Tablet‐effervescence‐assisted dissolved carbon flotation for the extraction of four triazole fungicides in water by gas chromatography with mass spectrometry

Abstract

A pretreatment method named tablet-effervescence-assisted dissolved carbon flotation was introduced for the determination of four triazole fungicides in environmental water. In this method, the use of effervescent tablet composed of nontoxic sodium carbonate and sodium dihydrogen phosphate could generate CO in situ to assist the dispersion of extraction solvent and to accelerate mass transfer of target analytes. In addition, the simple phase separation simply based on the rising of low-density organic solvent from the aqueous phase was applied rather than the application of apparatus, which demonstrated the potential for on-site extraction in the field. The experimental variables, including the composition of effervescent tablets, amount of effervescent tablets, types and volume of extraction solvent, were investigated. Under the optimized conditions, the method showed good linearity for myclobutanil, tebuconazole, epoxiconazole, and difenoconazole in the range of 1-100 μg/L. The limits of detection and the limits of quantification were within the range of 0.15-0.26 and 0.49-0.86 μg/L, respectively. The obtained correlation coefficients varied from 0.997 to 0.999, and suitable enrichment factors were 422-589. The recoveries were 82.5-112.9% with relative standard deviations of 4.7-13.5%.

Self‐acidity induced effervescence and manual shaking‐assisted microextraction of neonicotinoid insecticides in orange juice

“…The appropriate type of the effervescent agent plays a crucial factor in the formation of CO 2 bubbles which promptly disperses the extractant and provides great intensity of effervescence, resulting in an effective transfer of analytes to the extractant . For this purpose, various types of the carbonate or bicarbonate reagent as the CO 2 source were tested.…”

“…This is a new version of microextraction in which no dispersive solvent or energy force is required instead of vortex, ultrasound, or aspirating‐expelling air‐assisted DLLME . An effervescent pair consisting of a proton donor and carbon dioxide source is used to produce CO 2 as the assistance for extractant dispersion in the aqueous media . The effervescent reaction is commonly carried out by either preparing a pressed tablet or adding the acid and alkaline reagents one by one; however the pre‐production of a tablet or chemical materials can be tedious and expensive .…”

Microwave‐assisted‐demulsification dispersive liquid–liquid microextraction for the determination of triazole fungicides in water by gas chromatography with mass spectrometry

“…The main disadvantages of LLE are using of some toxic organic solvents, time consuming, tedious operation, and low enrichment factor (EF). SPE has higher EF than LLE but it requires device conditioning and elution with large volumes of organic solvents .…”

“…in 2006 . Recently, a variety of improved DLLME methods have been developed for determination of triazole pesticide residues, such as air‐assisted dispersive liquid–liquid microextraction (AA‐DLLME) , coupling stir bar sorptive extraction with dispersive liquid–liquid microextraction , DLLME based on solidification of floating organic droplet , vortex‐assisted ionic liquid dispersive liquid–liquid microextraction , ultrasound assisted salting‐out homogenous liquid–liquid microextraction , homogenous liquid–liquid extraction based on a narrow‐bore tube , and effervescence‐assisted dispersive liquid–liquid microextraction . However, in most traditional DLLME, the extractant was usually a water‐insoluble organic solvent with a density greater than that of water, and simple phase separation was carried out by centrifugation.…”

“…And only a few types of organic solvents met these requirements and most of them were toxic halogenated hydrocarbon reagents . These methods mentioned above need centrifugation to break the emulsion, except for the methods that use homemade narrow‐bore tube and effervescence‐assisted demulsification . Due to the limitation of the centrifuge in analytical laboratory, the traditional centrifugal approach cannot enlarge the volumes of the tested sample.…”