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Objective: To explore the value of multi-slice spiral CT (MSCT) in predicting microvascular invasion in hepatocellular carcinoma (HCC). Methods: The CT and clinical data of 102 patients with HCC were collected for retrospective analysis from January 2018 to December 2020 at Baoji Center Hospital, China. They were divided into two groups based on the pathological results with or without microvascular invasion. The independent sample t-test was used to compare the age, alpha-fetoprotein (AFP) value, tumor size, and tumor enhancement of the two groups. CT value; χ2 test was used to compare gender, hepatitis type, liver function classification, degree of classification, degree of tumor smoothness, envelope, peripheral enhancement, etc. between the two groups. Results: There were 52 cases of non-microvascular invasion and 50 cases of microvascular invasion. The tumor size, grade, degree of margin, capsule, portal vein CT value, and peripheral enhancement were related to microvascular invasion. Conclusion: Microvascular invasion of HCC can be predicted by MSCT manifestations before surgery. doi: https://doi.org/10.12669/pjms.37.6-WIT.4851 How to cite this:Li K, Peng Y, Tian H, He H. Value of spiral CT multi-parameter combined preoperative evaluation of microvascular invasion in small liver cancer. Pak J Med Sci. 2021;37(6):1605-1609. doi: https://doi.org/10.12669/pjms.37.6-WIT.4851 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

The aqueous biphasic system based on choline ionic liquids and ethylene/propylene oxide copolymer coupled with high-performance liquid chromatography-tandem mass spectrometry was developed for the simultaneous determination of the enantiomers of two fungicides: myclobutanil and tebuconazole. The influence of mass fractions of ionic liquids and the copolymer on the extraction efficiency of the target fungicides was investigated. The analytes are mainly concentrated in the bottom, copolymer-rich phase. The extraction efficiencies of the selected fungicides were significantly affected by the concentrations of the copolymer, and their extraction efficiencies decreased with the higher mass fractions of the copolymer, while the mass fraction of ionic liquids had little effect on their extraction behavior. Excellent extraction efficiency was achieved using the aqueous biphasic system based on choline L-lysinate and the copolymer. At three spiked concentrations of 0.01, 0.05, and 0.1 mg/kg, the average recoveries of the selected fungicides ranged from 80 to 89%, with the relative standard deviations in the range of 2.1-5.3%. Limits of quantitation for the enantiomers of tebuconazole and myclobutanil were 0.5 and 5.0 µg/kg, respectively. The developed system could be successfully applied to the analysis of triazole fungicides residue in real samples.

A simple and environmentally friendly method was developed for simultaneous determination of residue from three triazine herbicides (simetryn, prometryn, and atrazine) from honey samples. The selected herbicides were extracted and purified using an aqueous biphasic system (ABS) based on an ethylene oxide/propylene oxide copolymer (EOPO-2500) and choline acetate ([Ch][Ac]), and determined by HPLC–MS/MS. The partitioning behavior of the analytes using the ABS was investigated, and the analytes mainly concentrated in the copolymer phase. At three spiked levels (2.0, 20.0, 100.0 μg kg−1), the recoveries of the analytes were determined in the range of 81–108%, with relative standard deviations no higher than 10.5%. The limits of quantification for the herbicides ranged from 0.1 to 1.5 µg kg−1. The proposed method is very promising for sample preparation, taking into account its simple operation, mild conditions, and biocompatibility, without the use of any organic solvents during the extraction process.

