standard ennb1  (LGC Standards)

Journal: ACS Omega

Article Title: Matrix-Aware LC–MS/MS Quantification of Cyhexatin in Chemically Complex Herbal Matrices Using DOE-Assisted Extraction Optimization

doi: 10.1021/acsomega.6c05657

Figure Lengend Snippet: Overview of the analytical workflow developed for LC–MS/MS determination of cyhexatin in herbal matrices. DOE-guided multivariate optimization (FFD followed by BBD) was applied to improve extraction recovery and quantitative performance. Matrix-matched calibration and surrogate IS normalization were subsequently used to reduce matrix-dependent bias and within-matrix signal variability during quantitative analysis.

Article Snippet: Cyhexatin reference standard (purity ≥99.7%) and triphenyl phosphate (TPP, purity ≥99.9%; Figure S1 ) were obtained from LGC Standards (Teddington, UK).

Techniques: Liquid Chromatography with Mass Spectroscopy, Extraction

Journal: ACS Omega

Article Title: Matrix-Aware LC–MS/MS Quantification of Cyhexatin in Chemically Complex Herbal Matrices Using DOE-Assisted Extraction Optimization

doi: 10.1021/acsomega.6c05657

Figure Lengend Snippet: Comparison of cyhexatin (100 ppb) recovery obtained under a representative empirical extraction condition for Angelicae Gigantis Radix and Paeoniae Radix. Bars represent mean recovery values and error bars indicate standard deviations ( n = 3). Individual points correspond to replicate measurements. The shaded region indicates the Codex acceptance range for pesticide residue recovery (70–120%). A statistically significant difference between the two matrices was observed (two-tailed Welch’s t -test, p = 0.00064). The pronounced divergence in recovery under identical extraction conditions illustrates the limitation of empirical optimization for chemically complex herbal matrices and supports the use of multivariate DOE optimization in the subsequent method development.

Article Snippet: Cyhexatin reference standard (purity ≥99.7%) and triphenyl phosphate (TPP, purity ≥99.9%; Figure S1 ) were obtained from LGC Standards (Teddington, UK).

Techniques: Comparison, Extraction, Residue, Two Tailed Test

Journal: ACS Omega

Article Title: Matrix-Aware LC–MS/MS Quantification of Cyhexatin in Chemically Complex Herbal Matrices Using DOE-Assisted Extraction Optimization

doi: 10.1021/acsomega.6c05657

Figure Lengend Snippet: Workflow of the modified QuEChERS-based sample preparation procedure used for the determination of cyhexatin in herbal medicines. The scheme illustrates sequential sample hydration, extraction using formic acid-modified hexane/MTBE, dispersive solid phase extraction cleanup, solvent evaporation, reconstitution in methanol, and final clarification prior to LC–MS/MS analysis.

Article Snippet: Cyhexatin reference standard (purity ≥99.7%) and triphenyl phosphate (TPP, purity ≥99.9%; Figure S1 ) were obtained from LGC Standards (Teddington, UK).

Techniques: Modification, Sample Prep, Extraction, Solvent, Evaporation, Clarification Assay, Liquid Chromatography with Mass Spectroscopy

Journal: ACS Omega

Article Title: Matrix-Aware LC–MS/MS Quantification of Cyhexatin in Chemically Complex Herbal Matrices Using DOE-Assisted Extraction Optimization

doi: 10.1021/acsomega.6c05657

Figure Lengend Snippet: Representative MRM chromatograms obtained under optimized LC–MS/MS conditions demonstrating method selectivity. Panels (A–C) correspond to (A) standard solution at the LLOQ level, (B) blank matrix extract, and (C) pre-extraction spiked sample at the LLOQ level. Screening (m/z 369.2 → 205.1) and confirmatory (m/z 369.2 → 287.3) transitions are shown for both Angelicae Gigantis Radix and Paeoniae Radix. The orange box indicates the expected retention time window of cyhexatin. A minor background signal was observed in the screening transition of the Angelicae Gigantis Radix blank extract within this window; however, no corresponding signal was detected in the confirmatory transition. The absence of a consistent screening-to-confirmatory transition ratio in the blank sample indicates that the observed signal originates from matrix-derived interference rather than residual analyte. In contrast, the characteristic screening-to-confirmatory transition ratio was consistently observed in both the standard and pre-extraction spiked samples. All chromatograms are displayed using identical intensity and time scales to allow direct comparison.

Article Snippet: Cyhexatin reference standard (purity ≥99.7%) and triphenyl phosphate (TPP, purity ≥99.9%; Figure S1 ) were obtained from LGC Standards (Teddington, UK).

Techniques: Liquid Chromatography with Mass Spectroscopy, Extraction, Derivative Assay, Comparison