Development of Flow Injection Spectrophotometric Method for 1-Napthylthiourea Using Sodium Nitrite and Sulphanilic Acid Diazotization Reaction

A simple spectrophotometric method in conjunction with flow injection analysis is developed for the quantitative analysis of 1-napthylthiourea (ANTU). The reaction is based on the alkaline hydrolysis of ANTU to 1-naphthylamine at 30°C, coupled with diazotized sulphanilic acid resulting in 4-(sulphophenylazo)-1-naphthylamine which is monitored at 495 nm. The limit of detection (S/N = 3) is 0.01 mg/L with a sampling throughput of 45/h. The method is linear over the range of 0.05–120 mg/L (R2=0.9995,n=7), with calibration equation y = 0.031x−0.018 (y = absorbance; x = mg/L) and relative standard deviation (n=3) 1.8–3.6%. Experimental variables are optimised, and the interfering effects of different pesticides, organic compounds, cations, and anions at environmentally relevant concentrations are investigated. The analysis of ANTU in spiked water samples is extracted with solid phase procedure using disposable Sep-Pak C18 cartridges, and the recovery was 93 ± 1.9–110 ± 3.0%. The results of the proposed method are compared with the HPLC method by applying the F-test and paired Student t-test at 95% confidence level.

Investigation on growth, optical, thermal, mechanical, dielectric, LDT studies of sulphanilic acid monohydrate: A promising third-order nonlinear optical material

An organic nonlinear optical centric single crystal, sulphanilic acid monohydrate (SAM) was successfully grown by slow evaporation method. The cell parameters of the grown crystal were assessed by single crystal XRD. The UV absorption edge was found to be 249[Formula: see text]nm providing a wide optical transmittance covering the visible region. The thermal, mechanical and dielectric properties of the grown crystal were examined. Fluorescence emission spectrum was recorded and lifetime was studied. A multiple shot laser technique was adopted to investigate the surface laser damage of the crystal. The third-order nonlinear optical characteristics of the grown crystal, investigated by [Formula: see text]-scan technique attest its suitability in the field of nonlinear optical applications.

Sulphanilic acid as a recyclable bifunctional organocatalyst in the selective conversion of lignocellulosic biomass to 5-HMF

We herein report an unprecedented integrated process using organic salts as bifunctional organocatalysts under absolutely metal-free conditions for the conversion of a wide range of biomass-derived carbohydrates, cellulose, and even untreated lignocellulose (e.g. straw and barley husk) into 5-hydroxymethylfurfural (5-HMF).