Apoptosis of tubular epithelium cells (TECs) plays critical roles in renal ischemia reperfusion (I/R) injury, but the molecular regulatory mechanisms of apoptosis still require further investigation. Recently, phosphatase family members have been suggested to regulate multiple aspects of the injury and regeneration response. However, the roles of SHP-1, an important protein-tyrosine phosphatase, in the regulation of renal I/R injury remain unknown. Here, we found that SHP-1 knockdown in vivo significantly increased renal I/R injury and aggravated the apoptosis of TECs. Consistently, after SHP-1 knockdown in TECs in vitro, a sharp increase of apoptosis induced by cobalt dichloride was found. The protective role of SHP-1 was also validated in a TEC cell line stably overexpressing SHP-1. Mechanistically, the ASK1/MKK4/JNK pro-apoptosis signal was over activated after SHP-1 knockdown, and SHP-1 could bind to and dephosphorylate ASK1 to inhibit its activation, thus repressing apoptosis.

Background Inhomogeneous magnetization transfer (ihMT) has been reported to feature superior sensitivity and specificity for myelin imaging. However, the reproducibility on ihMT has yet been rarely investigated up to date. The purpose of the present study is to assess the multi-center reproducibility and test-retest variability of ihMT in central nervous system. Methods 5 volunteers were recruited and scanned twice on three 3.0 T magnetic resonance imaging (MRI) scanners using ihMT with identical scan parameters. The maps of quantitative ihMT (qihMT) and ihMT ratio (ihMTR) for each scan were calculated. Voxel based analysis then was performed to generate qihMT and ihMTR values for major white matter fibers. The intra- and inter-scanner reliability and reproducibility was assessed with intraclass correlation coefficients (ICCs). Bland-Altman method was used to show the level of agreement between two measurement types. Paired t-test and one-way ANOVA test were also used to compare the difference between inter- and intra-scanner, respectively. Results In the 10 major white matter tracts areas, the ICCs indicated high intra- and inter-scanner measurement reliability and reproducibility. The Bland-Altman plots together with 95% confidence interval (CI) across all ROIs in the five volunteers also demonstrated good repeatability. No significant inter- and intra-scanner differences were found in Paired t-test and one-way ANOVA tests. Conclusion Good inter- and intra-scanner reliability and reproducibility of ihMT measurements were observed in this study. These findings support the use of ihMT measurements as biomarkers in multicenter and/or longitudinal studies.

Aqueous biphasic systems (ABS) composed of the choline alkanoate ionic liquids (ILs) choline acetate [Cho][OAc], choline propanoate [Cho][Pro], choline butyrate [Cho][But], and choline hexanoate [Cho][Hex], mixed with K3PO4 solutions at pH 7.2 and 14.5, were prepared and their phase diagrams were compared. The ability to form ABS with alkaline K3PO4 solutions decreased in the order [Cho][OAc] ≈ [Cho][Pro] &gt, [Cho][But] &gt, [Cho][Hex], while with neutral K3PO4 solutions, [Cho][OAc] could not form an ABS, and the other three ILs performed similarly. All of the biphasic regions of the ABS decreased with the increase in pH. 1H-NMR data indicated anion exchange between phases in ABS at neutral pH. The ABS at neutral pH were evaluated to extract the triazine herbicides simazine, cyanazine, and atrazine, and the ABS formed by [Cho][Pro] and the pH 7.2 K3PO4 solution has shown extraction recoveries higher than 90%.

Aqueous biphasic systems (ABS) based on the surfactant (triton x-100, Tr) and cholinium ionic liquids were developed for the extraction of three herbicides (simetryn, prometryn, and atrazine). The influence of the phase compositions and temperature on the formation of the ABS was investigated. The biphasic region of the ABS decreased with the longer carbon chain of the anions in ILs, while increased with the higher temperature. The partitioning behaviour of the selected herbicides using the (Tr + choline acetate [Ch][Ac] + water) ABS was studied, and the analytes mainly concentrated the surfactant-rich phase. The partition coefficients of the herbicides decreased with increasing mass fractions of Tr, while increased with the higher concentrations of [Ch][Ac], which means that salting-out ability of the IL played the important role on the system formation. The developed ABS is a promising method considering its simple operation, mild condition and biocompatibility without using any organic solvent during the extraction process.

