[Determination of lipophilic marine biotoxins in shellfish foods by ultra performance liquid chromatography-hybrid triple quadrupole linear ion trap-mass spectrometry].

OBJECTIVE: An ultra performance liquid chromatography-hybrid triple quadrupole linear ion trap-mass spectrometry(UPLC-QqLIT-MS) was established for determination of lipophilic marine biotoxins in shellfish. And the 12 lipophilic marine biotoxins in shellfish were surveyed. METHODS: The lipophilic marine biotoxins in homogenized shellfish were ultrasonically extracted by methanol in super-sonic instrument, and cleaned up by solid phase extraction of Strata-X column, and eluted with methanol(containing 0.3% ammonia water). The elution was diluted with water, and cleaned by 0.22 µm millipore filter. The filtrate was separated on a Waters ACQUITY UPLC BEH C_(18) column(150 mm×2.1 mm, 1.7 µm)by gradient elution in 12 minutes with acetronitrile-water(containing 0.01%(V/V) ammonia and 2 mmol/L ammonium formate) as mobile phase, and detected by ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS), identified by electrospray ionization(ESI) in simultaneous scanning mode of positive and negative ions using multiple reaction monitoring, and quantified with external standards. Information dependent acquisition scan function(IDA) combined with enhanced production scan(EPI) was used to confirm the 12 lipophilic marine biotoxins. RESULTS: The calibration curves of 12 lipophilic marine biotoxins showed good linearity in the range of 0.5-50 µg/L with correlation coefficients were 0.9984-0.9999.The detection limits of the method were 0.15-0.29 µg/kg. The recoveries of three spiking levels ranged from 80.0% to 116.0%, and the relative standard deviation(RSD) were 0.6%-6.4%(n=7). CONCLUSION: The method for determination of 12 lipophilic marine biotoxins in shellfish by UPLC-QqLIT-MS was of operation convenience, less interference from impurities and good accuracy, which could meet the requirements for the determination of 12 lipophilic marine biotoxins residues in sea foods.

Phthalate exposure linked to high blood pressure in Chinese children.

BACKGROUND: Exposure to phthalate esters may be linked to the risk of high blood pressure (HBP), but limited evidence is available in Chinese children. OBJECTIVE: To investigate the associations between nine phthalate metabolites (mPAEs) and systolic/diastolic BP, pulse pressure (PP), mean arterial pressure (MAP), and the risk of HBP. METHODS: In this cross-sectional study, a total of 1044 primary school children (6-8 years old) were enrolled from Shenzhen, China, between 2016 and 2017. Nine mPAEs were analyzed from urine using ultra-performance liquid chromatography and tandem mass spectrometry. A multivariable linear regression model was used to explore the associations between phthalate exposure and systolic/diastolic BP, PP, and MAP. A binary logistic regression model was used to examine the associations between phthalate exposure and the risk of HBP. RESULTS: Monomethyl phthalate (MMP) concentrations were significantly higher in HBP children than normal BP children. MMP, monoisobutyl phthalate (MiBP), monobutyl phthalate (MnBP), mono(5-carboxy-2-ethylpentyl) phthalate, mono-[(2-carboxy methyl)hexyl] phthalate (MCMHP), the sum of four short-chain mPAEs (∑LMW), and the sum of all nine mPAEs (∑9mPAEs) were significantly positively associated with increases in systolic BP z-score, while only MMP was significantly positively associated with diastolic BP z-score. MMP, MiBP, MnBP, MCMHP, ∑LMW, and ∑9mPAEs were significantly associated with increases in PP, while MMP and MnBP were significantly associated with increases in MAP. MMP was significantly associated with the risk of HBP, with an odds ratio of 1.87 (95% CI: 1.23, 2.85). CONCLUSIONS: The present study suggests that dimethyl phthalate exposure increases the risk of HBP. And some types of phthalates are associated with elevations in systolic/diastolic BP z scores, PP, and MAP in Chinese children.

