Miniaturized solid-phase extraction as a sample preparation technique for the determination of phthalates in water

Abstract

Miniaturized solid-phase extraction (SPE) has been developed and successfully employed for the determination of organic species in water samples by liquid chromatography (LC). The method is based on the concept of a microscale extraction technique using a fused-silica capillary column for gas chromatography (GC), so-called in-tube solid-phase microextraction (SPME). The extraction conditions, such as the extraction time and flow-rate for the extraction and desorption process, were investigated as well as the effect of the internal structure of the extraction capillary on the efficiency. By inserting a stainless steel wire into the extraction capillary to reduce the internal volume of the capillary with the same surface area of the coating, an improved extraction and pre-concentration effects were obtained. Further pre-concentration was accomplished by the extraction device with a novel fiber-in-tube configuration. The direct coupling of the extraction method with a LC system has made it possible to determine low levels of phthalates in water samples without high consumption of organic solvents. The system developed must have potential applications for the analysis of environmental and biological samples in aqueous sample matrices.

Simultaneous determination of seven phthalates and four parabens in cosmetic products using HPLC‐DAD and GC‐MS methods

“…As shown in Table 3, the optimum recovery of the studied compounds occurred when the LC-C18 column was conditioned with methanol, water, 40% methanol aqueous solution, washed with 40% methanol aqueous solution, and eluted with methanol. The main differences in sample preparation procedure between 96/45/EC [19] and the current method are listed in Table 4. In contrast to the 96/45/EC method, methanol was used as extractant instead of H 2 SO 4 /EtOH/H 2 O solution.…”

“…On comparing the HPLC chromatograms recorded at 230 nm and 260 nm, 230 nm was selected for quantification studies. As listed in Table 4, deviating from the 96/45/EC method [19], a water-methanol gradient elution system was used as mobile phase instead of a THF/H 2 O/CH 3 OH/ CH 3 CN solution, while the C18 column was replaced by a C8 column for separation. Current separation conditions satisfied requirements for the simultaneous separation of phthalates and parabens.…”

High-Temperature Separations on a Polymer-Coated Fibrous Stationary Phase in Microcolumn Liquid Chromatography

“…[9][10][11][12][13][14] By introducing fine fibrous materials as the extraction medium, several novel microscale sample preparation techniques were developed based on excellent resistance to typical organic solvents. [15][16][17][18][19][20][21][22] These fibrous materials were also employed as a stationary phase in GC, because of their excellent thermal stability over the temperature range typically used in most of GC separations. [23][24][25][26][27] Coated with typical polysiloxane-based materials onto the surface of the fibrous materials, the retentivity was significantly improved, and also the selectivity could be designed on the basis of the type of polymeric coatings.…”

Multi-walled carbon nanotubes packed cartridge for the solid-phase extraction of several phthalate esters from water samples and their determination by high performance liquid chromatography

“…So far, various methods such as liquid-liquid extraction (LLE) [7][8][9], solid-phase extraction (SPE) [10][11][12][13][14], and solid-phase microextraction (SPME) [15][16][17][18][19][20] have been employed as sample pretreatment procedures for the determination of phthalate esters. Among above mentioned sample pretreatment procedures, solid-phase extraction based on the use of different types of adsorbents such as C 18 [7], C 8 [14], PS-DVB [11][12][13][14], and hydroxylated PS-DVB polymers [12] is the most widely used one.…”