Simultaneous separation and indirect ultraviolet detection of chlorate and perchlorate by pyridinium ionic liquids in reversed-phase liquid chromatography.

A novel approach for the simultaneous separation and indirect ultraviolet detection of chlorate and perchlorate using pyridinium ionic liquids as mobile phase additives in reversed-phase liquid chromatography was developed. Pyridinium ionic liquids and imidazolium ionic liquids as the mobile phase additives were compared. The effects of pyridinium ionic liquids, methanol, column temperature, and detection wavelength on the separation and detection of chlorate and perchlorate were investigated. The role of ionic liquids, retention rules and relevant mechanisms were discussed. Pyridinium ionic liquids mainly acted as ultraviolet absorption reagent and ion-pair reagent. The successful separation and indirect ultraviolet detection of chlorate and perchlorate were achieved by using a common reversed-phase column, 0.2 mmol/L N-octylpyridinium bromide aqueous solution/methanol (90/10, v/v) as mobile phase and at the detection wavelength of 210 nm. The retention times of chlorate and perchlorate were 30.51 and 37.06 min, respectively. The detection limits of chlorate and perchlorate were 0.16 and 0.29 mg/L, respectively. The linearity and repeatability of the method were satisfactory. The approach was used to the analysis of river water samples with accurate and reliable results. This method is easy to popularize due to the use of common reversed-phase column and ultraviolet detector in liquid chromatography.

Ionic liquids as mobile phase additives for determination of thiocyanate and iodide by liquid chromatography.

An analytical method was developed for the simultaneous determination of thiocyanate and iodide by reversed-phase liquid chromatography with UV detection using imidazolium ionic liquids as mobile phase additives. The chromatographic behaviors of the two anions on a C18 column were studied and compared with four types of reagents including imidazolium ionic liquids, pyridinium ionic liquids, 4-aminophenol hydrochloride and tetrabutylammonium as mobile phase additives. The effects of the concentrations of imidazolium ionic liquids, organic solvents and detection wavelength on separation and detection of the anions were investigated. The role of ionic liquids, retention rules and mechanisms were discussed. The separation of the anions was performed on the C18 reserved-phase column using acetonitrile-0.3 mmol/L 1-amyl-3-methylimidazolium tetrafluoroborate (10:90, v/v) as mobile phase, with column temperature of 35°C, flow rate of 1 mL/min and detection wavelength of 210 nm. Under these conditions, the two anions can be completely separated within 6 min. The limits of detection were 0.05 mg/L. The method was applied for the determination of thiocyanate and iodide in ionic liquid samples and iodide drugs, and the spiked recoveries ranged from 97 to 101%. The method is simple, accurate and meets the requirements of quantitative analysis for thiocyanate and iodide.

Separation and indirect ultraviolet detection of ferrous and trivalent iron ions by using ionic liquids in ion chromatography.

A method of simultaneous separation and indirect ultraviolet detection of different valence iron ions Fe2+ and Fe3+ by using ionic liquids as mobile phase additives and ultraviolet absorption reagents on a cation exchange column functionalized with carboxylic acid group was developed. The effects of ionic liquids, organic acids, detection wavelength, etc. on separation and detection of Fe2+ and Fe3+ were investigated and the mechanism was discussed. The pyridinium and imidazolium ionic liquids were not only ultraviolet absorption reagents of indirect ultraviolet detection but also effective components for separating Fe2+ and Fe3+ . The separation and detection of Fe2+ and Fe3+ can be achieved using 0.5 mmol/L pyridinium ionic liquid-1.2 mmol/L methanesulfonic acid as the mobile phase. The determination of Fe2+ and Fe3+ had a good linear relationship in the concentration range of 1-100 mg/L. The limits of detection of Fe2+ and Fe3+ were 0.12 and 0.09 mg/L, respectively. This method was applied to the actual sample detection in the field of medical analysis. The spiked recoveries were between 97.3 and 99.5%, and the relative standard deviations were less than 0.6%. The method is simple, accurate, and reliable, and is an analytical method with universal and practical value.

Imidazolium ionic liquids as mobile phase additives in reversed phase liquid chromatography for the determination of iodide and iodate.

