Porphyrins have planar and conjugated structures, good optical properties, and other special functional properties. Owing to these excellent properties, in recent years, porphyrins and their analogues have emerged as a multifunctional platform for chemical sensors. The rich chemistry of these molecules offers many possibilities for metal ions detection. This review mainly discusses two types of molecular porphyrin and porphyrin composite sensors for metal ions detection, because porphyrins can be functionalized to improve their functional properties, which can introduce more chemical and functional sites. According to the different application materials, the section of porphyrin composite sensors is divided into five sub-categories: (1) porphyrin film, (2) porphyrin metal complex, (3) metal–organic frameworks, (4) graphene materials, and (5) other materials, respectively.

MIL-100(Fe, Cr) and MIL-101(Cr) were synthesized by the hydrothermal method and applied to the adsorptions of five aromatic amines from aqueous solutions. These three metal-organic frameworks (MOFs) were well characterized by powder X-ray diffraction (PXRD), scanning electron microscope (SEM), transmission electron microscope (TEM), thermogravimetric analysis (TGA) and surface area analysis. The adsorption mechanism of three MOFs and the effects of the structures of MOFs on the adsorption of aromatic amines were discussed. The results show that the cavity system and suitable hydrogen bond acceptor were important factors for the adsorption for five aromatic amines of aniline, 1-naphthalamine, o-toluidine, 2-amino-4-nitrotoluene and 2-nitroaniline: (a) the saturated adsorption capacity of aniline, 1-naphthylamine and o-toluidine on MIL-100(Fe) were 52.0, 53.4 and 49.6 mg/g, respectively, which can be attributed to the intermolecular hydrogen bond interaction and cavity system diffusion. (b) The adsorption capacity of 2-nitroaniline and 2-amino-4-nitrotoluene on MIL-101(Cr) were 54.3 and 25.0 mg/g, respectively, which can be attributed to the more suitable pore size of MIL-101(Cr) than that of MIL-100(Fe, Cr). The MOFs of MIL-100(Fe) and MIL-101(Cr) can be potential materials for removing aromatic amines from aqueous solutions.

To prepare immunomodulation peptides from rice protein hydrolysates (RPHs), trypsin was employed for enzymatic hydrolysis, and the immunomodulating activities of RPHs were studied using mouse peritoneal macrophage proliferation assay. The peptide fractions with the highest activity were further purified using macroporous adsorption resin, strong cation-exchange chromatography, gel filtration chromatography and reversed-phase high-performance liquid chromatography. The peptide sequence was identified as Tyr-Gly-Ile-Tyr-Pro-Arg (YGIYPR) by high-performance liquid chromatography electrospray ionization quadrupole time-of-flight mass spectrometer. Evaluating its immunomodulatory activity showed that YGIYPR enhanced the proliferation of macrophage RAW 264.7 cells in the range of 12.5–100 μg/mL, and even a minimum dose achieved good proliferation. The results demonstrated that the RPHs prepared by trypsin could serve as a source of immunomodulating peptides and the immunomodulatory peptide YGIYPR is a potential natural ingredient for manufacture of functional foods or health care products. Abbreviations: RP-HPLC: Reversed-phase high-performance liquid chromatography; HPLC-ESI-Q-TOF MS: High-performance liquid chromatography electrospray ionization quadrupole time-of-flight mass spectrometer; YGIYPR: Tyr-Gly-Ile-Tyr-Pro-Arg; RP: Rice protein: RPHs: Rice protein hydrolysates; MAR: Macroporous adsorption resins; TFA: Trifluoroacetic acid; MW: Molecular weight; SI: Stimulation index; DMSO: Dimethyl sulfoxide; MTT: 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide.