A frozen suspension external calibration strategy for elemental quantitative imaging of fresh plant soft tissues by LA-ICP-MS with cryogenic ablation cell.

A simple and reliable external calibration strategy of LA-ICP-MS for fresh plant soft tissues was developed. The prepared plant suspension was frozen by the designed cryogenic ablation cell and used as external standard for quantitative elemental imaging analysis of fresh plant tissues. The controllable water content of the prepared external standards provides a similar matrix with fresh soft tissues, and a homogeneous elemental distribution could be ensured due to the fine grinding particle sizes. More interestingly, the presence of water increased the signal intensity produced by the suspension by a factor of 1.6 (Pb) to 66.6 (La) compared to that of the pressed cake. The excellent dispersing property and advantage of long-term use were achieved owing to the employment of 0.1% PAANa as suspending agent. A series of plant reference materials were analyzed, and the relative errors of most elements were less than 10 %, indicating that there is a reliable accuracy of the proposed method. The limits of detection (LODs) ranged from 0.1 ng·g-1 (La) to 1279 ng·g-1 (S). This method was used for elemental imaging analysis in rice leaves under arsenic stress, and the results were consistent with previous studies, which mean that the proposed method could provide technical support for researchers in the fields of agriculture and environment.

Direct multi-elemental analysis of cerebrospinal fluid samples by LA-ICP-MS employing an aerosol local extraction cryogenic ablation cell.

A novel method for direct high-throughput analysis of multi-elements in cerebrospinal fluid (CSF) samples by laser ablation inductively coupled plasma mass spectrometry with an aerosol local extraction cryogenic ablation cell (ALEC-LA-ICP-MS) was developed. Microliter-level CSF samples were frozen by a designed cryogenic ablation cell and directly analyzed by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) without time-consuming pretreatment. Compared with the precision obtained at room temperature (20℃), that obtained at low temperature (- 25℃) was significantly improved; the RSDs were reduced from 8.3% (Zn) to 32.6% (Mn) to 2.2% (Pb) to 6.5% (Mn) with six times parallel determination. To meet the analytical requirement of the micro-volume CSF samples, the laminar flow aerosol local extraction strategy was adopted to improve the transmission efficiency of aerosols, and the signal intensity was increased by four times compared with the standard commercial ablation cell. The standard solution with 0.4% bovine serum albumin (BSA) matrix was used as matrix-match external standard, and Rh was added into the samples as internal standard. The limits of detection (LODs) ranged from 0.17 µg·L-1 (Mn) to 8.67 µg·L-1 (Mg). Standard addition recovery experiments and the determination of CRM serum L-1 and L-2 were carried out to validate the accuracy of the method; all results indicated there were excellent accuracy and precision in the proposed method. The matrix-scanning function in the GeoLas software combined with the microwell plate realizes the high-throughput automatic analysis. Twenty-four CSF samples from different patients were determined; the results showed that there might be a correlation between the metal elements in CSF and the diseases, which means that the proposed method has potential in the diagnosis of neurological diseases.

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.

Isotopic Analysis by Laser Ablation Solution Sampling MC-ICP-MS─An Example of Boron.

Using boron as a test analyte, laser ablation (LA) solution sampling multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) is proposed and validated as a fast method for isotopic analysis in natural liquids and digested samples without any prior purification process. We demonstrated that the solution reference standard can be used as a bracketing standard for in situ δ11B analysis in solids. Based on a sensitivity enhancement of 8- to 9-fold, all testing solutions were diluted in a 5% (v/v) NH3·H2O instead of classical 2% (v/v) HNO3. With a discrete and minimal sample solvent loading by the LA sampling strategy, it produces nearly "dry" plasma conditions that tolerate the sample matrix remarkably. The memory effect, one of the most difficult challenges in boron analysis, was dramatically eliminated with only 15 s wash time; thus, each analysis took less than 100 s. No significant matrix effects were observed for varying 50-100% boron concentrations in the samples and varying 20-60% NH3·H2O matrix used for the dilution, as well as for samples doped with a 1/100 synthetic seawater matrix. The external precision of δ11B measurements in NIST 951a was ± 0.30‰ (2SD). Good agreement with the values described in literature studies was achieved for δ11B measurements in eight geological reference materials, with precisions between 0.4 and 0.7‰ (2SD), confirming the accuracy of the proposed method. The proposed method offers advantages of simple sample preparation, fast analysis, and little use of chemical reagents.