An analytical method for the simultaneous determination of iodide and iodate by reversed phase liquid chromatography with ultraviolet detection using imidazolium ionic liquids as mobile phase additives was developed in this paper. Imidazolium ionic liquids, pyridinium ionic liquids, and common ion pair reagent tetrabutylammonium hydroxide as mobile phase additives were compared. The results indicated that imidazolium ionic liquids as the mobile phase additives were better than any tetrabutylammonium hydroxide or pyridinium ionic liquids. The relevant mechanisms of separation and detection for the anions were discussed. Imidazolium ionic liquids acted as ion pair reagents and ultraviolet absorption reagents in the separation and detection of the anions. The optimized mobile phase of methanol/0.3 mmol/L 1-hexyl-3-methylimidazolium tetrafluoroborate aqueous solutions (12/88, v/v), detection wavelength of 210 nm, and column temperature of 35 °C were used for the determination of iodide and iodate. Under these conditions, the detection limits of iodide and iodate were 0.02 and 0.03 mg/L, respectively. To evaluate the practicability of the method, the determination of iodide and iodate in medicines and beverages was performed by this method. The results are that the spiked recoveries were greater than 95% and RSD was less than 3.0%. The method was simple, accurate, and reliable and could provide a reference for the analysis of iodide and iodate. Graphical abstract The simultaneous determination of iodide and iodate by reversed phase liquid chromatography with ultraviolet detection using imidazolium ionic liquids as mobile phase additives.

Three GPI-anchored alkaline phosphatases are involved in the intoxication of Cry1Ca toxin to Spodoptera exigua larvae.

Glycosylphosphatidylinositol (GPI)-anchored alkaline phosphatase (ALP) isoforms are crucial for the intoxication of crystal proteins (Cry) to several insect species. We cloned five SeALPs from the larval midgut of Spodoptera exigua, a major pest of many crops. All five SeALPs contain a signal peptide at the N-terminus, a phosphatase domain, and a GPI-anchor site at the C-terminus. Additionally, the sequences encode two or three potential N-glycosylation sites. The five SeALPs were highly expressed at the larval stage, especially in the larval gut or Malpighian tubules. Ingestion over four consecutive days of double-stranded RNAs (dsRNAs) targeting SeALP1, SeALP2, SeALP3, SeALP4, and SeALP5 significantly reduced the corresponding mRNA levels by 60.0%, 40.0%, 65.6%, 48.1%, and 69.1% respectively, compared with the levels in control larvae that fed on non-specific dsRNA (dsEGFP). When larvae that previously ingested phosphate buffered saline (PBS)-, dsEGFP-, or five dsSeALPs-overlaid diets were then exposed to a diet containing Cry1Ca, the larval mortalities after six days were 70.0%, 71.8%, 49.1%, 54.9%, 65.3%, 52.5%, and 77.4%, respectively. ANOVA analysis revealed that the larvae that previously fed on the dsSeALP1-, dsSeALP2-, and dsSeALP4-overlaid diets had significantly lower mortalities than those that previously ingested the PBS-, dsEGFP-, dsSeALP3- and dsSeALP5-overlaid diets. The results suggest that SeALP1, SeALP2 and SeALP4 are involved in the intoxication of Cry1Ca to S. exigua larvae.

Clinical Efficacy of Posterior Percutaneous Endoscopic Unilateral Laminotomy with Bilateral Decompression for Symptomatic Cervical Spondylotic Myelopathy.

OBJECTIVE: To compare the clinical efficacy of posterior percutaneous endoscopic unilateral laminotomy (PPEUL) and anterior cervical decompression and fusion (ACDF) in the treatment of single-segment spondylotic myelopathy (CSM). METHODS: This is a retrospective research, from January 2017 to December 2019, 30 cases were included in the PPEUL group and 32 cases were included in the ACDF group. The operative duration, blood loss, length of stay, complications, Japanese Orthopaedic Association (JOA) score, visual analogue scale (VAS) score, MacNab classification and imaging data were collected preoperatively, postoperative 1-week, final follow-up and statistically analyzed. RESULTS: The surgery was completed successfully on all patients, and there were no serious complications, such as nerve or spinal cord injury or infection. In the PPEUL and ACDF groups, the operative duration were 56.63 ± 1.40 and 65.21 ± 2.45 min, the intraoperative blood loss were 51.69 ± 3.23 and 50.51 ± 5.48 mL, and the hospitalization duration was 5.75 ± 1.43 and 6.38 ± 2.16 days. The follow-up period in the PPEUL and ACDF groups was 24.96 ± 1.12 months and 25.65 ± 1.45 months, respectively. There was no significant difference in intraoperative blood loss between the two groups, but the hospitalization and operative durations in the PPEUL group were significantly shorter than those in the ACDF group (P < 0.05). The VAS scores at postoperative 1 week and final follow-up were significantly improved compared with those before surgery. The JOA scores at postoperative 1 week and final follow-up were significantly improved compared with those before surgery, but there was no significant difference between the two groups at the last follow-up. The intervertebral disc height of the adjacent segment at the last follow-up was significantly lower in the ACDF group than in the PPEUL group (P < 0.05), but there was no significant difference between the two groups in the intervertebral disc height of the surgical segment (P > 0.05). The rate of excellent and good results was 90.0% and 87.5%, respectively. Postoperative cervical CT and MRI showed that the spinal canal was fully decompressed and spinal cord compression was relieved. CONCLUSION: PPEUL has the advantages of reduced trauma, rapid recovery and remarkable curative efficacy, so it is a new choice for the treatment of CSM.

