A comprehensive undergraduate experiment： development of a dispersive solid-phase extraction method based on halogen-bonded organic frameworks and its application to the analysis of brominated flame retardants

doi:10.3724/SP.J.1123.2026.04016

Abstract

Abstract:

To address the evolving demands for innovation and practical competencies in pharmaceutical education， and in alignment with the “student-centered， outcome-driven” pedagogical approach， our teaching team has undertaken a comprehensive reform of the Pharmaceutical Analysis curriculum. We designed and implemented an integrative， research-based laboratory experiment for undergraduate students. Centered on the design and application of functional materials， the experiment guides students through the independent synthesis of a halogen-bonded organic framework， designated as XOF-1， followed by systematic structural characterization， performance evaluation， and analytical application. The experiment is grounded in real-world environmental analysis challenges， requiring students to employ the synthesized material as a dispersive solid-phase extraction （DSPE） adsorbent for the selective enrichment of typical brominated flame retardants， including tetrabromobisphenol A （TBBPA）， tetrachlorobisphenol A （TCBPA）， and hexabromobenzene （HBB）， and to achieve the removal of TBBPA from actual water samples. The instructional process fully encompasses the workflow from material preparation and structural characterization to method development and performance assessment， enabling students to experience a complete research pathway from material design to practical application. This approach immerses them in the scientific inquiry cycle of theory-design-experiment-analysis. Through this experiment， students gain solid proficiency in synthesizing and characterizing functional materials and applying them to sample pretreatment. By engaging in experimental design， condition optimization， and data interpretation， they develop critical thinking， problem-solving skills， and capacity for independent inquiry. The exercise fosters deep integration of theoretical knowledge and practical skills， stimulates research interest， strengthens innovative and applied mindsets， and cultivates a sense of professional responsibility in environmental and public health. Ultimately， it achieves a cohesive blend of knowledge acquisition， competency development， and value cultivation， fulfilling the overarching goal of holistic education through experimental learning.

Key words: comprehensive experiment, pharmaceutical analysis, halogen-bonded organic frameworks, dispersive solid-phase extraction, brominated flame retardants

CLC Number:

O658

WANG Dandan, HU Jiaqi, QIN Cui, WANG Mingyue, KE Famin, NIU Hong, YANG Xilin, GAO Die. A comprehensive undergraduate experiment： development of a dispersive solid-phase extraction method based on halogen-bonded organic frameworks and its application to the analysis of brominated flame retardants[J]. Chinese Journal of Chromatography, 2026, 44(10): 1251-1261.

Figures/Tables 10

Fig. 1 Structures of TBBPA， TCBPA and HBBTBBPA： tetrabromobisphenol A； TCBPA： tetrachlorobisphenol A； HBB： hexabromobenzene.

Fig. 2 Schematic diagram of the experimental design TPy： 1，3，5-tri（4-pyridyl）benzene； CHCl3：chloroform； MeOH： methanol； AgOTf： silver（Ⅰ） trifluoromethanesulfonate； DSPE： dispersive solid-phase extraction.

Fig. 3 X-ray diffraction （XRD） pattern of XOF-1

Fig. 4 （a） SEM and （b） TEM images of XOF-1

Fig. 5 （a） FT-IR spectra and （b） 1H NMR spectra of TPy and XOF-1

Fig. 6 （a） TGA curve and （b） zeta-potentials under different pH values of XOF-1

Fig. 7 Water contact angle image of XOF-1

Fig. 8 （a） Adsorption isotherms and （b） adsorption kinetic curves of the three target analytes （n=3） Q： adsorption capacity.

Fig. 9 Effects of （a） adsorbent dosage，（b） pH and （c） NaCl concentration on the adsorption efficiency of XOF-1； effects of （d） desorption solvent，（e） desorption time and （f） desorption frequency on the desorption efficiency of XOF-1 （n=3） CH2Cl2： dichloromethane； THF： tetrahydrofuran； ACN： acetonitrile.

Table 1 Adsorption recoveries of TBBPA in real water samples with XOF-1 （n=3）

Sample	Initial/（μg/mL）	Final/（μg/mL）	Recovery/%	RSD/%
Tap water	9.46	7.76	82.19	4.93
	25.01	18.27	73.06	0.84
	52.97	32.52	61.39	1.16
Pond water	8.80	6.57	74.66	1.56
	25.72	22.31	86.74	4.27
	52.10	36.27	69.62	0.32
River water	10.05	8.43	83.86	1.01
	21.02	14.38	68.42	1.21
	51.50	31.88	61.91	2.22

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