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.

Ultrasound-guided bilateral superficial cervical plexus block enhances the quality of recovery of uremia patients with secondary hyperparathyroidism following parathyroidectomy: a randomized controlled trial.

BACKGROUND: Parathyroidectomy has been proposed as a method for reducing parathyroid hormone levels. We evaluated the effects of ultrasound-guided bilateral superficial cervical plexus block (BSCPB) on the quality of recovery of uremia patients with secondary hyperparathyroidism (SHPT) following parathyroidectomy. METHODS: Eighty-two uremia patients who underwent parathyroidectomy and exhibited SHPT were randomly allocated to the BSCPB group or the control group (CON group). The patients received ultrasound-guided BSCPB with 7.5 ml of ropivacaine 0.5% on each side (BSCPB group) or equal amount of 0.9% normal saline (CON group). The primary outcome of the Quality of Recovery-40(QoR-40) score was recorded on the day before surgery and postoperative day 1(POD1). Secondary outcomes including total consumption of remifentanil, time to first required rescue analgesia, number of patients requiring rescue analgesia, and total consumption of tramadol during the first 24 h after surgery were recorded. The occurrence of postoperative nausea or vomiting (PONV) and the visual analogue scale (VAS) scores were assessed and recorded. RESULTS: The scores on the pain and emotional state dimensions of the QoR-40 and the total QoR-40 score were higher in the BSCPB group than in the CON group on POD1 (P = 0.000). Compared with the CON group, the total consumption of remifentanil was significantly decreased in the BSCPB group (P = 0.000). The BSCPB group exhibited longer time to first required rescue analgesia (P = 0.018), fewer patients requiring rescue analgesia (P = 0.000), and lower postoperative total consumption of tramadol during the first 24 h after surgery (P = 0.000) than the CON group. The incidence of PONV was significantly lower in the BSCPB group than in the CON group (P = 0.013). The VAS scores in the BSCPB group were lower than those in the CON group at all time-points after surgery (P = 0.000). CONCLUSION: Ultrasound-guided BSCPB with ropivacaine 0.5% can enhance the quality of recovery, postoperative analgesia, and reduce the incidence of PONV in uremia patients with SHPT following parathyroidectomy. TRIAL REGISTRATION: ChiCTR1900027185 . (Prospective registered). Initial registration date was 04/11/2019.

Effects of lidocaine, dexmedetomidine, and their combination infusion on postoperative nausea and vomiting following laparoscopic hysterectomy: a randomized controlled trial.

