A mild rapid method for the determination of Pb in grain was established by diluted acid extraction and direct sampling detection with graphite furnace atomic absorption spectrophotometer(GF-AAS). Some factors, such as the grain size, nitric acid concentration, extraction time, solid, liquid proportion, and the instrument conditions were optimized. The results indicated that, at room temperature, the extraction rate of Pb in grain by diluted nitric acid was between 92. 14% and 94. 75%, and the average recoveries of Pb in grain extract reached 91. 65%-94. 58%, the precision of method was less than 5%, and the method detection limits and quantification limits were 0. 64 μg/L and 2. 14 μg/L, respectively, meanwhile, the extraction time was shorten to no more than 30 min. Compared with the results pretreated by microwave digestion and determined by GF-AAS, the detection values obtained by diluted acid extraction had no significance difference (p<0. 1).

Aliquat 336 functionalized chelating adsorbent derived from chitosan for enrichment and separation of Y(Ⅲ) were investigated by static adsorption method. The adsorption of Y(Ⅲ) was greatly influenced by the pH of solution, and reached maximum at 20 ℃ using 90 mg/L Y(Ⅲ) at pH 4. 9, and the adsorption of Y(Ⅲ) followed a pseudo-second-order kinetics model and the Langmuir isotherm model. The reduction of Y(Ⅲ) adsorption with the increasing of temperature meant that the adsorption process was exothermic. XPS analysis demonstrated that both cations and anions of the adsorbent were involved in adsorption process, thereby resulting in an improved adsorption of Y(Ⅲ). The adsorbent was thus efficient for enrichment and separation of rare earths from waste rare earth phosphor.

Graphene/Room temperature ionic liquids ( GN/IL ) nanocomposite was prepared by grinding graphene and ionic liquid 1-butyl-3-methylimidazolium bromide ( BMIMPF6 ) which mixed together in appropriate proportion. Atomic force microscopy ( AFM ) was utilized to characterize the formation of the GN-ILs. Due to the synergistic effect between ionic liquids and graphene, the nanocomposite exhibited excellent performance toward H2 O2 reduction. A novel uric acid ( UA) electrochemical sensor was fabricated based on uricase-GN/IL modified glassy carbon electrode. The experimental results showed that the response displayed a good linear response toward UA in the concentration range from 0. 002-4. 5 mmol/L. The corre1ation coefficient was 0. 995 and the detection limit was 0. 85 μmol/L. The easily prepared electrochemical sensor had favorable stability and selectivity and could be applied to the quick determination of UA in human serum, thus providing a new UA detection method for clinical trial.

A rapid headspace gas chromatography tandem mass spectrometric ( HS-GC/MS ) method was established for the analysis of volatile fatty acids ( VFAs ) in the feces. Feces were suspended by 6%phosphoric acid aqueous solution (1:2 m/V) and sealed in the headspace bottle for HS-GC/MS analysis. The HS-GC/MS method was optimized as follows: agitator temperature ( temp. ):80 ℃, syringe temp.:80 ℃, sample incubation time: 30 min, injection: 1 mL without split-flow. The chromatographic separation was performed on a DB-FFAP capillary column (30m×0. 25 mm×0. 25 μm) with injection port temp.:250 ℃. The temperature program ( initial temp. at 50 ℃ within first 1 min, and raised to 200 ℃ by 10 ℃/min) was employed by fixing the flow of carrier gas (high purity helium) at 1. 0 mL/min. The electron energy at -70 eV for electron impact ( EI ) ionization, ion source temp.: 250 ℃, transfer line temp.:280 ℃, the voltage of electron multiplier at 0. 95 kV. The spectra were recorded in the range of m/z 33-200 for full scan. The established HS-GC/MS method could be applied to analyze VGAs in the feces from human and rat appropriately. There are nine VFAs identified in the feces from human, and eight VFAs detected in the feces from rat by retrieving the NIST library, comparing with the standards and analyzing the MS data. Furthermore, the relative percentage contents of acetic acid, propionic acid and butyric acid accounted for roughly 85% of all VFAs by area normalization. The method is simple and sensitive, and it can be used to rapidly detect VFAs in the feces from human and rat.

A high performance liquid chromatography-tandem mass spectrometric( HPLC-MS/MS) method was developed for the simultaneous determination of four phenolic and salicylanilide anthelmintics including nitroxinil, oxyclozanide, closantel and rafoxanide in cattle and ovine tissues. Muscle, liverand kidney were extracted with acetonitrile-acetone(60:40, V/V)and fat with 1% triethylamine in acetonitrile, then the extract was purified with MAX solid-phase extraction column. Qualitative and quantitative analysiswas achieved by HPLC-MS/MS undernegative multiple reaction monitoring ( MRM) mode. Good correlation coefficients were obtained (R>0. 99) in the concentration range of 1-100 μg/L. The limits of detection (LOD) and limits of qualification (LOQ) for the four compounds were 1 and 2. 5 μg/kg, respectively. The mean recoveries at the four levels of LOQ, 0. 5 maximum residue limit (MRL), MRL, 2MRL were between 71% and 112%,with the intra-day relative standard deviation(RSD)in the range of 1. 1%-14. 0%and inter-day RSD in the range of 6. 4%-14. 7%. Forty samples from the market were analyzed with the method, only two samples were found to show phenolic and salicylanilide anthelmintics residues.

