One-step separation of Cu, Fe, Zn and Cd and isotope ratio analysis by MC-ICP-MS for geological samples.

Multi-isotope systems have shown great application potential in tracing geological and environmental processes. In order to obtain the isotopic composition of multiple elements of interest, the common protocol is to separate each element from the matrix by independent procedures, which has some limitations, including poor efficiency, being time-consuming, requiring large samples and being unsuitable for rare samples (e.g., meteorite, lunar soil and atmospheric aerosol samples). In this study, we present an integrated and optimized one-step method to separate Cu, Fe, Zn and Cd from complex matrix elements using the AG MP-1M anion exchange resin. By experimentally optimizing the resin volume, eluent concentration and eluent amount, these target elements can be effectively separated from the matrix elements, such as Cu separation from Ti and Co, Zn separation from Fe and Cd, and Cd separation from Sn. The recoveries of Cu, Fe, Zn and Cd were 100.1 ± 0.8% (2SD, n = 3), 99.8 ± 0.7% (2SD, n = 3), 100 ± 0.8% (2SD, n = 3) and 99 ± 1% (2SD, n = 3), respectively. Moreover, the resolution (R) between the elements of interest and interfering elements was in the range of 1.8-28.1. The process blanks of Cu, Fe, Zn and Cd were 1-1.6 ng, 62-70 ng, 2.1-3 ng and 66-74 pg, respectively. The obtained isotope ratios for the standard reference materials agreed well with the published values. Meanwhile, we have reported the Cu, Fe and Zn isotope ratios of six soil and sediment standard reference materials, namely NIST 2711a, GSS-1, GSD-5a, GSD-7a, GSD-12 and GSD-23, for the first time. These new data can be used for the intercalibration and quality control of soils and sediments in other laboratories. The one-step separation of Cu, Fe, Zn and Cd shows obvious economic and efficiency advantages, making it suitable for the simultaneous separation of multiple elements of interest in geological samples.

Electrothermal Desolvation-Enhanced Dielectric Barrier Discharge Plasma-Induced Vapor Generation for Sensitive Determination of Antimony by Atomic Fluorescence Spectrometry.

A novel simple electrothermal desolvation-enhanced dielectric barrier discharge plasma-induced vapor generation (ETD-DBD-PIVG) method has been developed for sensitive Sb determination by atomic fluorescence spectrometry (AFS). In our proposed ETD-DBD-PIVG, 20 µL sample solution was dried first; then, the resulting solution residue was directly converted into molecular volatile species efficiently through the interactions with hydrogen-doped DBD plasma; and finally, it was transported to AFS for detection. It was found that the desolvation process could greatly enhance Sb vapor generation, and the Sb fluorescence signal intensity is almost independent of its speciation, where comparable sensitivity is achieved for Sb(III) and Sb(V), enabling efficient total Sb detection without pre-reduction. Influencing parameters were evaluated in detail, including heating time, discharge gap, solution pH, and flow rates of argon and hydrogen, as well as coexisting ion interference. Under optimized conditions, the limit of detection was calculated as 0.86 µg L-1 (17.2 pg) for Sb. The accuracy of the proposed method was validated by the analysis of certified reference materials of simulated natural water samples and several river water samples. Compared with conventional hydride generation, the new ETD-DBD-PIVG offers an alternative green vapor generation technique with several advantages: (1) it eliminates the use of a sample flow system (e.g., no use of any syringe or peristaltic pump); instead, 20 µL of a sample is directly pipetted onto the glass plate for analysis; (2) it greatly simplifies the sample pretreatment steps as no pre-reduction process is needed; (3) it is sensitive and suitable for volume-limited sample analysis: efficient Sb vapor generation without chemical reducing reagents in ETD-DBD-PIVG enables Sb detection with an absolute limit at the picogram level. All the results demonstrate that the proposed method provides a simple, green, and sensitive method for Sb determination and it can also be extended to other elements such as Cd and As.

Direct and Sensitive Determination of Antimony in Water by Hydrogen-Doped Solution Anode Glow Discharge-Optical Emission Spectrometry Without Hydride Generation.

In the present work, a novel, simple, and sensitive method for the direct determination of trace Sb in water samples was developed based on hydrogen-doped solution anode glow discharge-optical emission spectrometry (SAGD-OES). It was found that the vapor generation and excitation of Sb occurred simultaneously in the SAGD, contributing to the significant improvement in the sensitivity of Sb as compared with normal pure He-operated SAGD or solution cathode glow discharge. Besides, the proposed hydrogen-doped SAGD-OES could be operated even at pH = 14, which could reduce the interference of coexisting ions as many metal ions could be precipitated and removed. Our results demonstrated that the proposed method offered good tolerance to the interferences of Li, Na, Ca, Mg, Fe, Ni, Mn, and Zn ions even at a concentration of 50 mg L-1. Under optimized conditions, the limit of detection of Sb was 0.85 µg L-1, which was comparable to that of microplasma sources coupled with conventional hydride generation. The linearity of the Sb calibration curve reached R2 > 0.999 in the 5-5000 µg L-1 range. Finally, the accuracy of the proposed method was validated by the determination of certified reference materials [GSB 07-1376-2001 (1) and (2))] and real water samples. The proposed low-power (6 W), green, sensitive, rapid, and robust method provides a promising approach for on-site trace Sb analysis and may also be extended to other elements.

Development of a Portable Method for Serum Lithium Measurement Based on Low-Cost Miniaturized Ultrasonic Nebulization Coupled with Atmospheric-Pressure Air-Sustained Discharge.

An accurate, rapid but cheap, and portable method for monitoring of serum lithium (Li) is highly desirable for mental patients who take Li medicine for treatment. Conventional techniques are usually bulky, costly, and cannot provide on-site real-time measurements. Herein, a miniaturized, reliable, cost-effective, and portable optical emission method for rapid and sensitive determination of serum Li was developed based on a combination of miniaturized ultrasonic nebulization (MUN) and a low-power (≈22 W) atmospheric-pressure air-sustained discharge (APAD) excitation source. The proposed method eliminates the use of any compressed gas or pump and can achieve serum Li detection within 40 s with low sample consumption (less than 20 µL serum). Except for dilution with water, no extra treatment is needed for serum Li analysis by MUN-APAD-OES. In addition, it offers a significant advantage of good tolerance to the coexisting high concentration of Na, K, Ca, and Mg, which is in contrast with the obvious matrix effect encountered in conventional inductively coupled plasma optical emission spectrometry (ICP-OES). Different operating parameters affecting the performance of MUN-APAD-OES were evaluated. Under optimized conditions, the detection limit of Li (670.8 nm) was calculated to be 0.6 µg L-1 (6 µg L-1 in serum). Finally, the accuracy of the proposed method was validated by the analysis of two certified reference materials (Seronorm serum L-1 and L-2 RUO), six real human serum samples, and eight real animal serum samples. All of the results indicate that the low-cost and low-power MUN-APAD-OES provides a promising reliable method for on-site serum Li measurement and may also be extended to other elements.

Stable isotope fractionation of cadmium in the soil-rice-human continuum.

Consumption of rice (Oryza sativa) grain is a major pathway by which humans are exposed to Cd, especially in non-smoking Asian populations. Although the stable isotope signatures of Cd offer a potential tool for tracing its sources, little is known about the isotopic fractionation of Cd across the entire soil-rice-human continuum. Cadmium isotope ratios were determined in field soils, rice grain, and human urine collected from two Cd-contaminated regions in southern China. Additionally, Cd isotopic fractionation in rice plants was investigated using two transgenic plants differing in Cd uptake and accumulation. Analysis of isotope ratios revealed a preferential enrichment of the heavy Cd isotopes from soil to rice grain (δ114/110Cdgrain-soil = +0.40‰) and from grain to urine (δ114/110Cdurine-grain = +0.40‰) in both regions. The first increase was mainly caused by partitioning between the soil solid phase and the soil solution, with heavier Cd preferentially enriching in the soil solution. Within the rice plant, we identified multiple processes that alter the isotope ratio, but the net effect throughout the plant was comparatively small. Cd fractionation in humans is presumably due to the preferential enrichment of heavier Cd isotopes by metal transporters DMT1 and ZIP8 (responsible for the absorption of Cd into body from the foods). These findings provide important insights into the Cd isotopic fractionation through the soil-rice-human continuum and are helpful for tracing the sources of Cd.

