ObjectiveTo establish an High Performance Liquid Chromatography-Inductively Coupled Plasma-Mass Spectrometry （HPLC-ICP-MS） method for determination of six arsenic species in human urine，including arseniccholine （AsC）， arsenobetaine （AsB）， arsenite （As³⁺）， dimethylarsinic acid （DMA⁵⁺）， monomethylarsonic acid （MMA⁵⁺）， and arsenate （As⁵⁺）. MethodsThe pH value of mobile phase and the content of anhydrous ethanol were optimized. Ammonium carbonate （50 mmol·L^-1， containing 2% anhydrous ethanol， pH-8.5） mobile phase was selected. Cl^- interference was eliminated by He mode. The arsenic species in 10-fold diluted human urine samples were separated by an Hamilton PRP X-100 anionic column. A method for the determination of six arsenic species was established. ResultsSix arsenic species could be separated in 13 minutes. The linear correlation coefficients were above 0.999. The limits of detection were 0.10‒0.20 μg·L^-1， and the limits of quantification were 0.30‒0.50 μg·L^-1. Precision experiments showed that RSD ranged from 5.96% to 9.07% when adding concentration 0.20 μg·L^-1； from 2.48% to 6.38% when adding concentration 2.00 μg·L^-1； and from 1.41% to 2.57% when adding concentration 5.00 μg·L^-1. Accuracy test showed that the recoveries were 80%‒125%. ConclusionThe established HPLC-ICP-MS method for determination of six arsenic species in human urine is rapid， accurate and sensitive. It can be applied to the determination of arsenic species in human urine.

Objective:To evaluate the efficacy of cerebral-placental-uterine ratio(CPUR)in predicting late-on-set fetal growth restriction(FGR).Methods:From May 2020 to May 2021,1255 women with singleton pregnancy who underwent prenatal examinations at the University of Hong Kong Shenzhen Hospital were selected for fetal growth and Doppler measurements at 35-37 +6 weeks of gestation.Pregnant women with birth weight of newbo-rns＜the 10th percentile were the FGR group.The pulsatility index(PI)of uterine artery(UtA),umbilical artery(UA)and fetal middle cerebral artery(MCA)were analyzed separately and in combination.ROC curve was used to analyze the cerebral-placental-uterine ratio(CPUR),cerebral-placental ratio(CPR),cerebral-uterine ratio(C-UtA)for predicting late-onset FGR;and to evaluate the sensitivity,positive and negative predictive value and of CPUR in the prediction of late-onset FGR.Results:The area under the curve(AUC)of CPUR,CPR,C-UtA and mean UtA-PI for FGR grope were 0.88,0.86,0.84 and 0.72.Under certain cut-off values and 87% specificity,the specificity of CPUR,CPR,C-UtA and mean UtA-Pifor predicting FGR group was 43.2%,46.6%,39.8% and 23.9%,respectively.The positive predictive values of CPUR,CPR,C-UtA and mean UtA-PI,UA-PI for predicting FGR group were 90.5%,71.9%,83.3%,63.6%and 5.2%,respectively.Conclusions:CPUR is more effective in predicting late onset FGR than CPR,C-UtA and mean UtA-PI.It can effectively increase the detection rate of fetal growth restrictionand reduce the FGR risk.

Background The production and consumption of high polar pesticides in China are the largest in the world. Therefore, it is urgent to develop a method with fast analysis, large flux, and high accuracy to determine the residues of these pesticides in food. Objective To establish a method for the determination of eight highly polar pesticides [chlormequat, paraquat, difenzoquat, cyromazine, propamocarb, glyphosate, (aminomethyl)-phosphonic acid, and glufosinate] in vegetables and fruits by ultra-performance liquid chromatography-tandem mass spectrometry. Methods After comparing various types of hydrophilic interaction liquid chromatography (HILIC) columns, and optimizing pH value and buffer concentration of mobile phase, effective chromatographic retention and separation of selected eight pesticides were achieved. Based on the optimization of mass spectrometry under chromatographic conditions, a multiple reaction monitoring (MRM) channel of target compounds was established. In the sample pretreatment, through optimization of water content, extraction solvent, and purification method, a final MRM mode of ultra-performance liquid chromatography-tandem mass spectrometry was used for detection, and the isotope internal standard method was used for quantification. The accuracy and the precision of the method were evaluated using recovery and relative standard deviation. The established method was applied to detect 57 samples of retail vegetables and fruits to investigate the adaptability of the proposed method and the residual levels of selected high polar pesticides. Results For positive ion electrospray ionization (ESI⁺) detection, we chose Sielc Obelisc R as chromatographic column, and 20 mmol·L⁻¹ ammonium formate solution (pH=3±0.05) and acetonitrile as mobile phase; for negative ion electrospray ionization (ESI⁻) detection, we chose Shodex Asahipak NH2P-50 2D as chromatographic column, and 5 mmol·L⁻¹ ammonium acetate solution (pH=11±0.05) and acetonitrile as mobile phase to obtain good chromatographic separation and peak shape. Under the optimal conditions of sample water content standardization, using 2% acidified methanol as extraction solvent, and C18 dispersed solid phase extraction purification, the linearity ranges of five analytes (chlormequat, paraquat, difenzoquat, cyromazine, and propamocarb) and three analytes [glyphosate, (aminomethyl)phosphonic acid, and glufosinate] were 1.00-100 μg·L⁻¹ and 5.00-500 μg·L⁻¹ (both correlation coefficients>0.999) respectively, the detection limits were 0.002-0.010 mg·kg⁻¹, and the limits of quantification (LOQ) were 0.005-0.025 mg·kg⁻¹. At three spiked levels (LOQ, 2LOQ, and 5LOQ), the recoveries were in the range of 85.3%–113.2%, and the relative standard deviations were 1.5%–9.5% (n=6). Three target pesticides (chlormequat, cyromazine, and propamocarb) were detected in 57 samples of retail vegetables and fruits, and the residue of chlormequat in cowpea exceeded the maximum residue limit. Conclusion The established method of HILIC combined with ultra-performance liquid chromatography-tandem mass spectrometry and isotopic internal standard quantification has the characteristics of simplicity, stability, and easy operation, which is suitable for rapid screening and quantitative detection of selected eight high polar pesticide residues in large quantities of vegetables and fruits, and provides technical support for monitoring and risk assessment of high polar pesticide residues.