ABSTRACT
A novel miniaturized CE with amperometric detection (mini-CE-AD) method has been developed for fast determination of aliphatic aldehyde preservatives, namely formaldehyde and glyoxal, in commodities. After derivatization with an electroactive compound 2-thiobarbituric acid, these two nonelectroactive aldehydes were converted to electroactive adducts, therefore detectable by mini-CE-AD approach. Under the optimum conditions, two aldehydes can be well-separated with the coexisting interferents as well as their homologs (acetaldehyde and methyl-glyoxal), and the LODs (S/N = 3) were achieved at nanogram-per-milliliter level (1.64-2.80 ng/mL) based on the online enrichment method of transient moving chemical reaction boundary. The proposed method has been applied for the analyses of above aldehyde preservatives in different real commodity samples including skincare products, baby lotion, and toothpaste, and the average recoveries were in the range of 94-105%, which should find a wide range of analytical applications as an alternative to conventional and microchip CE approaches.
Subject(s)
Aldehydes/analysis , Electrophoresis, Capillary/instrumentation , Electrophoresis, Capillary/methods , Miniaturization/instrumentation , Preservatives, Pharmaceutical/analysis , Cosmetics/chemistry , Limit of Detection , Linear Models , Reproducibility of ResultsABSTRACT
A hollow-fiber liquid-phase microextraction (HF-LPME) method has been developed for the preconcentration of trace sulfonamides in water samples. Six commonly used sulfonamides including sulfamethazine (SMZ), sulfamerazine (SMR), sulfadiazine (SDZ), sulfadimethoxine (SDM), sulfamethoxazole (SMX), and sulfathiazole (STZ) were determined by CE with electrochemical detection (CE-ED) after microextraction. Several factors that affect extraction efficiency, separation, and detection were investigated. Under the optimum conditions, above sulfonamide compounds could achieve baseline separation within 35min, exhibiting a linear calibration over three orders of magnitude (r(2)≥0.998); the obtained enrichment factors were between 121 (for SDZ) and 996 (for SDM), and the LODs were in the range of 0.033-0.44ng/mL. The proposed HF-LPME/CE-ED method has been applied for the sensitive analyses of the real-world water samples with recoveries in the range of 75.1-109%.