Aqueous biphasic systems comprising ethylene/propylene oxide copolymer (EOPO-2500) and choline acetate ([Cho][OAc]) were used for extraction of three herbicides (simazine, cyanazine, and atrazine) from aqueous samples. The influence of phase composition and temperature on phase separation as measured by tie-line lengths (TLLs) and thus, on the partition coefficient (K), of the herbicides was investigated. The herbicides preferred the EOPO-rich phase. The partition coefficients decreased with higher concentrations of EOPO-2500 and [Cho][OAc] and with increasing temperatures (i.e., K decreases with higher TLLs). The proposed system was more environment-friendly and fast compared to traditional liquid–liquid extraction, considering that no organic solvent was consumed.

A rapid and simple sample preparation method was developed for simultaneous determination of three triazine herbicides in honey samples. The selected herbicides were extracted from honey samples by ionic liquid dispersive liquid–liquid microextraction, separated on a C18 column (250 mm × 4.6 mm i.d., 5 μm) using acetonitrile and H2O as the mobile phase with gradient elution, and then detected by high-performance liquid chromatography. The parameters, such as the type and volume of the extraction and disperser solvent, ion strength, pH, extraction time and centrifuge time were optimized in order to provide the excellent extraction performance. Good linearity was showed for all the target herbicides over the tested concentration range with correlation coefficient higher than 0.994. Three spiked levels (0.005, 0.05, 0.10 mg/kg) were applied for determination of the recoveries of the targets in honey samples in the range of 80–103% with relative standard deviations not larger than 10.6%. The limits of quantification for the analytes ranged between 1.5 and 4.0 μg/kg. The developed method was applied for determination of the target compounds residues in real samples. This article is protected by copyright. All rights reserved

Multiple sclerosis (MS) is a central nervous system disorder that may eventually affect its function. The clinical standard for MS severity is based on a clinical scale, which lacks lesion specific information. Magnetic resonance imaging of MS faces the challenge of myelin specificity, and in this work a new method inhomogeneous magnetization transfer (ihMT) is investigated as new biomarker of demyelination in MS.Local ethics committee approved this study and written informed consents were obtained. Between Oct 2017 to May 2018, eighteen patients with relapsing-remitting MS (RRMS) (6 males, 12 females, mean age 31.2) and sixteen healthy volunteers (6 males, 10 females, mean age 30.4 years) were enrolled in this prospective study. All subjects underwent MRI exams including MT and ihMT imaging as well as the Expanded Disability Status Scale (EDSS) assessments. Independent sample t-test were used to compare the difference of ihMT parameters between healthy white matter (HWM) and normal appearing white matter (NAWM) and between HWM and MS lesions, respectively. Spearman correlation were used to analyze the correlation between ihMT parameters of MS lesions and EDSS score.The ihMTR and qihMT demonstrate significant differences between WHM and NAWM groups, while no significant differences are observed for MTR and qMT. All parameters show significant differences between HWM and MS groups (p 0.05). There was moderate negative correlation between MTR, qMT and EDSS score (-0.440 and -0.572), while there was a strong negative correlation between ihMTR and qihMT and EDSS score (-0.704 and -0.739).Based on whole brain analysis at 3.0 T, ihMT showed better correlation with EDSS compared to magnetization transfer imaging, and may be a potentially valuable biomarker for demyelination in MS.

Aqueous biphasic systems comprising ethylene/propylene oxide copolymer (EOPO-2500) and choline acetate ([Cho][OAc]) were used for extraction of three herbicides (simazine, cyanazine, and atrazine) from aqueous samples. The influence of phase composition and temperature on phase separation as measured by tie-line lengths (TLLs) and thus, on the partition coefficient (K), of the herbicides was investigated. The herbicides preferred the EOPO-rich phase. The partition coefficients decreased with higher concentrations of EOPO-2500 and [Cho][OAc] and with increasing temperatures (i.e., K decreases with higher TLLs). The proposed system was more environment-friendly and fast compared to traditional liquid–liquid extraction, considering that no organic solvent was consumed.

