The Research On Determination Of Formaldehyde And Formaldehyde Sensor

Formaldehyde is an extremely important industrial raw material duo to its chemical activity, high purity and relative cheapness. On the other hand, formaldehyde-containing construction and. furnishing materials are extensively used in modern building and furniture. Owing to its high toxicity and possible carcinogenic properties, formaldehyde is now recognized as one of the most important pollutants in both workplace and ambient atmosphere. Determination of formaldehyde plays an important role in many areas. Silica gel is typical porous sorbent, is usually used as catalytic carrier. Here we report the fluorescent sensor system for formaldehyde visualization, consisting of Nash reagent selected as formaldehyde recognition element and silica gel beads as its carrier. And novel spectrophotometric method with silica gel beads for determination of formaldehyde has also been discussed.1 We report here the fluorescent sensor system for formaldehyde visualization, consisting of Nash reagent as formaldehyde recognition element and silica gel beads as its carrier. And its response performance toward formaldehyde has also been investigated. The sensor dynamic response range can vary from 0.1 to 0.8μg/mL formaldehyde. If a commercially available light-emitting diode (LED) is used as a light source, this system is an effective naked-eye-detectable formaldehyde sensor under aqueous-phase condition. We also show that this system may be used to extract and detect formaldehyde colorimetrically in a two-phase aqueous-ambient set-up, where formaldehyde being detected were originally present in the air. It has demonstrated a high selectivity to formaldehyde with no response to methanol, ethanol, acetone, and other common organic compounds.2 A novel method is described for the determination of formaldehyde based on Hantzsch reaction, which involves the cyclization of acetic ammonium, formaldehyde and 2, 4-pentanedione(PD) in Nash's reagent to form a yellow compound 3, 5-diacetyl-l, 4-dihydrolutidine(DDL) at pH of 6. Silica gel beads are added into thereaction solution to significantly reduce the time of achieving the stable color. The silica gel beads not only catalyze the reaction process, but also increase the sensitivity of the analysis. Compared to the standard method, the proposed method can be operated simply and easily without heating. Furthermore, the reaction and measurement can be carried out at the same time. Thus the proposed method is potential to be used to make a monitoring sensor for formaldehyde.3 The papers describe the synthesis of 3,5-diacetyl-l,4-dihydrolutidine (DDL) and its new application for detection of Hg(II). The response of the method is based on the absorbance quenching of DDL by reaction with Hg( II). The method exhibits a linear response toward Hg(II) in the concentration range 5.0 ×10-10-5.0×10-6 mol.L-1. The proposed method revealed very good selectivity for Hg(II) over a wide variety of other metal ions.