Effects of intravenous lidocaine, dexmedetomidine and their combination on postoperative pain and bowel function recovery after abdominal hysterectomy.

BACKGROUND: Intravenous (IV) lidocaine and dexmedetomidine have been shown to decrease postoperative pain, reduce analgesic consumption and facilitate return of bowel function. We investigated whether lidocaine combined with dexmedetomidine infusion was superior in controlling pain and recovery of bowel function. METHODS: A total of 240 women undergoing elective abdominal hysterectomy were randomly assigned into four groups: group CON received normal saline infusion, group LIDO received lidocaine infusion (1.5 mg/kg loading, 1.5 mg/kg/h infusion), group DEX received dexmedetomidine infusion (0.5 µg/kg loading, 0.4 µg/kg/h infusion) and group LIDO+DEX received lidocaine (1.5 mg/kg loading, 1.5 mg/kg/h infusion) and dexmedetomidine infusions (0.5 µg/kg loading, 0.4 µg/kg/h infusion). The primary outcome was visual analog pain scale (VAS) scores at 1, 4, 8, 12, 24, and 48 hours after surgery. The secondary outcomes included time to first bowel sounds and flatus, postoperative fentanyl requirement and perioperative propofol and remifentanil consumption. RESULTS: The VAS scores were significantly lower in groups LIDO and DEX at 4, 8, and 12 hours compared to group CON after surgery (P<0.01). The VAS scores were also significantly lower in group LIDO+DEX at 1, 4, 8, 12, and 24 hours compared to other three groups after surgery (P<0.01). Time to first bowel sounds and flatus was significantly shorter in groups LIDO and LIDO+DEX than groups CON and DEX (P<0.01). Postoperative fentanyl requirement was significantly lower in group LIDO at 1 and 4 hours and in group DEX at 1, 4, 8 hours compared to group CON after surgery (P<0.01). Postoperative fentanyl requirement was also significantly lower in group LIDO+DEX at 1, 4, 8, 12, 24 and 48 hours compared to other three groups after surgery (P<0.01). Propofol and remifentanil consumption was significantly lower in groups LIDO, DEX and LIDO+DEX compared to group CON (P<0.01). CONCLUSIONS: Lidocaine combined with dexmedetomidine infusion significantly improved postoperative pain and enhanced recovery of bowel function undergoing abdominal hysterectomy.

[Application of argon-nitrogen mixed gas inductively coupled plasma in elements and isotopes analysis].

To improve the precision and accuracy of elements and isotopes analysis in traditional Ar-ICP, the addition of nitrogen in ICP has been widely used. The present review focused on the discussions of the basic physical and chemical properties of the Ar-N2 mixed gas inductively coupled plasma and the mechanisms of the special nature of Ar-N2 mixed gas plasma. The applications of Ar-N2 inductively coupled plasma in spectral analysis and mass spectrometry analysis in the past 40 years were summarized. The authors also give an overall outlook on the application of this technology.

[Determination of gold and silver in twenty plants from the copper mining area by inductively coupled plasma-mass spectrometry].

The preconcentration and determination of gold and silver in twenty plants from the copper mining area by ICP-MS was described. The plant samples were decomposed by dry-ashing and aqua regia. 107Ag, 109Ag and 197Au were chosen as determining isotopes and 103Rh and 203Tl were chosen as internal standards. The conditions of sample digestion were elected and the interferences on instrument measurement were eliminated through the experiments. The detection limits of method were 0.048 and 1.06 ng x g(-1) for Au and Ag. The precisions (n=5) were between 0.85% and 9.05% RSD, and the recoveries were between 93.6%-101.6% (Au, Ag). The method is sensitive quick,simple and has been applied to the analysis of gold and silver in plants from the copper mining area. Under the given analytical conditions, the results showed that the contents of the Au and Ag varied in these diferent plants, the ranging between 0.181-0.99 ng x g(-1) for Au and 280-2150 ng x g(-1) for Ag respectively. The geochemical anomalies on Ag were discovered in Pteris, Dicranopteris pedata and Bolbitis heteroclita, which can be regarded as prospecting effective indicator plants.