Helix B surface peptide (HBSP) is an erythropoietin (EPO)-derived peptide that protects tissue from the risks of elevated blood pressure and thrombosis. This study focused on the protection of HBSP in hepatic ischaemia/reperfusion (I/R) by enhancing the level of autophagy. In detail, we randomly divided C57BL/6 mice into sham-operated, hepatic ischaemia/reperfusion (I/R), I/R + HBSP, I/R + HBSP + 3-methyladenine (autophagy inhibitor), I/R + HBSP + rapamycin (mTOR inhibitor), and I/R + HBSP + Ly294002 (Akt inhibitor) groups. We assessed alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) levels in mouse sera, and performed haematoxylin/eosin (HE) staining, immunohistochemistry, electron microscopy, immunofluorescence microscopy, and western blotting on liver tissue to detect the degree of liver injury, liver apoptosis, autophagy, and the expression of microtubule associated protein 1 light chain 3 alpha (Map1lc3, or LC3), Beclin 1, phospho-mTOR, mTOR, phospho-Akt (P-Akt), and Akt. HBSP relieved hepatic I/R injury in a concentration-independent manner. The expression of LC3II, LC3I, and Beclin 1, and the formation of autophagosomes, in the I/R + HBSP group were higher than those in the I/R group. The protective effects of HBSP were abolished by 3-methyladenine and, to a lesser extent, Ly294002, but enhanced by rapamycin. Furthermore, In vivo, HBSP also protected against hypoxia injury induced by cobalt chloride (CoCl2) through improving the level of autophagy. Therefore, HBSP protected against hepatic I/R injury, mainly via regulating autophagy by targeting mTOR.

Aqueous biphasic systems (ABS) have attracted considerable attention for their unique applications in extraction and purification processes. Choline-based ionic liquids (IL), deep eutectic solvents (DES), or buffers have been studied as replacements to traditional organic solvents because they can be designed to be non-flammable, non-volatile, of low toxicity, and biocompatible. ABS based on the use of choline IL/DES/buffers, thus offer potentially extensive benefits in extraction and separation technology. In this review, the development of choline-based ABS and their application to the extraction and purification of small organic molecules, proteins, and DNA are discussed and the different types of ABS compared and evaluated. The advantages, drawbacks, and further work needed to bring this technology to fruition are also presented.

Figure S1. The Effect of PCM on T Cells and Jurkat cells, Related to Fig. 1. Figure S2. ROS Scavenger and Inhibitor of CIII Could Weaken the Effect of PCM on T cells. Figure S3. ROS Scavenger and Inhibitor of CIII Could Weaken the Effect of PCM on T cells. Figure S4. The Media of RM-1 Have No Effect on SHP1 Knockdown T Cells. Figure S5. Quality Control of the RNAseq, Rlated to Fig. 3. Figure S6. Quality Control of the Metabonomics, Rlated to Fig. 5. Figure S7. The Efficiency of PRODH Knockdown and the Effect to Cell Number, and the Effect of Additional P5C on Human CD3+ T Cells, Related to Fig. 6. Figure S8. The Change of PRODH Expression Affect CD4+ and CD8+ T cells Infiltration in vivo Which Have no Influence on Nude Mice Xenograft. Table S1. The clinical information on the patients. (DOCX 3226 kb)

