2-Aminoterephthalic Acid

Single crystals of the title compound, C(10)H(11)NO(4), an inter-mediate in the industrial synthesis of yellow azo pigments, were obtained from the industrial production. The mol-ecules crystallize as centrosymmetic dimers connected by two symmetry-related N-H⋯O=C hydrogen bonds. Each mol-ecule also contains an intra-molecular N-H⋯O=C hydrogen bond. The dimers form stacks along the a-axis direction. Neighbouring stacks are arranged into a herringbone structure.

An effective magnetic solid-phase extraction method was proposed using magnetic graphene oxide coated with poly(2-aminoterephthalic acid-co-aniline) as a sorbent for preconcentration and extraction of organophosphorus pesticides from environmental water and apple juice samples, and determined using the gas chromatography-mass spectrometry analysis. To approve the successful synthesis of the magnetic nanocomposite, the prepared sorbent was characterized by field emission scanning electron microscopy, X-ray diffraction, vibrating sample magnetometer, and Fourier transforms infrared techniques. The main parameters affecting the extraction efficiency were considered and studied to afford an optimized procedure. Systematic method validation verified its suitable recoveries (89.4-107.3%), and precision (relative standard deviations < 6.8%). The method showed a wide linear dynamic range (0.04-700 ng/mL) with low limits of detection (0.01-0.06 ng/mL) and quantification (0.04-0.21 ng/mL). This method presented good potential and great sensitivity for the pesticides determination.

In this study, we developed a simple and economical method for the green synthesis of Cu2+ sensors based on betaxanthin pigments. Aminoisophthalic acid-betaxanthin was synthesized by coupling 2-aminoisophthalic acid and betalamic acid produced from DOPA-extradiol-4,5-dioxygenase in situ and in vitro. The resulting 2-aminoterephthalic acid-betaxanthin (2-AIPA-BX) presented a satisfying fluorescence quantum yield in water and a high degree of selectivity for Cu2+ over interfering metal ions. The bioproduction process of 2-AIPA-BX was scaled up from test tubes to 1 L-flasks, indicating the robustness and reproducibility of this method. Additionally, we successfully incorporated 2-AIPA-BX into paper-based analytical devices to facilitate simple, inexpensive, and portable setup with lower sample consumption for onsite monitoring of environmental and biological samples.