Advances in liquid-phase microextraction technology and its application in biological sample pretreatment / 药学学报

Liquid-phase microextraction is a novel pretreatment technique for biological samples developed on the basis of liquid-phase extraction technology, which is simple, rapid, economical, and environmentally friendly, and has been widely used in the analysis of biological matrix samples such as blood, urine, and saliva. In this paper, we review the basic principles of the main modes of liquid-phase microextraction techniques, i.e., single-drop microextraction, dispersive liquid-liquid microextraction, and hollow-fiber liquid-phase microextraction, and the progress of their applications in biological sample pretreatment by reviewing the literature in the past five years, with a view to providing technical support and reference for sample pretreatment in the fields of in vivo drug analysis, pharmacokinetic studies and new drug development.

Desirability Function in analytical method development for determination of glitazones and metabolites employing HF-LPME

Abstract Thiazolidinedione, often shortened to TZD or glitazone, helps lower insulin resistance, which is the underlying problem for many people with type 2 diabetes. The two most known glitazones are pioglitazone (PGZ), with the brand name medicine Actos®, and rosiglitazone (RSG), which is Avandia®. This study presented a multivariate optimization in the microextraction procedure employing Fractional Factorial Design (FFD) combined with Desirability Function (DF) to determine TZD and metabolites in biological samples. Microextraction requires several parameters to be optimized; however, most of them still use univariate optimization. Finding optimum conditions by simple response is relatively simple, but the problems, in case of microextractions, are often more complex when it has more responses. For example, changing one factor that promotes one response may suppress the effect of the others. Thus, this multivariate optimization was applied for two bioanalytical methods for determination of TZD and metabolites, one by HPLC and other by CE, both using Hollow Fiber Liquid-Phase Microextraction (HF-LPME). The results establish the optimal values and elucidate how the factors that affect HF-LPME procedure perform in extraction efficiency for TZDs. Additionally, this study demonstrates that DF can be an important tool to optimize microextraction procedures.

Content Determination of Pulegone in Schizonepeta tenuifolia and Its Compound Preparation by Hollow Fiber Liquid-phase Microextraction Coupled with HPLC / 中国药房

OBJECTIVE：To establish t he metho d for the content determination of pulegone in Schizonepetae tenuifolia decoction pieces and its compound preparation. METHODS ：Hollow fiber liquid-phase microextraction coupled with HPLC （HF-LPME-HPLC） was adopted. Based on single factor tests ，HF-LPME condition of S. tenuifolia decoction pieces and its compound preparation （taking Compound S. tenuifolia granule as an expample ） was optimized by central composite design-response surface methodology using pulegone enrichment multiple as index ，with the concentration of sample phase solution （NaCl），extraction time and stirring speed as factors. Validation test was conducted. HPLC method was adopted to determine the content of pulegone. The determination was performed on Hypersil C 18 column with mobile phase consisted of methanol- 0.3％ phosphoric acid （gradient elution ）at the flow rate of 1.0 mL/min. The detection wavelength was set at 252 nm，the column temperature was 25 ℃. The sample size was 20 μL. The feasibility of HF-LPME-HPLC method established in this study was validated by using HPLC method stated in the item of S. tenuifolia decoction pieces in 2020 edition of Chinese Pharmacopoeia （part Ⅰ）as reference. RESULTS ：The optimum HF-LPME conditions included n-nonanol as the extraction solvent ，sample phase solution with 11％ NaCl and pH value of 7，stirring speed of 800 r/min，extraction time of 36 min. Results of HPLC methodology investigation showed that linear range of pulegone were 0.05-5 μg/mL（r＝0.999 0）. The limits of detection and quantitation were 0.4 and 1.3 ng/mL，respectively. RSDs of intra-day and inter-day precision were 1.8％-4.0％ and 1.5％-4.1％（n＝3），respectively. RSDs of reproducibility and stability tests （24 h）were all lower than 8％（n＝6）. Average recoveries of S. tenuifolia decoction pieces and Compound S. tenuifolia granule were 102.6％-105.1％ and 97.2％-102.3％，respectively；RSDs were not higher than 4.1％ and 6.2％（n＝3）. The average contents of pulegone in S. tenuifolia decoction pieces determined by pharmacopoeia method and established method were 0.84 mg/g（RSD＝4.3％ ，n＝3）and 0.87 mg/g（RSD＝5.5％ ，n＝3），respectively，with no significant difference （P＞0.05）. CONCLUSIONS ：The established HF-LPME-HPLC method can enrich and concentrate pulegone ， shows strong purification ability and high sensitivity ，and can be used to determine the contents of pulegone in S. tenuifolia decoction pieces and its compound preparation.

Hollow fiber-based liquid phase microextraction followed by analytical instrumental techniques for quantitative analysis of heavy metal ions and pharmaceuticals / 药物分析学报

Hollow-fiber liquid-phase microextraction (HF-LPME) and electromembrane extraction (EME) are miniaturized extraction techniques, and have been coupled with various analytical instruments for trace analysis of heavy metals, drugs and other organic compounds, in recent years. HF-LPME and EME provide high selectivity, efficient sample cleanup and enrichment, and reduce the consumption of organic sol-vents to a few micro-liters per sample. HF-LPME and EME are compatible with different analytical in-struments for chromatography, electrophoresis, atomic spectroscopy, mass spectrometry, and electrochemical detection. HF-LPME and EME have gained significant popularity during the recent years. This review focuses on hollow fiber based techniques (especially HF-LPME and EME) of heavy metals and pharmaceuticals (published 2017 to May 2019), and their combinations with atomic spectroscopy, UV-VIS spectrophotometry, high performance liquid chromatography, gas chromatography, capillary elec-trophoresis, and voltammetry.