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Aims. To explore the relationship between gestational diabetes mellitus (GDM) and neonatal cord blood amino acid and carnitine levels after GDM was diagnosed among pregnant women monitoring glycosylated haemoglobin levels of 5.5%-6.4% during mid-late gestation. Methods. In all, 7289 qualified participants were recruited and divided into two groups (GDM and control groups) between 1 July 2015 and 1 July 2020, and all maternal-neonatal data were collected and analyzed at three centers. Results. Interestingly, glycine in cord blood was not only significantly different between groups (15.52 vs. 6.67, P < 0.001 ) but also associated with neonatal hypoglycemia ( r = 0.132 , P < 0.001 ). Although glycine was an independent positive factor with neonatal hypoglycemia, it had lacked effective size to predict the risk of neonatal hypoglycemia ( b = 0.002 , P < 0.001 ). Conclusion. The study identifies some differences and relationships in maternal-neonatal data when the GDM group has fluctuating glycosylated haemoglobin levels of 5.5%-6.4% without hypoglycemic drug intervention, compared with the control group. Although umbilical cord blood of glycine levels has a lack of effective power to predict the risk of neonatal hypoglycemia, it is probably an independent factor involved in the maternal-neonatal glucolipid metabolism.

Background To explore the relationship between maternal-neonatal clinical data and the changes of cord blood amino acid and carnitine levels between pregnant women with gestational diabetes mellitus (GDM) when glycosylated hemoglobin levels of 5.5%-6.4% excluded diabetic medicine as GDMa group and the control group. Methods In all, 312 qualified participants were recruited with permission from the ethical department of the Fifth Affiliated Hospital of Sun Yat-Sen University and divided into two groups (GDMa and non-GDM) after adjusting for maternal age and body mass index (BMI) between the 1 June 2017 and 30 April 2020. All maternal-neonatal data were collected and analysed at the centre. Results Interestingly, glycine in cord blood was not only significantly different between groups(594.19 vs 407.45, P a group, glycosylated hemoglobin levels of 5.5%-6.4% without diabetic medicine, compared with the control group which adjusted by age and BMI. Particularly, umbilical cord blood of glycine levels is related to the diabetic status of glycosylated hemoglobin 5.5%-6.4% in GDM during pregnancy and could be potential diabetic mechanism by maternal-fetal interface.

A new method of capillary electrophoresis (CE) using laser induced fluorescence (LIF) detection via online pre-concentration techniques including transient trapping combined with the dynamic pH junction mode was developed for the sensitive determination of glutathione in biological samples. The mechanism together with the important parameters governing the pre-concentration and separation were investigated in order to obtain maximum resolution and sensitivity. The analytes were compressed into a narrow zone due to the effect of the dynamic pH junction mode, and then transiently trapped by SDS micelles at the interface of the sample and micellar areas. Under the optimal conditions, the limits of detection for reduced glutathione, glycine, oxidized glutathione, cysteine, and glutamic acid were 0.01, 0.01, 0.5, 0.7, and 0.1 nM (S/N = 3), respectively. The enhancement factors obtained when using the transient trapping combined with the dynamic pH junction mode as a pre-concentration process were enhanced from 87 to 430 when compared to the results obtained by the classical capillary zone electrophoresis (CZE) mode. Moreover, this optimized method was successfully applied to bacteria (Escherichia coli, Salmonella typhimurium, and Staphylococcus aureus) and HaCaT cell samples for the determination of reduced glutathione with satisfactory recoveries.

We reported the use of polydopamine/Au nanoparticles/DNA (PDA/Au NPs/DNA) as a stationary phase for the separation of tryptophan enantiomers by microchip capillary electrophoresis (MCE). The stationary phase was formed by sequentially immobilizing PDA/Au NPs and DNA to the glass microfluidic channel surface using layer-by-layer assembly. The formation of PDA/Au NPs as a functional film involved the use of HAuCl4 as an oxidant to trigger DA self-polymerization. DA was then used as a reductant to reduce HAuCl4 to Au NPs. All these Au NPs were simultaneously deposited on the microchip surface by the adhesive PDA, and the thiolated DNA was strongly adsorbed onto the glass microfluidic channel surface through covalent gold–sulfur bonding. The functional film of the PDA/Au NPs/DNA was characterized by scanning electron microscopy, UV-vis spectra and ATR-FT-IR. The influence of separation voltage and the concentration and pH value of the running buffer were found to significantly influence separation. Successful baseline separation of tryptophan enantiomers was achieved within 65 s utilizing an effective separation length of 33 mm, and coupling with laser-induced fluorescence detection resulted in a resolution factor of 2.95. All these evaluation parameters, including stability and reproducibility, were considered satisfactory. The method outlined here, using the PDA/Au NPs/DNA-coated microfluidic channel as a versatile platform, may offer a processing strategy to prepare a functional surface on microfluidic chips.

