Ionic liquid-based dispersive liquid–liquid microextraction for the determination of formaldehyde in wastewaters and detergents

Abstract

Spectrophotometry in combination with ionic liquid-based dispersive liquid-liquid microextraction (DLLME) was applied for the extraction and determination of formaldehyde in real samples. The method is based on the reaction of formaldehyde with methyl acetoacetate in the presence of ammonia. The variation in the absorbance of the reaction product was measured at 375 nm. An appropriate mixture of ethanol (disperser solvent) and ionic liquid, 1-hexyl-3-methylimidazoliumhexafluoro-phosphate [C(6)MIM][PF(6)] (extraction solvent) was rapidly injected into a water sample containing formaldehyde. After extraction, sedimented phase was analyzed by spectrophotometry. Under the optimum conditions, the calibration graph was linear in the range of 0.1-20 ng mL(-1) with the detection limit of 0.02 ng mL(-1) and limit of quantification of 0.08 ng mL(-1) for formaldehyde. The relative standard deviation (RSD%, n = 5) for the extraction and determination of 0.8 ng mL(-1) of formaldehyde in the aqueous samples was 2.5%. The results showed that DLLME is a very simple, rapid, sensitive, and efficient analytical method for the determination of trace amounts of formaldehyde in wastewaters and detergents, and suitable results were obtained.

Determination of Traces of Ni, Cu, and Zn in Wastewater and Alloy Samples by Flame-AAS after Ionic Liquid-Based Dispersive Liquid Phase Microextraction

“…[22][23][24] It is simple, fast, and does not require large amounts of organic solvents. 25,26 Up to now, the original In situ IL-DLLME is based on the formation of a waterimmiscible IL using a metathesis reaction between a watermiscible IL and anion exchange salt into sample solution.…”

Exploitation of pulsed flows for on-line dispersive liquid–liquid microextraction: Spectrophotometric determination of formaldehyde in milk

“…As they tend to be less harmful to the environment, ILs have replaced organic solvents as extractors in DLLME [11], as demonstrated in the determination of pesticides and metabolites in soils [12], and formaldehyde in beverages [10], wastewater and detergents [13].…”

Desenvolvimento de procedimentos analíticos explorando microextração líquido-líquido em fluxo para a determinação de espécies de interesse em águas e leite

“…Algumas aplicações dos LI como extratores consistem na determinação de pesticidas em solos [29], sulfonamidas em águas [30] consequentemente, apresentem baixa geração de resíduos [31]. Algumas aplicações incluem a extração de pesticidas organofosforados [22], cádmio [23], formaldeído [24] e selênio [25] em amostras de água, além de formaldeído em cervejas e sucos de frutas [26].…”

“…A reação leva à formação de um composto de coloração amarela (3,5-diacetil-1,4-dihidrolutidina) [24] e, para melhorar a sensibilidade, explorou-se a pré-concentração do produto na fase orgânica.…”

“…Entre esses, podem ser citados aqueles que envolvem reação com acetoacetato de metila na presença de amônia [24], com a determinação do produto por espectrofotometria na região do UV (375 nm). Por outro lado, a reação de Hantzsch emprega acetilacetona em meio de acetato de amônio, formando um composto de coloração amarela, que pode ser medido por espectrofotometria na região do visível (412 nm) [79] ou por fluorescência [80].…”