Porous {P6Mo18O73}-type Poly(oxometalate) Metal-Organic Frameworks for Improved Pseudocapacitance and Electrochemical Sensing Performance.

{P6Mo18} poly(oxometalate) (POM) clusters have huge steric hindrance and limited active oxygen atoms, which make them difficult to combine with metal-organic units to form three-dimensional (3D) porous structures. Therefore, functionalization of such POMs has always been a bottleneck that is difficult to break through. In this study, {P6Mo18} POM was successfully grafted on a lock-like metal-organic chain to generate a multiporous coordination polymer, [{Na(H2O)(H2btb)}{Cu4I(H2O)(pz)5Cl}{H2Sr⊂P6Mo2VMo16VIO73}]·3H2O (1) (pz = pyrazine; btb = 1,4-bis(1,2,4-triazole) butane). Meanwhile, a zero-dimensional (0-D) control compound with only btb ligands as counterions, (H4btb)[H4Sr⊂P6Mo2VMo16VIO73]·3H2O (2), was also obtained via a hydrothermal reaction. Compound 1 represents the first basket-type 3D poly(oxometalate) metal-organic framework (POMOF) assembly, which possesses interpenetrating pores and complex topology. 1-GO-CPE displays improved supercapacitor (SC) performance (the specific capacitance of 929.4 F g-1 at a current density of 3 A g-1 with 94.1% of cycle efficiency after 5000 cycles) compared with 2-GO-CPE and most reported POMOF electrode materials, which may be due to the outstanding redox capability of basket-POM, introduction of metal-organic chains, intersecting pores, and excellent conductivity of graphene. An asymmetric SC device with 1-GO-CPE as the negative electrode exhibits an energy density of 29.7 Wh kg-1 with a power density of 3148.2 W kg-1 and long-lasting cycling life. In addition, 1-GO-GCE as an electrochemical sensor responds to dopamine (DA) at a voltage of 0.40 V and shows lower detection limits (0.19 µM (signal-to-noise ratio (SNR) = 3)), higher selectivity, and good reproducibility in the linear range of 0.56 µM to 0.24 mM. The ability to accurately detect the content of DA in biological samples further proves the feasibility of the sensor in practical applications.

The Spodoptera exigua (Lepidoptera: Noctuidae) ABCC2 Mediates Cry1Ac Cytotoxicity and, in Conjunction with Cadherin, Contributes to Enhance Cry1Ca Toxicity in Sf9 Cells.

In insects, the mode of Cry1A toxins action has been studied in detail and many receptors that participate in the process are known. Recent evidence has revealed that an ABC transporter (ABCC2) is involved in conferring resistance to Cry1A toxins and that ABCC2 could be a receptor of Cry1A. However, it is not known whether Cry1Ca interacts with the same receptor proteins as Cry1A. In this study, we report the cloning of an ABC transporter gene, SeABCC2b, from the midgut of Spodoptera exigua (Hübner) larvae, and its expression in Sf9 cells for a functional analysis. The addition of Cry1Ca and Cry1Ac to Sf9 cell culture caused swelling in 28.5% and 93.9% of the SeABCC2-expressing cells, respectively. In contrast, only 7.4% and 1.3% of the controls cells swelled in the presence of Cry1Ca and Cry1Ac. Thus, SeABCC2b-expressing Sf9 cells had increased susceptibility to Cry1Ca and Cry1Ac. Similarly, S. exigua cadherin (SeCad1b) expressed in Sf9 cells caused 47.1% and 1.8% of the SeCad1b-expressing cells to swell to Cry1Ca and Cry1Ac exposure. Therefore, Sf9 cells expressing SeCad1b were more sensitive to Cry1Ca than Cry1Ac. Together, our data suggest that SeABCC2b from S. exigua mediates Cry1Ac cytotoxicity and, in conjunction with SeCad1b, contributes to enhance Cry1Ca toxicity in Sf9 cells.