| Part 1 Simultaneous determination of five neonicotinoid residues in soil of urban public green area by online SPE-HPLC systemsObject: An online solid phase extraction-high performance liquid chromatography(SPE-HPLC)method was established for the determination of five neonicotinoid pesticide residues in soil of urban public green area,including:nitenpyram,thiamethoxam,imidacloprid,acetamiprid,thiacloprid.Method: The target compounds in soil samples were extracted by the mixed solution of dichloromethane and acetonitrile(19:1,v/v)under ultrasonic operation.After centrifugation,the supernatant was concentrated by nitrogen gas,purified with a PEP on-line SPE column(HyperSep? Retain PEP,10 mm× 3 mm,5 ?m).By rotation of the switching valve,with diethylamine solution,acetonitrile as mobile phase,gradient elution,analytes were eluted from the SPE cartridge in the back-flush mode and transferred to the analytical column(Diamonsil C18,250 mm × 4.6 mm,5?m)by right pump of the double ternary liquid chromatography systems.Analytes were determined using DAD detector and quantified by external standard method.Results: The detection limits were 0.005~0.010 mg/kg,and good linear responses of five neonicotinoid residues were observed in the range 0.01~2.00 mg/L(r>0.9999).Detection limits of the method for five neonicotinoid pesticide residues in soil ranged from 0.01~0.02 mg/kg.The recoveries at low,medium and high concentration levels were 72.54%~111.28%,77.99%~110.34%,and 72.70%~119.42%,while RSDs were all lower than 9.64%.Conclusions: The method is simple,rapid and high efficiency,and was successfully utilized to detect five neonicotinoid residues in soil of urban public green area with satisfactory results.Part 2 Simultaneous determination of seven kinds of pesticide residues in soil by online-SPE-HPLC with double detectorsObject: This research,seven pesticide residues in soil,including: carbendazol,thiacloprid,imidacloprid,sulfamethoxaz,nitenpyram,sulfadiazine and sulphaguanidine,have been concentrated and detected with online solid phase extraction-high performance liquid chromatography(SPE-HPLC)method.Method: Both of online-SPE concentration and parameter determination of HPLC-DAD/FLD have been optimized to get the best experimental conditions: the target compounds in soil samples were extracted by the mixed solution of methyl alcohol,acetonitrileand dichloromethane(5:4:1,v/v/v)under ultrasonic operation and concentrated by nitrogen gas,purified with a PEP online SPE column(HyperSep? Retain PEP,10 mm× 3 mm,5 ?m)and analysised by column(Diamonsil C18,250 mm × 4.6 mm,5?m)with diethylamine solution,acetonitrile as mobile phase,gradient elution.Analytes were determined using DAD and FLD detector and quantified by external standard method.Results: The detection limits were 1.1~3.0×10-3 mg/kg(S/N=3),and seven residues had good linear responses(r>0.9999).The recoveries at low,medium and high concentration levels were 71.92%~103.88%,while RSDs were 0.07%~5.67%.Conclusions: The method is simple,rapid and high efficiency,and was successfully utilized to detect seven residues in soil and improve technical soil treatment in the future.Part 3 Establishment and application of a new method for the determination of hydrogen sulfide in plasma by pre-column derivatization-HPLCObject: A pre-column derivation HPLC method has been set up to determination of H2 S in rat plasma for investigating the effect of garlicin on mice with paraquat poisoning.Methods: 24 ICR mice were randomly divided into 4 groups,6 mice in each group,normal control group(Group 1),DATS control group(Group 2),PQ poisoning group(Group 3),DATS intervention group(Group 4).Group 3 and 4 of mice were made into the model of poisoning by pouring PQ(35 mg/kg)into the stomach.In group 2 and 4,DATS(25 mg/kg)was injected by intraperitoneal at 2h,26 h and 50 h later.The same amount of normal saline was injected by intraperitoneal in group 1,3 at the same time.Results: A good linear relationship was obtained in the concentration range from 0.2 to 300.0 nmol/L.The limit of detection for derivatization product was 0.03 nmol/mL.The mean recoveries of plasma samples standard addition test at high,middle and low levels were 94.7%~101.5%,RSDs were not more than 6.86%.In group 3,H2 S was significantly lower than that of group 1(P<0.01).In group 4,H2 S was significantly higher than that of group 3(P<0.05).Conclusion: In conclusion,DATS has a protective effect against PQ-induced decrease of H2 S content in mice.But in need of large-scale,long course of the test to confirm that DATS is safety,and whether it could be used as an auxiliary treatment method for paraquat poisoning patients.Part 4 Study on effects of the garlicin on monoamine neurotransmitters in the brain of paraquat poisoning mice by HPLC-ECDObject: A HPLC-ECD method was established for the determination of five neurotransmitters in cerebral tissues of mice to discuss the protective effects of garlicin(DATS)on the monoamine neurotransmitters(MNTs)of paraquat(PQ)poisoning mice brain tissues.Method:1 Male ICR mice were divided into four groups(n?6)according to their different treatments.The paraquat(PQ)group and the treatment(PQ+DATS)group exposed to 35 mg/kg PQ i.g..The control group and the garlicin(DATS)group were given same volume sterile saline.The garlicin(DATS)group and treatment group administrated with 25 mg/kg DATS i.p.after PQ was given intragastrically for 2h,26 h,50h,PQ group and normal group mice were injected with the same amount of sterile saline.2 The determination was performed on Acclaim 120 Cl8 column with mobile phase consisted of buffer salt(sodium citrate,monopotassium phosphate,sodium heptanesulfonate,EDTA-2Na,diethylamine hydrochloride)-methanol(93:7,v/v)at the flow rate of 0.27 mL/min,and the voltage of electrode was 450 mV.Results:1 Compared with the normal or DATS group,the PQ group produced significant decreases in the quantities of DA and 5-HT.The combination of PQ and DATS resulted in higher amounts of neurotransmitters than administration with PQ alone(P<0.05);2 The addition standard recoveries were 79.8%~103.0%,and the RSDs were lower 10%.Conclusion: DATS can protectrats from PQ-induced decreased the contents of neurotransmitters,which may be associated with its abilities to relieve oxidative damages.The method is sensitive,simple and rapid,and can be used for the determination of 5-HT,DA,5-HIAA,HVA and DOPAC in rat cerebral tissues. |
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