OBJECTIVE: To establish a high-performance capillary electrophoresis (CE) method for determinating gallic acid in commercial Quanshen pieces of two different colors, amaranth and brownish red. METHODS: CE-UV method was used in the following condition: BGE 20 mmol·L-1 sodium borate solution, voltage 20 kV, detection wavelength 290 nm, sample injection 10 s at 5 kPa, capillary temperature room temperature. RESULTS: A quantitative method was successfully developed to determine gallic acid in Quanshen pieces within 6 min. The contents of gallic acid in 7 batches of amaranth colored Quanshen pieces were 2.70% (Hubei province), 12.08% and 7.79% (Shandong province), 2.01%, 5.78%, 6.97%, and 4.22% (Hebei province), respectively. The contents of gallic acid in brownish red colored Quanshen pieces were 1.35% (Hubei province), 1.81% and 3.42% (Shandong province), 1.87%, 3.42%, 0.44%, and 1.52% (Hebei province), respectively. CONCLUSION: The method is rapid, economical and simple and can provide a powerful quality control measure for Quanshen pieces. The contents of gallic acid in the amaranth colored Quanshen pieces are higher than those in the brownish red colored pieces.

OBJECTIVE: To analyze and characterize the separation effectiveness of self-constructed asymmetrical flow field-flow fractionation system on proteins and lipoproteins, to achieve the optimization of the experimental conditions when separating lipoproteins by orthogonal design test and to investigate the carrier viscosity's influence on separation effectiveness. METHODS: The evaluation of asymmetrical flow field-flow fractionation separation capacity was conducted by using two standard proteins (carbonic anhydrase and thyroglobulin). Under the optimized separation conditions of carbonic anhydrase and thyroglobulin, the channel actual thickness (after assembling, the actual thickness of separation channel was less than initial thickness) was calculated by the analytes' elution time based on the hydrokinetic theory. With orthogonal design test the optimized experimental conditions were studied and statistical analysis was carried on to find out the factors with statistical significance which needed further exploration. RESULTS: According to the hydrodynamics principle and Stoke's function, the channel actual thickness was measured to be 164 μm by separating the two standard proteins, carbonic anhydrase and thyroglobulin, under proper experimental conditions. By the optimization based on orthogonal design test, base-line separation (the resolution had to be higher than 1.50) was achieved. The resolutions of the two experiments were 1.61 and 1.58. According to previous study/ pre-study and supporting theory, in the orthogonal design test, the total 5 factors were integrated for comprehensive investigation: the total flow rate (3.00, 3.50, 4.00, 4.50 mL/min), focus time (3.00, 3.50, 4.00, 4.50 min), transition time (0.5, 1.0, 1.5, 2.0 min), pH of the carrier fluid(6.8, 7.00, 7.20, 7.40) and viscosity of the carrier fluid hydroxypropylmethylcellulose concentration: 0.00%, 0.03%, 0.06%, 1.00%). Among the 5 factors, viscosity was found to have the statistical significance on separation effectiveness which was further investigated. The resolution of high density lipoprotein and low density lipoprotein was increased by the increasing viscosity which also caused more obvious negative spikes. CONCLUSION The separating capacities of self-constructed asymmetrical flow field-flow fractionation system on lipoproteins were verified to be effective and an optimized experimental condition was found to achieve the base-line separation of high density lipoprotein and low density lipoprotein. Viscosity of the carrier fluid was proved to have the statistical significance on lipoprotein separation.
Fractionation, Field Flow ; Lipoproteins ; Lipoproteins, LDL