in eggs by ultrahigh-pressure liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Several extraction conditions were tested and optimized, and the obtained extraction efficiency of all the targeted compounds (particularly macrolides) could fulfill the requirements. In the purification procedure, magnetic multiwalled carbon nanotubes (FeO-MWCNTs) were used as adsorbents, and an external magnet was utilized to achieve a faster adsorbent separation, compared to the traditional centrifugation process.

A multi-residue method for the determination of pesticides in tea using multi-walled carbon nanotubes as a dispersive solid phase extraction absorbent.

A modified QuEChERS (quick, easy, cheap, effective, rugged and safe) method using multi-walled carbon nanotubes (MWCNTs) as a dispersive solid phase extraction (d-SPE) absorbent was established for analysis of 78 pesticide residues in tea. A 6 mg MWCNT sample was selected as the optimised amount based on the distribution of pesticide recoveries and clean-up efficiency from 6 mL acetonitrile extracts. The matrix effects of the method were evaluated and matrix-matched calibration was recommended.

Development and validation of an rp-hplc method for simultaneous determination of Ramipril and Amlodipine in tablets.

An rp-hplc method for the simultaneous determination of Ramipril (RP) and Amlodipine (AL) in tablets was developed and validated by Chinese Pharmacopoeia 2010. The linearity of the proposed method was investigated in the range of 0.01-0.