Ring-Oven-Assisted In Situ Synthesis of Metal–Organic Frameworks on the Lab-On-Paper Device for Chemiluminescence Detection of Nitrite in Whole Blood

Abstract

In situ synthesis of metal–organic frameworks (MOFs) on flexible materials for the fabrication of functional platforms and micro-devices is challenging. The time-/precursor-consuming procedure and uncontrollable assembly are stumbling blocks for constructing this platform. Herein, a novel in situ MOF synthesis method on paper substrates by use of the ring-oven-assisted technique was reported. Utilizing the ring-oven’s heating and washing function, MOFs can be synthesized in 30 min on the designated position of paper chips with extremely low-volume precursors. The principle of this method was explained by steam condensation deposition. The MOFs’ growth procedure was theoretically calculated by crystal sizes and the results conformed to the Christian equation. As different MOFs (Cu-MOF-74, Cu-BTB, Cu-BTC) can be synthesized successfully on paper-based chips, the ring-oven-assisted in situ synthesis method has great generality. Then, the prepared Cu-MOF-74 loading paper-based chip was applied to the chemiluminescence (CL) detection of nitrite (NO2 –), based on the catalysis effect of Cu-MOF-74 on the NO2 ––H2O2 CL system. Also, by the delicate design of the paper-based chip, NO2 – can be detected with the detection limit (DL) of 0.5 nM in whole blood samples without sample pretreatment. This work establishes a distinctive method for the in situ synthesis of MOFs and the application of MOFs on paper-based CL chips.

Application of Paper-Based Microfluidic Analytical Devices (µPAD) in Forensic and Clinical Toxicology: A Review

“…The MOF structure catalyzes the conversion from nitrite to oxygen peroxide for CL detection. The detection limit was in the order of subnanomolar concentrations, i.e., 0.5 nM [143]. Although this proof-of-concept work showed interesting characteristics, such as nanomolar sensitivity and suitability for analysis of blood, the complexity of synthesizing the MOF system and the lack of a full validation dramatically limit its practical value.…”

Comparison of the analytical performance of two different electrochemical sensors based on a composite of gold nanorods with carbon nanomaterials and PEDOT:PSS for the sensitive detection of nitrite in processed meat products

“…Numerous analytical methods have been developed for nitrite detection in several sample matrices, such as chromatography, 10,11 spectrophotometry, 12,13 uorescence, 14,15 colorimetry, 16,17 capillary electrophoresis, 18,19 surface-enhanced Raman scattering, 20,21 chemiluminescence, 22,23 and electrochemical sensors. 24,25 Nevertheless, most of the described nitrite detection techniques have limitations, such as hazardous chemical use, sophisticated instrumentation, laborious and complex sample preparation, high cost, and limited selectivity.…”