A method based on ultra performance liquid chromatography-tandem mass spectrometry ( UPLC-MS/MS) has been proposed for the determination of coccidiostat residues in chicken skin and fat. The sample was extracted with the combination of methanol, acetonitrile, and acetic acid, and cleaned-up by Sep-Pak tC18 solid phase extraction cartridge. Data acquisition under positive electrospray mode was performed by applying multiple reaction monitoring for both identification and quantification. The limits of detection and quantification for halofuginone and robenidine were 7 μg/kg and 20 μg/kg, respectively. The limit of detection of salinomycin, monensin, narasin, maduramicin, and lasalocid was 5 μg/kg, and limit of quantification was 15 μg/kg. The recovery was 75% to 110% in the spiked concentration range from 15 μg/kg to 200 μg/kg, with intra-day precision lower than 12. 8%, and inter-day precision lower than 13 . 4%.

A method was developed for the determination of four sulfa antibiotics in groundwater, soil and excreta using solid phase micro extraction disks coupled with high performance liquid chromatography. The influence of eluent, different solid phase micro extraction membranes on the recovery of sulfa antibiotics in groundwater was investigated and it was found that when using the mixture of methyl alcohol and 1 . 0% formic acid as eluent, HLB ( divinyl benzene-N-vinyl pyrrolidone polymer ) as extraction membranes, an optimal enrichment effect was obtained. Different pretreatment methods for the 3 kinds of samples abovementioned were also examined. It was found that the signal response values obtained by using mixture of methyl alcohol and 1 . 0% formic acid as base solution of standard or sample solution was higher 8-10 times than that by using methyl alcohol only. Under the optimal conditions, good linear relationships were obtained in the sulfa antibiotics concentrations of 0 . 005-10 . 0 mg/L with the correlation coefficients>0 . 9999;The detection limits of sulfathiazole ( ST ) , sulfadiazine ( SM ) , sulfamethazine ( SM2 ) , sulfamethoxazole ( SMX ) were 1 . 08 , 3. 56, 4. 63 and 1. 84 ng/L(S/N=3), respectively. The enrichment factors for four sulfa antibiotics were 4000 times with solid phase micro extraction disks. The RSD of matrix spiked samples were 0. 1%-0. 4%(n=7). The proposed method was applied to the determination of the four sulfa antibiotics in groundwater, soil and excreta with spiked recoveries of the four sulfa antibiotics in the range of 69 . 80%-117 . 60%.

A high performance liquid chromatography-tandem mass spectrometric method ( HPLC-MS/MS ) was developed for the simultaneous determination of 31 kinds of triazine herbicides in farmland soils. Samples were extracted by accelerated solvent extraction ( ASE ) and purified by Oasis MCX solid phase extraction ( SPE) cartridges, and then analyzed by HPLC-MS/MS in multiple reaction monitoring ( MRM) mode with positive electrospray ionization. The analytical column was Phenomenex Luna C18 ( 150 mm í 2. 0 mm í3 μm) and the mobile phases were acetonitrile and water containing 0. 1% (V/V) formic acid. The limits of detection (S/N≥3) were 0. 008-0. 440 μg/L. All of the triazine herbicides had good linear responses with r≥0 . 996 and the average recoveries in the spiked levels of 0 . 40-40 . 0 μg/kg ranged from 76 . 9%-102 . 0%with the RSDs of 3 . 4%-10 . 3%. The HPLC-MS/MS method had been applied for the detection of the triazine herbicide residues in farmland soils from Shenyang region and the results showed that atrazine, simazine, prometryne and atrazine-desethyl were the main triazine herbicides in the region.

Imaging of trace metal distribution in the cadmium ( Cd) hyperaccumulator Indian mustard by laser ablation inductively coupled plasma-mass spectrometry ( LA-ICP-MS ) was typically performed using spatial resolutions of 25 μm. Indian Mustard was submitted to 50 mol/L Cd for 14 days exposure and analysed using Nd:YAG laser (213 nm) . Intensities of 13 C, 34 S, 39 K, 44 Ca, 66 Zn, 111 Cd, 65 Cu and 31 P were measured by ICP-MS to study elemental distribution. Preferential Cd accumulation in vascular bundles was observed in stem tissue, whereas Cd was mainly localized to the mesophyll and vascular cells. The high relationship between Ca and Cd distribution indicated that the two elements had a very similar pathway. In vivo analytical method developed in this work was useful to study spatial element distribution across stem samples and had great potential for applications in other areas of plant pathology research.

HPLC-ICP-MS method was established to separate AsB, As(Ⅲ), monmethyl arsenic ( MMA ) , dimethyl arsenic ( DMA ) and As(V) in rat viscera. Ultrasonic water bath extraction was used for sample pretreatment. Dionex IonPac AS19 anion-exchange column and 20 mmol/L (NH4)2CO3(pH=9. 7) were used to analyze arsenic species in rat liver and kidney after realgar infected. The results showed that the method was not interfered by 40 Ar35 Cl+ peak, the linear ranges for five arsenic species were all between 1 and 300 μg/L with linear coefficients more than 0. 9990, and the detection limits were between 0. 3 and 0. 5 μg/L. The relative standard deviations ( RSDs) for the determination of five species were less than 5% and the recoveries were between 83. 8% and 111. 7%. After speciation analysis, DMA, As(Ⅲ) and unknown compound 2 were found in liver;DMA, MMA, As(Ⅲ), unknown compound 1, unknown compound 2 and unknown compound 3 were found in the kidney. The results indicated that this method could be used for arsenic species analysis of realgar metabolism.