BACKGROUND: A few studies have reported that administration of lidocaine and dexmedetomidine relieves the incidence of postoperative nausea and vomiting (PONV). We explored whether combined infusion of lidocaine plus dexmedetomidine had lower occurrence of PONV undergoing laparoscopic hysterectomy with general anesthesia. METHODS: A total of 248 women undergoing elective laparoscopic hysterectomy were allocated into the following four groups: the control group (group C, n = 62) received an equal volume of saline, the lidocaine group (group L, n = 62) received intravenous lidocaine (bolus infusion of 1.5 mg/kg over 10 min, 1.5 mg/kg/h continuous infusion), the dexmedetomidine group (group D, n = 62) received dexmedetomidine administration (bolus infusion of 0.5 µg/kg over 10 min, 0.4 µg/kg/h continuous infusion), and the lidocaine plus dexmedetomidine group (group LD, n = 62) received combination of lidocaine (bolus infusion of 1.5 mg/kg over 10 min, 1.5 mg/kg/h continuous infusion) and dexmedetomidine administration (bolus infusion of 0.5 µg/kg over 10 min, 0.4 µg/kg/h continuous infusion). The primary outcome was the incidence of nausea, vomiting, and PONV during the first 48 h after surgery. The secondary outcomes included the incidence of total 24 h PONV after surgery, intraoperative remifentanil requirement, postoperative pain visual analogue scale (VAS) scores and fentanyl consumption, the incidence of bradycardia, agitation, shivering, and mouth dry during post-anesthesia care unit (PACU) stay period. RESULTS: The occurrence of nausea and PONV in group LD (5.0 and 8.3%) at 0-2 h after operation was lower than group C (21.7 and 28.3%) (P < 0.05). There was no statistically significant difference with respect to occurrence of nausea and PONV in groups L (13.3 and 20.0%) and D (8.3 and 13.3%) at 0-2 h after operation compared to group C (21.7 and 28.3%). The incidence of nausea, vomiting, and PONV at 2-24 and 24-48 h after surgery in all four groups was not statistically significant. The incidence of total 24 h PONV in group LD (33.3%) was significantly decreased compared to group C (60.0%) (P < 0.05). The cumulative consumption of fentanyl at 6 and 12 h after surgery was significantly reduced in group LD compared to other three groups (P < 0.05). The pain VAS scores were significantly decreased at 2, 6, and 12 h after operation in group LD compared to other three groups (P < 0.05). Remifentanil dose in the intraoperative period was significantly lower in groups LD and D compared with groups C and L (P < 0.05). The number of mouth dry, bradycardia, and over sedation during the PACU stay period was markedly increased in group LD (28.3, 30.0, and 35.0%, respectively) compared with groups C (1.7, 1.7, and 3.3%, respectively) and L (3.3, 5.0, and 6.7%, respectively) (P < 0.05). CONCLUSIONS: Lidocaine combined with dexmedetomidine infusion markedly decreased the occurrence of nausea and PONV at 0-2 h as well as the total 24 h PONV. However, it significantly increased the incidence of mouth dry, bradycardia, and over sedation during the PACU stay period after laparoscopic hysterectomy with general anesthesia. TRIAL REGISTRATION: ClinicalTrials.gov ( NCT03809923 ), registered on January 18, 2019.

Effects of intravenous lidocaine, dexmedetomidine, and their combination on IL-1, IL-6 and TNF-α in patients undergoing laparoscopic hysterectomy: a prospective, randomized controlled trial.

BACKGROUND: Surgical-related inflammatory responses have negative effects on postoperative recovery. Intravenous (IV) lidocaine and dexmedetomidine inhibits the inflammatory response. We investigated whether the co-administration of lidocaine and dexmedetomidine could further alleviate inflammatory responses compared with lidocaine or dexmedetomidine alone during laparoscopic hysterectomy. METHODS: A total of 160 patients were randomly allocated into four groups following laparoscopic hysterectomy: the control group (group C) received normal saline, the lidocaine group (group L) received lidocaine (bolus infusion of 1.5 mg/kg over 10 min, 1.5 mg/kg/h continuous infusion), the dexmedetomidine group (group D) received dexmedetomidine (bolus infusion of 0.5 µg/kg over 10 min, 0.4 µg/kg/h continuous infusion), and the lidocaine plus dexmedetomidine group (group LD) received a combination of lidocaine (bolus infusion of 1.5 mg/kg over 10 min, 1.5 mg/kg/h continuous infusion) and dexmedetomidine (bolus infusion of 0.5 µg/kg over 10 min, 0.4 µg/kg/h continuous infusion). The levels of plasma interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) at different time points were the primary outcomes. Secondary outcomes included hemodynamic variables, postoperative visual analogue scale (VAS) scores, time to first flatus, and incidence of nausea and vomiting after surgery. RESULTS: The levels of plasma IL-1, IL-6, and TNF-α were lower in groups D and LD than in group C and were lowest in group LD at the end of the procedure and 2 h after the operation (P < 0.05). The VAS scores were decreased in groups D and LD compared with group C (P < 0.05). The heart rate (HR) was decreased at the end of the procedure and 2 h after the operation in groups D and LD compared to groups C and L (P < 0.001). The mean blood pressure (MBP) was lower at 2 h after the operation in groups L, D, and LD than in group C (P < 0.001). There was a lower incidence of postoperative nausea and vomiting (PONV) in group LD than in group C (P < 0.05). CONCLUSIONS: The combination of lidocaine and dexmedetomidine significantly alleviated the inflammatory responses, decreased postoperative pain, and led to fewer PONV in patients undergoing laparoscopic hysterectomy. TRIAL REGISTRATION: ClinicalTrials.gov ( NCT03276533 ), registered on August 23, 2017.