A capillary column was prepared by continuously packing ostadecylsilane (ODS) and taurine derivatized silica (TDS) in one column without interface. This continuously packing chromatography (CPC) column is easy to operate, has good stability and shows simultaneously separation of both polar and non-polar compounds. The simultaneous separation of a series of complex samples with highly hydrophobic components (benzene, toluene, ethylbenzene, and PAHs) and highly hydrophilic components (biogenic amines, bases and nucleosides) using this CPC method was investigated. The relative parameters such as the volume fraction of acetonitrile and length of the ODS and the TDS phases were investigated and optimized. The experimental results show that this column combines the advantages of both ODS and TDS stationary phases, and exhibits a reversed phase liquid chromatography (RPLC) mode followed by a hydrophilic interaction liquid chromatography (HILIC) mode when 80% of acetonitrile was used in the mobile phase. The satisfactory results indicate that the CPC method provides an easy way to simultaneously separate polar and non-polar compounds.

Microchip electrophoresis (MCE) is particularly attractive as it provides high sensitivity and selectivity, short analysis time and low sample consumption. An on-line preconcentration strategy combining field-amplified stacking (FASS) and reversed-field stacking (RFS) was developed for efficient and sensitive analysis of neurotransmitters in real urine samples by MCE with laser induced fluorescence (LIF) detection. In this study, the multiple-preconcentration strategy greatly improves the sensitivity enhancement and surpass other conventional analytical methods for neurotransmitters detection. Under optimal conditions, the separation of three neurotransmitters (dopamine, norepinephrine and serotonin), was achieved within 3min with limits of detection (S/N=3) of 1.69, 2.35, and 2.73nM, respectively. The detection sensitivities were improved by 201-, 182-, and 292-fold enhancement, for the three neurotransmitters respectively. Other evaluation parameters such as linear correlation coefficients were considered as satisfactory. A real urine sample was analyzed with recoveries of 101.8-106.4%. The proposed FASS-RFS-MCE method was characterized in terms of precision, linearity, accuracy and successfully applied for rapid and sensitive determination of three neurotransmitters in human urine.

A simple, economical, and sensitive capillary electrophoresis (CE) method integrated with capacitively coupled contactless conductivity detection was developed for the determination of metal ions such as K+, Na+, Mg2+, Sr2+, Ca2+ in drinking water. 18-Crown-6 ether and Hexadecyltrimethylammonium Bromide (CTAB) were employed as complexing reagents. The effects of electrolyte additives, citric acid buffer solution, and other separation conditions of CE were comprehensively investigated and carefully optimized. The best results were obtained in a running buffer solution composed of citric acid (12 mM), 18-crown-6 ether (0.2 mM), and CTAB (0.015 mM) at pH 3.5. Under these conditions, a complete separation of five metal ions was successfully achieved in less than 12 min. The limits of detection for the optimal procedure were determined to be in the range of 0.02 - 0.2 mg·L-1. The repeatability with respect to migration times and peak areas, expressed as relative standard deviations, was better than 2.3% and 5.1%, respectively. Evaluation of the efficiency of the methodology indicated that it was reliable for the determination of metal ions in six different brands of drinking water samples.

A novel Congo red (CR) derivatized silica stationary phase was prepared and packed into a fused silica capillary tube for nano-flow HPLC. A variety of analytes including poly-aromatic hydrocarbons, parabens, acids, sulfonamides, bases, and nucleosides were successfully separated using the CR. In comparison with commercial ODS columns, this new stationary phase has a different separation mechanism (hydrophobically-assisted ion-exchange), which was evident in the separation of benzoic acid derivatives and sulfonamides. The successful application of CR-bonded silica stationary phase in the HILIC and PALC modes demonstrates the effectiveness of this potential chromatographic material in nano flow HPLC.

In this paper, a microchip electrophoresis method based on on-line multiple-preconcentration techniques combining field-amplified sample stacking and reversed-field stacking was developed for highly efficient analysis of acrylamide in food products. The related mechanism as well as important parameters governing separation and preconcentration have been investigated in order to obtain maximum resolution and sensitivity. The best separation was achieved using a 100mM borate solution at pH 9.3 as running buffer, and a sensitivity enhancement factor of 432 was obtained using this concentration method under optimal conditions. The detection limit of acrylamide was 1ng/mL, which was comparable to those previously obtained using CE methods with on-line preconcentration techniques and was 41-700 times lower than those previously reported CE methods without concentration process. The proposed method also gave satisfactory and reliable results in the analysis of acrylamide in potato chips and French fries.