Carminic acid (CA) extracted from cochineal is widely used in food additives as a natural colorant, and its potential risk to human health makes its detection important. In this work, a layered doubled hydroxide (LDH)–luminol–H2O2 system-based chemiluminescence (CL) platform has been successfully applied for CA sensing. The principle detection consists of two steps: first, LDH adsorbs CA onto the surface via electrostatic attraction; second, CA quenches the CL of the LDH–luminol–H2O2 system via the synergistic effect of CL resonance energy transfer, reduction of reactive oxygen species, and occupation of positively charged centers of brucite-like layers. With this CL approach, 0.5 μM CA is detectable using a CL spectrometer, and the limit of detection is 0.03 μM. This CL system exhibited a linear response to CA in the concentration range from 0.5 to 10 μM. In addition, the practical application of the designed CL sensing system is evaluated with dried pork slice samples.
We present here a novel strategy for textile sample treatment, using galvanic displacement-based substrates, to identify anthraquinone dyes by surface enhanced Raman spectroscopy (SERS). This global procedure of SERS analysis, using several silver microparticles , in particularly those of dendritic shape, formed by reducing silver nitrate with zinc or copper, can be accomplished within 20 min. Compared to the synthesis of standard Lee-Meisel colloids, the preparation of silver dendrites provides a simple, fast and cost-effective route to produce reliable SERS substrates. The most fascinating feature is that the textile fibers analyzed are almost simultaneously covered with the substrates once the galvanic displacement reaction is triggered. This method was successfully applied to discriminating between alizarin and purpurin in a 6th-9th century samite with bird roundels, and carminic acid and laccaic acid in a 1740s chinoiserie brocade. However, as is the case with other silver substrates, the Raman signals of the insect dyes normally overlapped those of the plant dyes in the SERS profiles.
危险品化学品经营许可证（带存储）