A sensitive method for determination of chloramphenicol, enrofloxacin and 29 pesticides residues in bovine milk by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed. Residues of the targets were extracted from milk with acetonitrile, cleaned up by C(18)-SPE cartridge, and then determined by HPLC-MS/MS. The MS detection was operated in positive or negative ionization mode, depending on the compounds. For confirmation of each target compound, two precursor ion>product ion transitions were selected by multi-reaction monitoring mode (MRM). The method showed good linearity for all the tested compounds over the studied concentration range with correlation coefficient higher than 0.9910. Recoveries for the studied compounds at three spiked levels (0.05, 0.10, 0.19mgkg(-1)) in bovine milk were in the range of 71-107% with RSDs not larger than 13.7%, except that recoveries of trifluralin ranged between 62% and 70% at the spiked levels. Limits of quantitation for the analytes were estimated to range between 0.03×10(-3) and 14.5×10(-3)mgkg(-1). The proposed method was applied for the determination of the analytes residues in real samples. The found levels of the analytes in milk samples were lower than maximum residues levels (MRL).

A method for determination of chlormequat (CCC) residue in fruits by liquid chromatography–tandem mass spectrometry (LC–MS–MS) was developed. Residue of CCC was extracted from samples with methanol–water (v/v, 1:1) containing 1.0% acetic acid, cleaned up by strong cationic exchange (SCX) cartridge, and then determined by LC–MS–MS. The method showed good linearity over the concentration range 0.002–5.0 mg kg−1 with correlation coefficient above 0.997. The limit of detection (LOD) and limit of quantitation (LOQ) for CCC were 5 × 10−4 mg kg−1 (S/N = 3) and 0.002 mg kg−1 (S/N = 10), respectively. Recoveries for CCC at three spiked levels (0.025, 0.050, and 0.20 mg kg−1) were in the range 80–102%. Estimation of measurement uncertainty was calculated for CCC at the level of 0.025 mg kg−1 in fruits. The results demonstrated that the uncertainty of recovery was the main contribution to the combined standard uncertainty. The relative combined standard uncertainties associated with the method ranged from 11 to 13%, depending on the sample matrices.

To overcome the peak band broadening and to increase the peak capacity and separation efficiency of a two-dimensional liquid chromatographic system, a high-temperature normal phase liquid chromatography (HTNPLC) was used as the first dimension (1st-D), and a RPLC was used as the second dimension (2nd-D). The sample was first separated on the 1st-D CN column and the primary eluent stored in the sampling-loop system alternatively (in HTNPLC×RPLC mode) or selectively (in HTNPLC/RPLC mode) and was then transferred to 2nd-D C18 column for further separation. The resolution and separation efficiency of the systems were greatly improved. The systems were evaluated by analyzing several polycyclic aromatic hydrocarbons and Glycyrrhiza uralensis extract.

A comprehensive two-dimensional liquid chromatographic system was developed using a vacuum-evaporation interface (VEI). A normal-phase liquid chromatography (NPLC) with a CN microcolumn was used as the first dimension (1st-D), and a reversed-phase liquid chromatography (RPLC) with a C18 monolithic column was used as the second dimension (2nd-D). A two-position, ten-port valve with two identical storage loops was used as the interface that enabled alternate sampling of the first column eluent onto the second column until the analysis was finished. In one of the two positions, the eluent from the first column filled one of the loops and was evaporated at 25 °C under vacuum leaving the analyses to stick onto the inner wall of the loop. When the valve was switched to the second position, the effluent from the first column flowed through the other loop, whereas mobile phase of the 2nd-D dissolved the analyses in the loop from the previous cycle and injected them onto the second column allowing online solvent exchange of the fractions from the 1st-D to the 2nd-D. The utility of the comprehensive 2D-LC system was demonstrated in the analysis of standard samples and traditional Chinese medicine Cnidium monnieri (L.) Cuss extract.