Correlation of urine phthalate metabolite levels with blood pressure in first-grade children / 中国学校卫生

Objective@#To explore the correlation between blood pressure and urinary phthalandione, MMP, MEP, MnBP, MiBP, PAEs.@*Methods@#Three schools were selected from Shenzhen, China for the present study. A total of 765 firstgrade students of Han ethnicity were recruited voluntarily from the selected schools during September 2016 to June 2017. They were divided into normal blood pressure (BP) group (lower than P90 group) and high BP group (BP≥P90). Linear and Logistic regression models were used to analyze the relationships between blood pressure and urine phthalate metabolite levels.@*Results@#Urinary MMP and MnBP in students of high BP group were significantly higher than that of students in normal BP group(t=13.12, 3.97, P<0.05). Linear regression models showed that Z score increased when MMP and MnBP levels increased(P<0.05). Logistic regression model suggested that the risk of high BP increased with the increment of MMP level adjusting creatinine, sex, age and BMI(OR=1.47, P<0.05). There was no statistical significance in the differences after adjusting many factors including family income and education level of parents(P>0.05).@*Conclusion@#Urinary phthalate metabolite levels are positively associated with blood pressure in first-grade children.

[Determination of 7 penicilins and penicilloic acids in milk products by high performance liquid chromatography-tandem mass spectrometry].

OBJECTIVE: A high performance liquid chromatography-tandem mass spectrometric method was established for determination of 7 penicilins (cloxacillin, nafcillin, oxacillin, penicillin V, amoxicillin, penicillin G, ampicillin) and their penicilloic acids (cloxacilloic acid, nafcilloic acid, oxacilloic acid, penicilloic acid V, amoxicilloic acid, penicilloic acid G and ampicilloic acid) in milk products. And the 7 penicilins and penicilloic acids in milk products were surveyed. METHODS: The 7 penicilins and penicilloic acids in milk products were extracted by water in super-sonic instrument , precipitated proteins by acetonitrile and degreased fat by n-hexane with liquid-liquid extraction, then the purified solution was concentrated by nitrogen, dissolved with acetonitrile-water (10 + 90, V/V) and cleaned by 0.22 µm millipore filter. The filtrate was detected by high performance liquid chromatography-tandem mass spectrometry, identified by electrospray ionization (ESI) in positive mode using multiple reaction monitoring, and quantified with external standards. RESULTS: The calibration curves of 7 penicilins and penicilloic acids showed good linearity in the range of 1.0-200 µg/kg with correlation coefficients were above 0.9992. The detection limits of the method were from 0.03 µg/kg to 0.15 µg/kg. The recoveries of three spiking levels ranged from 80.0% to 110.0%, and RSDs of 7.06% or less were obtained. CONCLUSION: The method for determination of 7 penicilins and penicilloic acids in milk products by HPLC-MS/MS was of operation convenience, less interference from impurities and good accuracy, which could meet the requirements for the determination of 7 penicilins and penicilloic acids residues in milk products.

[A static mechanical comparison between two transarticular internal fixation techniques in the lower cervical spine].

OBJECTIVE: To compare static mechanical difference between two transarticular internal fixation techniques in the lower cervical spine. METHODS: Ten fresh human cadaveric cervical spines were harvested. On one side, transarticular pedicle screws were placed at the C3-4, C5-6, and C7-T1 levels, and transarticular screws were placed on the other side. The screw insertion technique at each level was randomized for right or left. The starting point for transarticular pedicle screw insertion was located at the midpoint of the inferolateral quadrant of the lateral mass and the direction of the screw was about 50 degrees caudally in the sagittal plane and about 45 degrees medially in the axial plane, and the starting point for transarticular screw insertion was 1 mm medial to the midpoint of the lateral mass, aiming in a 15 - 20 degrees caudally and 35 - 40 degrees lateral position. After screw placement, each set of vertebral bodies were mounted in a custom jig for axial pullout testing using a servohydraulic testing machine. The load-displacement curves were obtained for each screw pullout. RESULTS: The mean pullout strength for the transarticular pedicle screws was 668 N. This compares with 414 N for the transarticular screws (P < 0.05), but there was not significant difference statistically between different cervical levels (P > 0.05). CONCLUSION: The static mechanical strength of transarticular pedicle screws is superior to the transarticular screws, and the transarticular pedicle screw fixation has the biomechanical feasibility of clinical application.