•A novel chiral ferrocene based stationary phase NFcBEs were prepared.•The developed stationary phase indicated both RPLC and NPLC retention mechanisms.•It could be used for separation of amino acid and drug carvedilol racemates.•The retention behaviors of carvedilols were investigated using the density functional theory.A brush-type chiral stationary phase, N-ferrocenyl benzoyl-(1S, 2R)-1, 2-diphenyl ethanol-bonded on the silica gel (NFcBEs) for high performance liquid chromatography (HPLC), was prepared using γ-glycidoxypropyltrimethoxysilane as coupling reagent. The structure of this novel material was characterized by infrared spectroscopy, elemental analysis and thermogravimetric analysis. Mechanism involved in the chromatographic separation is the multi-interaction including hydrophobic, π-π, hydrogen-bonding, π-charge transfer, dipole-dipole and acid-base equilibrium interactions. Based on these interactions, successful separation could be achieved among polycyclic aromatic hydrocarbons, mono-substituted benzenes, aromatic amines, quinolines, nucleosides, phenols and 5-nitroimidazoles drugs in reversed phase liquid chromatography (RPLC). Good resolutions for substituted amine isomers were also obtained with NFcBEs. Racemates of amino acids and drug carvedilol mixtures were well separated on NFcBEs in the normal phase liquid chromatography (NPLC) mode. Such stationary phase with characteristics of multi-interaction mechanism and mixed-mode separation is potential for the analysis of complex samples. The retention behaviors of R- and S-carvedilol on NFcBEs column were investigated with the assistance of quantum chemistry calculation using the density functional theory (DFT) B3LYP method.

In this paper, a rapid and effective HPLC method, using a new 4-chloro-6-pyrimidinylferrocene-modified silica gel (NFcSi) as a solid-phase extraction (SPE) sorbent, was developed for the purification and determination of trace sulfonamides in foodstuffs. The main influencing factors of SPE including the amount of NFcSi sorbent, sample flow rate, and species and volume of the eluant were investigated and evaluated in a sample pretreatment step. The optimized purification effect was achieved at a sample flow rate of 2 mL min−1 with 100 mg of NFcSi and 5 mL of washing solution (water, 100%). The HPLC analysis was carried out on a Shim-Pack VP-ODS column (150 × 4.6 mm i.d., 5 μm) with a mobile phase of MeOH/0.1% acetic acid–water (30:70, v/v). With a detection wavelength of 270 nm, the good linearities of sulfadimidine (SM2), sulfamethoxazole (SMZ) and sulfadimethoxine (SDM) were obtained at concentrations ranging from 10 to 5000 ng mL−1 (R2 ≥ 0.9998). The RSD% values (n = 6) of retention times and peak areas in intra- and inter-day assays for three sulfonamides were all below 0.55%, 1.80%, 0.20% and 0.78%, which showed good precision. In addition, the overall recoveries of SM2, SMZ and SDM through the extraction and purification steps were in the range of 71.1–86.7%, 70.6–93.6% and 72.4–90.7%. Compared with commercial SPE sorbents, NFcSi featured excellent selectivity to retain polar and nonpolar interferents in sample matrices. The improved method was simple, rapid, accurate and promising for the determination of trace sulfonamides in foodstuffs with complex matrices.

•A mixed-mode stationary phase modified by 4-chloro-6-pyrimidinylferrocene was prepared.•Study of the stationary phase via a linear solvation energy relationship model.•Aromatics, amines, phenols, quinolines, pyridines and nucleosides were employed as probes.•Separation of inorganic anions in anion-exchange mode.•The NFcS column was successfully employed for the analysis of plant growth regulators in Fruit.A novel multi-function and mixed-mode stationary phase based on 4-chloro-6-pyrimidinylferrocene modified silica (NFcS) was synthesized and characterized by infrared spectroscopy, elemental analysis and thermogravimetric analysis. Linear solvation energy relationship method was successfully employed to evaluate the new phase with a set of 27 solutes including aromatic and aliphatic compounds. Multiple mechanisms including hydrophobic, π–π, hydrogen-bonding, charge-transfer, acid–base equilibrium and anion-exchange interactions are involved. Based on these interactions, successful separation could be achieved among polycyclic aromatic hydrocarbons, mono-substituted benzenes, aromatic amines, phenols, quinolines, pyridines and nucleosides in reversed-phase (RP) or normal-phase (NP) chromatography. Inorganic anions were also shown to be individually separated in anion-exchange chromatography by using the same column. Moreover, the results here also demonstrated that NFcS based stationary phase could effectively reduce the adverse effect of residual silanol in the separation process. Such stationary phase with characteristics of multi-interaction mechanism and mixed-mode separation is potential for the analysis of complex samples. The NFcS column was successfully employed for the analysis of plant growth regulators in Fruit.

The associations of nitric oxide (NO) with many diseases are still being discovered, and sometimes, NO levels in the body fluids are too low to be detected. Thus, the determination methods for trace nitrites and nitrates in urine and plasma of healthy volunteers and rheumatoid arthritis (RA) patients are necessary. Using trimethylamine aminated polychloromethyl styrene nano-latex coated capillary column (ccc-TMAPL) and field-amplified sample stacking (FASS) injection, the sensitive open-tubular capillary electrochromatography (OT-CEC) methods for determining trace nitrites and nitrates in urine and plasma of healthy volunteers and RA patients were set up. The limits of detection for both nitrite and nitrate were 1 ng/mL. The intra- and inter-day relative standard deviations (RSDs) of the methods were less than 1.9%, and recoveries were between 89 and 96%. Plasma nitrate (diluted 10 times) levels were 93–301 ng/mL for healthy volunteers and 222–421 ng/mL for RA patients, respectively. Meanwhile, plasma nitrite levels were 7–18 and 40–82 ng/mL, respectively. The urinary nitrite levels were significantly elevated in RA patients. The proposed sensitive FASS-OT-CEC methods for trace nitrites and nitrates hold the promise of practical applications in a wide array of biological analyses, clinical and pathophysiology studies of the diseases related with NO hyperproduction and metabolites.

In this work, a new open-tubular capillary electrochromatography (OT-CEC) method with the nanolatex-coated column was proposed for the determination of nitrites and nitrates in foodstuffs. The method was simple and repeatable as a result of avoiding the introduction of an electroosmotic flow reverse additive (such as cetyltrimethylammonium chloride) in electrophoretic buffer. The limits of quantitation were 0.89 and 1.05 mg kg–1 for nitrate and nitrite, respectively, whereas the overall recoveries ranged from 94 to 103%. The developed OT-CEC method was successfully applied for 12 samples, and the residue profiles of nitrites and nitrates in hams and sausages were obtained and evaluated.