New macroporous polymers have been prepared based on two different “platforms” to simplify rather complicated pretreatment processes for LC analyses. For example, uniformly sized, molecularly imprinted polymer particles modified with sulfonic acids on outer surface easily removed humic acids in environmental water sample to improve detectability of really low level of the target molecule. Nicely controlled, 3D skeletal co−continuous polymers (monolithic polymer) have been prepared using visco−elastic phase separation mechanism as well as the utilization of epoxy monomers and a diamine. In addition, a hydrophilic monolithic media based on ethylene oxide units simplified affinity chromatography through avoiding non−specifically bound proteins even if those were utilized in protein lysate. All the macroporous polymers have contributed to simple and accurate LC analyses.
Needle−type extraction devices have been developed for the simple andsensitive determination of gaseous volatile organic compounds (VOCs) in gas chromatography (GC). The needle−type extraction device allows direct insertionoftheextraction medium into the GC injection port, therefore, simple and rapid desorption of the extracted analytes could be achieved. For simultaneous derivatization and preconcentration of VOCs, fiber−packed needle was developed. The fiber−packed needle was prepared with a bundle of fine filaments typically coated with methyl−polysiloxane. During the extraction, target analytes, such as volatile aldehydes or ethylene oxide, were simultaneously derivatized and concentrated in the extraction needle.Particle−packed needle has been developed for the extraction of VOCs commonly found in environmental gaseous samples. Several particulate materials, such as porous polymer particles or activated carbon, were employed as the extraction media for the respective target analytes. The particle−packed extraction needle was successfully appliedforvarious analytical situations, such as in−door air analysis, fire investigation and human breath analysis.
Anew inkjet sample introduction method was developed for capillary electrophoresis (CE). This system could control the exact volume of ejected liquid with high accuracy and precision at the picoliter level. The single droplet volume of 1×10－6 mol/L dopamine (DA) in 1×10－2 mol/L borate buffer and in the 40 times diluted serum were 240 pL and 243 pL,respectively. Sample droplets were ejected by stressing a piezoelectric slice stuck on the extrusion chamber. The pulse voltages wereappliedtothepiezoelectric slice which made the slice deformed. Using this method, DA and epinephrine (EP) were separated and the concentration of EP in serum was determined at 5.88×10－7 mol/L, DA was not detected. The recovery (n＝3) of EP and DA added to serum were in the range of 95.8−98.7%, and 97.5−103.4% respectively, which showed good accuracy and reproducibility.