A comprehensive two-dimensional liquid chromatographic system incorporating a vacuum-evaporation interface was developed. Normal-phase liquid chromatography with a CN microcolumn was used as the first dimension (1(st)-D), and reversed-phase liquid chromatography with a C(18) monolithic column was used as the second dimension (2(nd)-D). An electronically controlled dual-position, ten-port valve with two identical storage loops served as the interface and the analysis time in the 2(nd)-D was 1.5 min. The solvent in the loops of the interface was evaporated at 25 degrees C under vacuum conditions, leaving the analytes on the inner wall of the loops. The mobile phase of the 2(nd)-D dissolved the analytes in the loop and injected them onto the second column, allowing an on-line solvent exchange of the fractions from the 1(st)-D to the 2(nd)-D. The chromatographic resolution of analytes on the two dimensions was evaluated. Sample loss due to evaporation in the interface was investigated with standard samples having different boiling points. The usefulness of the comprehensive 2-DLC system was demonstrated in the analysis of a traditional Chinese medicine Radix salviae miltiorrhiza bage extract.

the effect of axial temperature gradient (atg) along a microcolumn on the separation performance at both isocratic and gradient elution mode was investigated. a thermostat system was designed to form an atg along the packed column. polycyclic aromatic hydrocarbons (pahs) were separated on a 0.53 mm x 150 mm i.d. 5 mu m c-18 microcolumn, with water and acetonitrile as mobile phase. the separation results obtained at mobile phase gradient (mpg) and atg in microcolumn hplc were compared with the results performed at ambient conditions. extrapolated curves of peak width at half height (w(h)) versus ink showed that w(h) is narrower at the same retention time when atg was applied in addition to mpg. the column efficiency was enhanced 20-30% and the resolution was slightly reduced because of reduction of selectivity at elevated temperature at atg condition. the rsd of retention time in atg mode was less than 2.5%. (c) 2006 elsevier b.v. all rights reserved.

A simple on-line preconcentration method of protein for capillary electrophoresis (CE) using a cellulose acetate (CA)-coated porous membrane was proposed. CA membrane is fabricated at one of the ends of the column that allows the passage of buffer ions but excludes larger protein molecules. Protein sample is continuously electrokinetically loaded and trapped by the membrane. When injection is completed, the direction of the electric field is switched and the trapped proteins are then separated by conventional CE procedure. The results achieved showed that the preconcentration mechanism of this method was based on size-exclusion effect. Bovine serum albumin (BSA) was used for model protein sample, and signal enhancement of 550-fold with 15 min injection time was achieved.

A packed microcolumn solid-phase extraction coupled online to a capillary liquid chromatography (CapLC) was described and evaluated. A short packed capillary column (65 mm×0.45 mm i.d., 5 μm C 18 ) was used as the extraction cartridge and was mounted on a 10-port switching valve. A given volume of sample in a sample loop mounted on an injection valve passed through the cartridge, which retained the target compounds of the sample. The compounds were then desorbed by mobile phase, and were separated on an analytical column. Anisaldehyde water sample was used as the standard sample to evaluate the system. The calibration curve was linear (r > 0.998) over the concentration range of 0.01–0.5 mg l −1 . The relative standard deviations of the retention time, the peak height, and the peak area of anisaldehyde in the linear ranges were 1.4%–2.2%, 4.2%–5.7%, and 6.0%–10.1%, respectively. The detection limit of anisaldehyde using this device was 6.0×10 −3 μg/L (S/N=3). In addition, the sensitivity of some apolar aromatic hydrocarbon compounds could be improved by 30–100 folds. The method was applied for the determination of traces of naphthalene in seawater, with a detection limit of 0.13 μg l −1 (S/N=3).

