Objective:To establish an accurate, stable, and convenient Taka amylase enzymolysis ion-selective electrode method for determination of trace fluoride in Mongolian milk tea powder.Methods:The samples of instant Mongolian milk tea powder were heated and dried at 50 ℃, 1.0 g of the sample was accurately weighed and dissolved in pure water. The sample solution, Taka amylase, and total ion strength buffer solution were mixed and enzymatically hydrolyzed in a 55 ℃ water bath for 60 minutes. After cooling, filtration was carried out. The clarified liquid was collected and the fluoride content was detected by the ion-selective electrode method, and the method validation test was conducted.Results:When the standard linear concentration range was 0.2 to 5.0 mg/L, the correlation coefficient ranged from 0.999 5 to 0.999 9. The detection limit of the method was 0.006 mg/kg. The relative standard deviations ( RSD) for detecting high, medium, and low concentration samples were 0.8%, 1.9%, and 2.1%, respectively. The recovery rates ranged from 98% to 101%, 95% to 101%, and 101% to 107%, respectively. This method simultaneously measured the same batch of samples with the second method of the "National Food Safety Standard - Determination of Fluorine in Foods" (GB 5009.18-2025) - the ion-selective electrode method. The results were (23.1 ± 7.7) and (22.5 ± 7.6) mg/kg, respectively. There was no statistically significant difference between the two methods ( t = 2.01, P = 0.066). Conclusion:The Taka amylase enzymolysis ion-selective electrode method has good reproducibility and high accuracy, making it suitable for determination of trace fluoride in Mongolian milk tea powder.

Objective:To establish an accurate, stable, and convenient Taka amylase enzymolysis ion-selective electrode method for determination of trace fluoride in Mongolian milk tea powder.Methods:The samples of instant Mongolian milk tea powder were heated and dried at 50 ℃, 1.0 g of the sample was accurately weighed and dissolved in pure water. The sample solution, Taka amylase, and total ion strength buffer solution were mixed and enzymatically hydrolyzed in a 55 ℃ water bath for 60 minutes. After cooling, filtration was carried out. The clarified liquid was collected and the fluoride content was detected by the ion-selective electrode method, and the method validation test was conducted.Results:When the standard linear concentration range was 0.2 to 5.0 mg/L, the correlation coefficient ranged from 0.999 5 to 0.999 9. The detection limit of the method was 0.006 mg/kg. The relative standard deviations ( RSD) for detecting high, medium, and low concentration samples were 0.8%, 1.9%, and 2.1%, respectively. The recovery rates ranged from 98% to 101%, 95% to 101%, and 101% to 107%, respectively. This method simultaneously measured the same batch of samples with the second method of the "National Food Safety Standard - Determination of Fluorine in Foods" (GB 5009.18-2025) - the ion-selective electrode method. The results were (23.1 ± 7.7) and (22.5 ± 7.6) mg/kg, respectively. There was no statistically significant difference between the two methods ( t = 2.01, P = 0.066). Conclusion:The Taka amylase enzymolysis ion-selective electrode method has good reproducibility and high accuracy, making it suitable for determination of trace fluoride in Mongolian milk tea powder.

Objective:To develop a perinatal depression screening scale for Chinese urban version and test its reliability and validity.Methods:Naturally conceived women who were≥12 weeks of gestation and had regular prenatal examinations or delivered within four weeks in Xi'an and Foshan were recruited using convenience sampling. Initial entries were created through clinical interviews and expert validation of 50 of these pregnancies. Further item screening and testing for reliability and validity using correlation analysis, critical ratio method, homogeneity test, and factor analysis were performed. The final questionnaire was formed and then used to test the subjects. Fifty women who had completed the questionnaire effectively were selected for retesting 10 to 15 days after the initial evaluation. A structural equation model was constructed using the Edinburgh Postpartum Depression Scale (EPDS) as the reference criterion to conduct the scale's exploratory and confirmatory factor analysis. The receiver operating characters curve was used to determine the cut-off point of the scale.Results:(1) 1 300 questionnaires were issued, and 1 049 valid questionnaires were received with a recovery rate of 80.7%. Among them, 601 were used for exploratory and correlation analysis, and 448 were used for confirmatory factor analysis. (2) The initial entries of the scale totaled 63. After eliminating indicators that did not meet the requirements for item analysis, the final scale consisted of 22 entries in total. The final scale consisted of six dimensions, including "abnormal mood", "loss of interest and pleasure," "sleep disorder," "self-blame and guilt," "decline in conscious thought ability," and "lack of energy". (3) The correlation coefficients between the above six dimensions and EPDS were 0.609, 0.322, 0.423, 0.522, 0.545, and 0.516, respectively. The one between the total scale and EPDS was 0.715 (all P<0.01). (4) The confirmatory factor analysis of each model and the scale showed an acceptable fit and a stable factor structure with indices Chi-square/degrees of freedom =2.504, square root of approximation error=0.058, standardized root mean square residual=0.048, comparative fit index=0.925, Tueker-Lewis index=0.911. After retaining 22 items, the Cronbach's coefficients of the six dimensions ranged from 0.708 to 0.870. (5) The test-retest reliability of the total scale, six dimensions, and 22 items were 0.936, 0.786-0.846, and 0.720-0.886, respectively. (6) The receiver operating characteristic curve of the scale was drawn with EPDS≥13 as the cut-off value, and the area under the curve (AUC) of EPDS was 0.808 (95% CI: 0.744-0.872). When the original cut-off point was 21, the Youden index was the max (0.561), with sensitivity and specificity of 0.952 and 0.609, respectively. The Kappa value was 0.691, indicating that the scale was consistent with EPDS. Conclusion:This study preliminarily established a Chinese urban version of the perinatal depression screening scale with a stable factor structure and good reliability and validity.

