Quantitative TLC-Image Analysis of Urinary Creatinine Using Iodine Staining and RGB Values

Green one-step synthesis of mushroom-derived carbon dots as fluorescent sensors for Fe3+ detection

Blue photoluminescent carbon dots were synthesized from Lentinus polychrous Lèv. via a simple hydrothermal process without additional chemical reagents or functionalization. The carbon dots (hereafter referred to as LCDs) were quasi-spherical with an average diameter of 6.0 nm. The strong fluorescence emissions of LCDs were utilized as the basis of efficient turn-off probes for Fe3+. The quenching phenomenon could be used to rapidly determine Fe3+ concentrations in the range of 0.0-2.0 mM in aqueous solution, with a limit of detection (LOD) of 16 μM. In the presence of interference, LCDs demonstrated good sensitivity and selectivity towards Fe3+ in both solution-based and paper-based systems. The LCDs also exhibited excellent photostability and an eco-friendly nature, making them an ideal choice for environmental monitoring with significant potential for diagnostic applications.

Development of a Novel Tear Lipid Test Strip

PURPOSE

The unifying characteristic of dry eye is the loss of tear film homeostasis, and the tear lipid layer is a key component for maintaining film stability. The detection of tear lipid is of great significance for the diagnosis of dry eye. In this study, we explored a new test strip for the detection of tear lipid.

METHODS

The tear lipid test strip was prepared by coating the strip material with hydrophobic nano-silica. We tested its physical properties with iodine vapor chromogenic and cobalt chloride test methods. Its biosafety was evaluated by an ocular irritation test in rabbits. Finally, we established a rabbit meibomian gland dysfunction model and measured both eyes with the tear lipid test strip at the first, third, seventh, 14th, 16th, and 21st day after surgery.

RESULTS

The tear lipid test strip had fine lipophilicity and hydrophobicity. It can extract lipid from tear, and the tear lipid can be quantified by measuring the length of lipid infiltration. In the ocular irritation test, the test strip had no obvious eye irritation. The length of lipid infiltration between experimental and control rabbit eyes began to show statistical difference since the third day after surgery.

CONCLUSIONS

The novel tear lipid test strip has great lipophilicity, hydrophobicity, and biological safety. It might be effectively applied in diagnosis of dry eye.

Digitally enhanced thin layer chromatography for simultaneous determination of norfloxacin and tinidazole with the aid of Taguchi orthogonal array and desirability function approach: Greenness assessment by analytical Eco-Scale

In this study, an eco-friendly fast simple method was developed for simultaneous determination of norfloxacin and tinidazole based on thin-layer chromatography and image-processing analysis. The binary mixture was separated using reversed phase - thin layer chromatography plates and 30% trifluoroacetic acid only as mobile phase. Mobile phase composition was optimized using Taguchi orthogonal array and Derringer's desirability function. The plates were viewed under UV lamp and photographed by iPhone camera followed by image processing with Fiji software using integrated density as the measured response. As decreasing illumination increases the sensitivity of the method, this method was applied on two different ranges for each drug. The first one was 0.6-6.0 and 0.9-9.0 µg/spot for norfloxacin and tinidazole, respectively measured on the original image with normal illumination. The second one was measured after decreasing the illumination of the captured images at 0.06-0.60 and 0.09-0.90 µg/spot for norfloxacin and tinidazole, respectively. The proposed method was successfully applied for the determination of both drugs in tablets dosage form without interference from the commonly encountered excipients. Analytical Eco-Scale was used to evaluate the greenness profile of the proposed method and it was found to be excellent green analytical method.