Cd Adsorption by Iron-Organic Associations: Implications for Cd Mobility and Fate in Natural and Contaminated Environments.

The mobility and fate of Cd in soil are mainly controlled by active substances such as iron minerals and organic matter. Iron minerals and organic matter often coexist in the form of iron-organic associations (IOA), which have large specific surface areas and many functional groups, potentially affecting Cd adsorption. However, little is known about Cd adsorption by IOA. This study investigated Cd adsorption by the synthetic IOA under different conditions. The results indicate Cd adsorption increased with the increasing amount of IOA, while the adsorption efficiency decreased gradually. pH significantly affects Cd adsorption, because the Cd speciation and the surface charge of IOA changed under different pH conditions. Under alkaline condition, part of Cd would form hydroxide precipitate, facilitating Cd adsorption by IOA. The composition of organic matter in IOA didn't significantly affect Cd adsorption.

Simultaneous Sensitive Determination of Selenium, Silver, Antimony, Lead, and Bismuth in Microsamples Based on Liquid Spray Dielectric Barrier Discharge Plasma-Induced Vapor Generation.

A highly efficient liquid spray dielectric barrier discharge (LSDBD) plasma-induced vapor generation technique is developed for the simultaneous determination of selenium, silver, antimony, lead, and bismuth in liquid microsamples (20 µL) by inductively coupled plasma mass spectrometry (ICP-MS). It is demonstrated that the dissolved Se, Ag, Sb, Pb, and Bi ions in solution samples are readily and simultaneously converted to volatile species efficiently by LSDBD plasma-induced chemical processes under similar conditions. It eliminates the use of unstable and expensive reducing reagents, and only formic acid is required in the proposed LSDBD chemical vapor generation technique. It is also worth noting that this is the first report of using plasma-induced chemical processes for the vapor generation of Ag and Bi. The simultaneous sensitive determination of Se, Ag, Sb, Pb, and Bi is realized with a sample volume of only 20 µL and the sample throughput could be as high as 180 samples h-1. The limit of detection (LOD) for simultaneous determination of Se, Ag, Sb, Pb, and Bi is 10 ng L-1 (200 fg), 2 ng L-1 (40 fg), 5 ng L-1 (100 fg), 4 ng L-1 (80 fg), and 3 ng L-1 (60 fg), respectively. The precision of Se, Ag, Sb, Pb, and Bi in the present method is evaluated to be better than 4%. The utility of the proposed technique is demonstrated by the analysis of ultratrace Se, Ag, Sb, Pb, and Bi in archaea cells and single conodont samples.

Determination of Cl, Br, and I in Geological Materials by Sector Field Inductively Coupled Plasma Mass Spectrometry.

In this study, a simple and effective method for the simultaneous analysis of Cl, Br, and I in geological materials based on NH4HF2 digestion in open vessels (Savillex Teflon vials) is proposed. It is very interesting to note that Cl, Br, and I are not lost during NH4HF2 digestion at temperatures of 200-240 °C for 0.5-12 h in open vessels. This should be related to the alkaline atmosphere environment caused by the NH3 produced during NH4HF2 digestion, which suppresses the volatilization loss of Cl, Br, and I. A 100 mg sample of geological materials can be completely digested by using 400 mg of NH4HF2 at 220 °C for 2 h in Savillex Teflon vials. The use of new Savillex Teflon vials significantly reduced the procedural blanks of halogens compared with the old Savillex Teflon vials. The developed method was successfully applied to the simultaneous determination of Cl, Br, and I in a series of international geological reference materials. Most of the results were found to be in reasonable agreement with values reported in the literature. This simple, rapid, effective, and economical analytical method will significantly promote the development of halogen geochemistry.

