ABSTRACT
To ensure the quality and safety of Panax notoginseng, a method for the simultaneous determination of 10 mycotoxins in Panax notoginseng was developed using ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The sample was extracted with acetonitrile and purified by HLB multifunction cleanup column. The separation was performed on a Phenomenex Kinetex XB-C18 column by gradient elution using methanol and 5 mmol·L(-1) ammonium acetate as mobile phase. The targeted compounds were detected in MRM mode by mass spectrometry with electrospray ionization (ESI) source operated in both positive and negative ionization modes. The linear relationships of the 10 mycotoxins were good in their respective linear ranges. The correlation coefficients (r) ranged from 0.9981 to 1.0000. The LOQs of the 10 mycotoxins were between 0.15 and 8.6 μg·kg(-1). The average recoveries ranged from 73.8% to 107.0% with relative standard deviations (RSDs) of 0.10%-10.9%. The results demonstrated that the proposed method was sensitive and accurate, and suitable for the mycotoxins quantification in Panax notoginseng.
ABSTRACT
In order to simultaneously remove carbon and nitrogen from organic-rich wastewater, we used an up-flow anaerobic sludge bed/blanket (UASB) reactor that was started up with anammox with high concentration of carbon and nitrogen by gradually raising the organic loading of influent. We optimized the removal of nitrogen and carbon when the chemical oxygen demand (COD) concentration varied from 172 to 620 mg/L. During the entire experiment, the ammonium and total nitrogen removal efficiency was higher than 85%, while the average COD removal efficiency was 56.6%. The high concentration of organic matter did not restrain the activity of anammox bacteria. Based on polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and tapping sequencing analyses, the Planctomycete, Proteobacteria, Chloroflexi, Chlorobi bacteria are detected in the UASB reactor, which indicated complex removal pathway of carbon and nitrogen coexisted in the reactor. However, a part of Planctomycete which referred to anammox bacteria could tolerate a high content of organic carbon, and it provided help for high performance of nitrogen removal in UASB reactor.
Subject(s)
Ammonia , Chemistry , Biological Oxygen Demand Analysis , Bioreactors , Carbon , Chemistry , Nitrogen , Chemistry , Sewage , Waste Disposal, Fluid , Methods , Wastewater , ChemistryABSTRACT
To study the enrichment regulation of anammox bacteria during the whole start-up process of anammox reaction, two reactors with addition of carries of Spherical Plastic (SP) and Bamboo Charcoal (BC) and one without carrier (CK) were used to start anammox reaction. Then FISH and q-PCR analyses for the growth of all anammox bacteria were conducted during the operational process. The results indicate that the number of anammox bacteria in all reactors increased with time during the whole start-up process, which was consistent with the removal rate of ammonium and nitrite. On day 123 of stable phase, the percent of anammox cells in the sludge of CK, SP and BC accounted for 23.3%, 32.6% and 43.7%, respectively. The number of anammox bacteria 16S rRNA gene copies was (25.64 +/- 2.76) x 10(7), (47.12 +/- 2.76) x 10(7) and (577.99 +/- 27.25) x 10(7) copies g(-1) VSS in the sludge of CK, SP and BC, respectively. Carrier addition could dramatically increase enrichment of anammox bacteria. BC addition significantly increased the anammox bacteria number in the UASB reactor which resulted in the acceleration of the anammox start-up process. In addition, the max specific growth rate and the minimum doubling time were 0.064 d(-1) and 10.8 d in BC reactor. The max specific growth rate of anammox bacteria in BC reactor was 1.78 times and 1.88 times greater than that in CK and SP reactor, respectively. Therefore, the FISH and q-PCR analyses were suitable for determining the enrichment regulation of anammox bacteria during the start-up time, while a bit of differences in results existed between the two analytical methods due to the difference in analysis targets.