Protective Effects of Peroxisome Proliferator-Activated Receptor-α Agonist, Wy14643, on Hypoxia/Reoxygenation Injury in Primary Rat Hepatocytes.

This study investigates the effects and possible mechanism of an agonist of PPARα, Wy14643, on primary hepatocytes subjected to H/R injury in rats. H/R induced a significant increase ALT, AST, MDA in the culture medium and ROS in the hepatocytes. These effects were reversed by pretreatment with Wy14643 in the dose-dependent manner. The activity of SOD and the level of GSH in the hepatocytes were decreased after H/R, which were increased by Wy14643 pretreatment. Moreover, the mRNA expressions of PPARα significantly increased in H/R+Wy14643 groups when compared with that in H/R group. A PPARα agonist, Wy14643, exerts significant protective effect against H/R injury in primary hepatocytes via PPARα activation and attenuating oxidative stress.

[Quantitative determination of elements in plant samples by laser ablation inductively coupled plasma mass spectrometry].

The 193 nm excimer laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used for the quantification of 13 elements (Li, B, Na, Mg, Al, K, Ca, Cr, Mn, Fe, Ni, Cu and Ba) in the plant samples (GBW070602, GBW070605 and GBW08514). Indium standard solution with known concentration was mixed into samples and used as an internal standard. Afterwards the samples were ground again and pressed to disks. NIST SRM 610 glass material reference standard was used as the external standard in the LA-ICP-MS measurements. In contrast to longer wavelength ablation techniques, in this experiment a round crater with low deposits could be achieved during ablation. And another study was done on the effect of homogenization over the powder disk It was clearly shown that the analytical results under the condition of 193 nm LA-ICP-MS, using NIST SRM 610 as the external standard for analysis of pressed disk of plant sample, are in good agreement with certified values.

Effects of Wy14643 on hepatic ischemia reperfusion injury in rats.

AIM: To investigate the effects and possible mechanisms of Wy14643 on hepatic ischemia-reperfusion (I/R) injury in rats. METHODS: Thirty male Sprague-Dawley rats weighing 220-280 g were randomly divided into five experimental groups: sham group (G1, n=6): a sham operation was performed (except for liver I/R); I/R-untreated group (G2, n=6): rats underwent liver ischemia for 90 min followed by reperfusion for 4 h; and I/R+Wy14643 groups (G3, G4, G5; n=6): after the same surgical procedure as in group 2, animals were pretreated with Wy14643 at the dose of 1, 5 and 10 mg/kg 1 h before ischemia, respectively. Hepatic ischemia-reperfusion (I/R) was induced by clamping blood supply to the left lateral and median lobes of the liver for 90 min, and atraumatic clamp was removed for 4 h reperfusion. Blood samples and liver tissues were obtained at the end of reperfusion to assess serum and hepatic tissue homogenate aminotransferase (ALT), aspartate aminotransferase (AST), myeloperoxidase (MPO), serum interleukin-1beta (IL-1beta) and tumor necrosis factor alpha (TNF-alpha), as well as activity of superoxide dismutase (SOD) and content of malondialdehyde (MDA) in the hepatic tissue homogenate. RESULTS: Hepatic I/R induced a significant increase in the serum levels of ALT, AST, TNF-alpha, IL-1beta and MPO, as well as the levels of ALT, AST and MDA in the liver tissue homogenate, which were reduced by pretreatment with Wy14643 at the dose of 1, 5 and 10 mg/kg, respectively. The activity of SOD in the liver tissue homogenate was decreased after hepatic I/R, which was enhanced by Wy14643 pretreatment. In addition, serum and liver tissue homogenate ALT and AST in the Wy14643 10 mg/kg group were lower than in the Wy14643 1 mg/kg and 5 mg/kg groups, respectively. CONCLUSION: Wy14643 pretreatment exerts significant protection against hepatic I/R injury in rats. The protective effects are possibly associated with enhancement of anti-oxidant and inhibition inflammation response.

[Determination method with hydride generation and inductively coupled plasma-mass spectrometry].

This article describes the basic principles and advantages as well as disadvantages of hydride generation-inductively coupled plasma-mass spectrometry, over other analytical techniques commonly used for elements which can generate gaseous covalent hybrids. It mainly consulted recent references, including several past literatures.