Objective To establish an analytical method for the simultaneous determination of 18 perfluoroalkyl compounds(PFCs)in tea leaves using a quick,easy,cheap,effective,rugged,and safe(QuEChERS)method for sample pretreatment combined with ultra-performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS).Methods The target analytes—18 PFCs—included 13 carboxylic acid PFCs(perfluorobutanoic acid[PFBA],perfluoropentanoic acid[PFPeA],perfluorohexanoic acid[PFHxA],perfluoroheptanoic acid[PFHpA],perfluorooctanoic acid[PFOA],perfluorononanoic acid[PFNA],perfluorodecanoic acid[PFDA],perfluoroundecanoic acid[PFUdA],perfluorododecanoic acid[PFTrDA],perfluorotridecanoic acid[PFTeDA],perfluorotetradecanoic acid[PFHxDA],perfluorohexadecanoic acid[PFHpS],and perfluorooctadecanoic acid[PFODA])and 5 sulfonic acid PFCs(perfluorobutanesulfonic acid[PFBS],perfluorohexanesulfonic acid[PFHxS],perfluoroheptanesulfonic acid[PFHpS],perfluorooctanesulfonic acid[PFOS],and perfluorodecanesulfonic acid[PFDS]).The QuEChERS pretreatment parameters were systematically optimized using the response surface methodology.The tea leave samples were extracted with an 80%acetonitrile solution and subsequently purified by adding a mixed absorbent consisting of 20 mg N-propyl-ethylenediamine(PSA),210 mg graphitized carbon black GCB),and 60 mg octadecylsilane(C18).The supernatant was concentrated by nitrogen blowing and subsequently re-dissolved in 50%methanol-2 mmol/L ammonium acetate solution.The re-dissolved solution was injected into the UHPLC-MS/MS for analysis.The target analytes were separated on an ACQUITY UPLC BEH C18 column(2.1 mm×50 mm,1.7 μm).The mobile phases consisted of methanol(phase A)and 2 mmol/L aqueous ammonium acetate(phase B),with a gradient elution procedure.The total running time was 18 min.The mass spectrometry analysis was conducted using an electrospray ionization source in negative ionization mode and multi-reaction monitoring(MRM),with quantification performed using the internal standard curve method.The greenness of the analytical method was assessed using Analytical GREEnness calculator(AGREE)and the Analytical Eco-Scale method(AES).Results Under the optimized conditions,the limits of detection(LODs)and limits of quantification(LOQs)of the method were 0.005 7-1.23 ng/g and 0.019-4.09 ng/g,respectively.The average recoveries of most target compounds were 71.1%-117.9%,with relative standard deviations(RSDs)below 15%.The AGREE index of the method was 0.49,and the AES score was 76.At least one PFC was detected in each of the 132 tea leave samples,and the detection rate of carboxylic acid PFC was higher than that of sulfonic acid PFC.The highest detection rates were observed for PFBA at 97.74%,PFHpA at 93.23%,and PFOA at 92.24%.In contrast,PFHpS,PFUdA,PFDoA,PFHxDA,and PFODA were not detected in the samples.Conclusion The proposed method has the advantages of simplicity,rapidity and sensitivity,and is suitable for the analysis of PFCs in tea leaves.The method has high greenness with minimal impact on the operator and the environment.The widespread presence of PFC contamination in tea leaves available in the market warrants strengthened monitoring and regulatory control.

Objective: To explore the correlation between moxibustion sensation and distance of moxa stick and provide reference for clinical practice. Methods: A total of 16 healthy volunteers aged 18-35 years old in college were recruited and given mild moxibustion at Shousanli (LI 10), Zusanli (ST 36), Shenshu (BL 23) and Tianshu (ST 25) with moxa stick, and the occurrence and frequency of moxibustion sensation were recorded at distances of 5 cm, 4 cm, 3 cm and 2 cm. Mild moxibustion scale was used to count the score. Results: Warm was the main moxibustion sensation, burning pain and soreness decreased with the rise of distance; for the same acupoint, score of mild moxibustion scale increased with the decrease of distance; score ranged between 5.5 and 6.5 at distance 3 cm, which was the most comfortable distance for volunteers. Conclusion: The distance of 3 cm is the most comfortable distance in mild moxibustion.

Objective: To explore the beneficial regulatory effect of mild moxibustion from different distances at Zusanli (ST 36) of healthy population on the functions of temperature-related brain regions. Methods: In 20 recruited healthy subjects, the change of the temperature-related brain regions induced by mild moxibustion from different distances at Zusanli (ST 36) was observed by functional magnetic resonance imaging (fMRI). Results: In comparison of the values in amplitude of low-frequency fluctuation (fALFF) during and before moxibustion, it has been found that in moxibustion of 2 cm distance, fALFF value increased in the brain regions of the left anterior cingulated cortex and lateral surrounding cerebral regions, and fALFF value decreased in the cerebral regions of the peripheral cortex of the calcarine fissure; in moxibustion of 3 cm distance, fALFF value increased in the brain regions of the right and medial side and paracingulated gyrus, and fALFF value decreased in the cerebral zone of the left middle temporal gyrus; in moxibustion of 4 cm distance, fALFF value increased in the brain regions of the right and medial and paracingulated gyrus; and in moxibustion of 5 cm distance, fALFF value increased in the brain regions of the left hippocampus. In comparison of the value of regional homogeneity (ReHo), it has been found that in moxibustion of 2 cm distance, ReHo value increased in the cerebral zone of the posterior lobe of the right cerebellum, and ReHo value decreased in the cerebral zone of the right occipital lobe; in moxibustion of 3 cm distance, ReHo value increased in the brain regions of the left cerebellar posterior lobe and left frontal lobe, and ReHo value decreased in the cerebral zone of the right inferior temporal gyrus; in moxibustion of 4 cm distance, ReHo value increased in the brain regions of the right superior frontal gyrus and ReHo value decreased in the brain regions of the right parietal lobe and angular gyrus; in moxibustion of 5 cm distance, ReHo value increased in the cerebral zone of the right frontal lobe and ReHo value decreased in the cerebral zone of the right brainstem. Conclusion: In moxibustion of 3 cm distance, the changes in the brain regions basically conform to the transmission route of body trunk temperature.