Highly Sensitive Determination of Arsenic and Antimony Based on an Interrupted Gas Flow Atmospheric Pressure Glow Discharge Excitation Source.

A novel interrupted gas flow (IF) technique has been proposed for highly sensitive determination of ultratrace levels of arsenic and antimony in water samples by atmospheric pressure glow discharge (APGD) excitation source coupled with HCl-KBH4 hydride generation (HG). It is demonstrated that the gas flow interruption technique provides a dramatic and reproducible enhancement of emission signals of 1-2 orders of magnitude for As and Sb over conventional continuous gas flow (CF) in APGD. The enhanced analyte emission sensitivities in IF-APGD were investigated from the viewpoint of changes in plasma excitation temperature and analyte density. With eight As lines as the thermometric probe, no measurable change in excitation temperature was found, suggesting that the enhancement is caused by an increase in analyte number density in the plasma immediately following the gas flow interruption. Furthermore, the enhancement factor was found to increase with the time interval in between the gas interruption, supporting an analyte adsorption (or trap)-release mechanism hypothesis. Under optimized conditions, the detection limits (DLs) of IF-APGD mode for As and Sb were calculated to be 0.02 and 0.003 µg L-1, which are, respectively, about 27- and 120-fold improved compared to CF-APGD mode. The linearity of calibration for both As and Sb reached R2 > 0.999 in the 0.1-5 µg L-1 range. The accuracy of the proposed method was validated by the determination of certified reference materials (CRMs), and the results agreed well with the certified values.

Effects of intravenous infusion of lidocaine and dexmedetomidine on inhibiting cough during the tracheal extubation period after thyroid surgery.

BACKGROUND: Intravenous lidocaine and dexmedetomidine treatments have been proposed as methods for inhibiting cough. We compared the efficacy of intravenous lidocaine and dexmedetomidine treatments on inhibiting cough during the tracheal extubation period after thyroid surgery. METHODS: One hundred eighty patients undergoing thyroid surgeries were randomly allocated to the LIDO group (received lidocaine 1.5 mg/kg loading, 1.5 mg/kg/h infusion), the DEX group (received dexmedetomidine 0.5 µg/kg loading, 0.4 µg/kg/h infusion) and the CON group (received saline), with 60 cases in each group. The primary outcomes of cough were recorded. Secondary outcomes included hemodynamic variables, awareness time, volume of drainage, the postoperative visual analogue scale and adverse effects were recorded. RESULTS: The incidence of cough were significantly lower in the LIDO group (28.3%) and the DEX group (31.7%) than that in the CON group (66.7%) (P = 0.000). Additionally, both moderate and severe cough were significantly lower in the LIDO group (13.3%) and the DEX group (13.4%) than these in the CON group (43.4%) (P < 0.05). Compared with the two treatment groups, both mean arterial blood pressure and heart rate were significantly increased in the CON group during tracheal extubation (P < 0.05). Compared with the CON group, the volume of drainage was significantly reduced in the two treatment groups within 48 h after surgery (P < 0.05). compared with the CON group, the postoperative visual analogue scale was significantly lower in groups LIDO and DEX after surgery(P < 0.05). Compared with the LIDO group and the CON group, the time to awareness was longer in the DEX group (P < 0.05). In the DEX group, bradycardia was noted in 35 patients, while no bradycardia was noted in LIDO group and CON group. CONCLUSION: Compared with intravenous infusions of normal saline, both lidocaine and dexmedetomidine had equal effectiveness in attenuating cough and hemodynamic changes during the tracheal extubation period after thyroid surgery, and both of these treatments were able to reduce the volume of postoperative bleeding and provide better analgesic effect after surgery. But intravenous infusions of dexmedetomidine resulted in bradycardia and delayed the time to awareness when compared with lidocaine and normal saline. TRIAL REGISTRATION: ChiCTR1800017482 . (Prospective registered). Initial registration date was 01/08/2018.