DNA methylation can control gene expression and may also play a role in plant development. Methylation of cytosine residues in DNA is enzymatically catalyzed by DNA methyltransferases. In this study, full-length genomic genes and cDNAs of methyltransferase (MET1) and domain-rearranged methyltransferase (DRM) were isolated from strawberry (Fragaria × ananassa Duch.). Two genomic clones (FaMET1a and FaMET1b) encoding MET1 had open-reading frame of 4,695 and 4,671 nucleotides with two introns, respectively. Amino acid sequence comparison indicated high similarity (98.72% identity) of strawberry MET1 protein to other plant MET1 sequences. The full-length cDNA of strawberry DRM genes (FaDRMa, FaDRMb and FaDRMc) were 2,273, 2,282 and 2,288 bp, respectively. Ten introns with different sizes were dispersed in FaDRM genes. Similarly, FaDRMa, FaDRMb and FaDRMc had high-sequence similarity overall. Expressions of strawberry MET1 and DRM genes were compared among in vitro-micropropagated plants, generations of micropropagated plants and conventionally propagated plants. The transcriptional expressions of both FaMET1 and FaDRM genes were downregulated in micropropagated plants, and they were recovered in the first and second runner generations of micropropagated plants. However, there was a slighter difference in global DNA methylation rates between micropropagated plants and conventionally propagated plants. Therefore, there was no positive relation between global DNA methylation rates and the expression levels of MET1 and DRM genes.

An orthogonal two-dimensional liquid chromatographic (2D-LC) system was developed by using a vacuum-evaporation loop-type valve interface. Normal-phase liquid chromatography (NPLC) with a bonded CN phase column was used as the first dimension, and reversed-phase liquid chromatography (RPLC) with a C(18) column was used as the second dimension. All the solvents in the loop of the interface were evaporated at 90 degrees C under vacuum conditions, leaving the analytes on the inner wall of the loop. The mobile phase of the second dimension dissolved the analytes in the loop and injected them onto the secondary column, allowing an on-line solvent exchange of a selected fraction from the first dimension to the second dimension. The chromatographic resolution of analytes on the two dimensions was maintained at their optimal condition. Sample loss due to evaporation in the interface was observed that depended on the boiling point of the compound. Separation of sixteen polycyclic aromatic hydrocarbon mixtures and a traditional Chinese medicine Angelica dahurica was demonstrated.

Isoflavonoids in Pueraria lobata extract and its preparations were separated and identified by reversed-phase capillary liquid chromatography (RP-CapLC) coupled with photodiode array (PDA) detector and negative electrospray ionization quadrupole time of flight (Q-TOF) mass spectrometry. The separation was performed on a 150 mm x 0. 32 mm i. d. , 5 microm C18 capillary column, using mobile phase of 0.1% aqueous trifluoroacetic acid solution and acetonitrile containing 0.1% trifluoroacetic acid under gradient elution. The product ion spectra of the deprotonated ions allowed for the identification of puerarin, daidzin and daidzein in the sample. Puerarin was found to be the most abundant component in the extract (about 13%, mass fraction) and its preparations (19.28 - 24.34 mg per tablet). The structures of trace amount of unknown isoflavonoids were deduced based on the spectra of known compounds. They were proposed to be 3'-methoxypuerarin and 3'-methoxydaidzin.

A miniaturized fluorescence detector utilizing a three-dimensional windowless flow cell has been constructed and evaluated. The inlet and outlet liquid channels are collinear and are located in the same plane as the excitation paths, while the optical fiber used to collect the emission light is perpendicular to this plane. The straightforward arrangement of the flow path minimizes band dispersion and eliminates bubble formation or accumulation inside the cell. The use of high-brightness light-emitting diodes (LEDs) as the excitation source and a miniaturized metal package photomultiplier tube (PMT) results in a compact and sensitive fluorescence detector. The detection limit obtained from the system for fluorescein isothiocyanate (FITC) in flow injection mode is 2.6 nmol/L. The analysis of riboflavin and FITC by packed capillary liquid chromatography is demonstrated.

An integrated light emitting diode (LED)-induced fluorescence detector was described and evaluated. The LED and its related components including lens and interference filter, the optical fiber used to collect fluorescence, and the capillary column are integrated into a substrate block, which eliminates the need of align procedure of the fiber and the capillary. Forty-fold enhancement of sensitivity was obtained compared with our previous work and the detection limit for fluorescein was 5nM. Application of the detector for the analysis of FITC-labeled Ephedrine extract was demonstrated.