Objective:To develop a perinatal depression screening scale for Chinese urban version and test its reliability and validity.Methods:Naturally conceived women who were≥12 weeks of gestation and had regular prenatal examinations or delivered within four weeks in Xi'an and Foshan were recruited using convenience sampling. Initial entries were created through clinical interviews and expert validation of 50 of these pregnancies. Further item screening and testing for reliability and validity using correlation analysis, critical ratio method, homogeneity test, and factor analysis were performed. The final questionnaire was formed and then used to test the subjects. Fifty women who had completed the questionnaire effectively were selected for retesting 10 to 15 days after the initial evaluation. A structural equation model was constructed using the Edinburgh Postpartum Depression Scale (EPDS) as the reference criterion to conduct the scale's exploratory and confirmatory factor analysis. The receiver operating characters curve was used to determine the cut-off point of the scale.Results:(1) 1 300 questionnaires were issued, and 1 049 valid questionnaires were received with a recovery rate of 80.7%. Among them, 601 were used for exploratory and correlation analysis, and 448 were used for confirmatory factor analysis. (2) The initial entries of the scale totaled 63. After eliminating indicators that did not meet the requirements for item analysis, the final scale consisted of 22 entries in total. The final scale consisted of six dimensions, including "abnormal mood", "loss of interest and pleasure," "sleep disorder," "self-blame and guilt," "decline in conscious thought ability," and "lack of energy". (3) The correlation coefficients between the above six dimensions and EPDS were 0.609, 0.322, 0.423, 0.522, 0.545, and 0.516, respectively. The one between the total scale and EPDS was 0.715 (all P<0.01). (4) The confirmatory factor analysis of each model and the scale showed an acceptable fit and a stable factor structure with indices Chi-square/degrees of freedom =2.504, square root of approximation error=0.058, standardized root mean square residual=0.048, comparative fit index=0.925, Tueker-Lewis index=0.911. After retaining 22 items, the Cronbach's coefficients of the six dimensions ranged from 0.708 to 0.870. (5) The test-retest reliability of the total scale, six dimensions, and 22 items were 0.936, 0.786-0.846, and 0.720-0.886, respectively. (6) The receiver operating characteristic curve of the scale was drawn with EPDS≥13 as the cut-off value, and the area under the curve (AUC) of EPDS was 0.808 (95% CI: 0.744-0.872). When the original cut-off point was 21, the Youden index was the max (0.561), with sensitivity and specificity of 0.952 and 0.609, respectively. The Kappa value was 0.691, indicating that the scale was consistent with EPDS. Conclusion:This study preliminarily established a Chinese urban version of the perinatal depression screening scale with a stable factor structure and good reliability and validity.

Objective To establish a method for determination of 22 pesticide residues in vegetables by QuEChERS - gas chromatography-mass spectromerty. Methods The vegetables were extracted by acetonitrile, and purified by QuEChERS after being centrifuged. The sample solution was dried by nitrogen gas. The residues were then dissolved in cyclohexane /acetone (7:3) and analyzed by gas chromatography-mass spectrometry with HP-5MS and scanned by select ion scanning mode（SIM）for quantification. Results The separation of the 22 pesticide residues was good, and the linear correlation coefficients were all greater than 0.996. The detection limits were 0.001 mg/kg-0.003 mg/kg. The average recovery rate was in the range of 86.00% to 102.00% with relative standard derivations of 2.10% to 4.30%. Conclusion QuEChERS - gas chromatography-mass spectromerty is a simple, fast, sensitive, and accurate method, which is suitable for the detection of various pesticide residues in vegetables.