An amino-functionalized ordered mesoporous polymer as a fiber coating for solid phase microextraction of phenols prior to GC-MS analysis.

An amino-functionalized ordered mesoporous polymer (OMP-NH2) was synthesized and applied as a fiber coating for solid phase microextraction of polar phenols from environmental samples. The fiber coating was prepared by loading the OMP-NH2 powder onto a stainless steel wire through silicone gel. Combined with GC-MS, the fibers were employed to quantify trace of phenols in water through headspace-SPME. The characterization showed the OMP-NH2 to have a large specific surface area (420 m2 g-1) and good thermal stability (>400 °C). Due to its mesoporous structure and favorable interactions via hydrogen bonding and π stacking interactions with phenols, the sorbent represents a promising candidate for the separation and enrichment of polar phenols. Extraction conditions, such as temperature, extraction time, salt concentration, pH value and desorption time, were fully optimized. Under the optimized conditions, the coating exhibits an enrichment effect that is ~2-10 times better than that of a commercial polyacrylate coating. Figures of merit include (a) low limits of detection (0.05-0.16 ng L-1), (b) wide linear ranges (0.2-10,000 ng L-1), and (c) high enrichment factors (510-2272). The relative standard deviations for one fiber and fiber-to-fiber were in the range of 4.0-6.1% and 4.6-7.4%, respectively. The method was applied to the determination of phenols in water samples and gave satisfactory recoveries between 85.4 and 112.2%. Graphical abstract An amino-functionalized ordered mesoporous polymer (OMP-NH2) was synthesized by a solventless method and applied as headspace solid phase microextraction (HS-SPME) fiber coating for the extraction of polar phenols from the environmental samples.

Water Vapor-Assisted "Universal" Nonmatrix-Matched Analytical Method for the in Situ U-Pb Dating of Zircon, Monazite, Titanite, and Xenotime by Laser Ablation-Inductively Coupled Plasma Mass Spectrometry.

The U-Pb geochronologic analysis of accessory minerals has played an important role in Earth and solar system science in constraining the ages of a wide variety of rocks and minerals. Laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) is one of the most popular techniques for U-Pb geochronologic analysis. Currently, the significant matrix effects observed between different accessory minerals and the lack of high-quality standards for many minerals of interest are the major limitations of its geochronological applications. In this study, we investigated the effects of the addition of oxygen, nitrogen, and water vapor before and after the ablation cell on the accuracy of the U-Pb dating of different minerals (e.g., zircon, monazite, titanite, and xenotime) by LA-ICP-MS. We found that the addition of water vapor, unlike that of oxygen and nitrogen, before the ablation cell can significantly suppress the matrix effects on U-Pb dating. The deviations of the measured 206Pb/238U ratios in these accessory minerals were significantly reduced from 10 to 24% to less than 1-2% when using NIST 610 glass as an external standard. This can be attributed to the suppression of elemental fractionation in both the laser ablation and ICP ionization processes by the presence of water vapor. The developed water vapor-assisted LA-ICPMS U-Pb dating method has been successfully applied to the analysis of zircon, monazite, xenotime, and titanite with NIST 610 glass as a reference material in both the 193 nm excimer laser and 213 nm Nd:YAG laser ablation systems.

Rapid Identification of Unknown Organic Iodine in Small-Volume Complex Biological Samples Based on Nanospray Mass Spectrometry Coupled with in-Tube Solid Phase Microextraction.

A new method for rapid screening of unknown organic iodine (OI) in small-volume complex biological samples was developed using in-tube solid phase microextraction (SPME) nanospray mass spectrometry (MS). The method proposed a new identification scheme for OI based on nanospray high-resolution mass spectrometry (HR-MS). The mass ranges of OI ions were confirmed using the t-MS2 scan mode first; then, the possible precursor ions of OI were selected and identified orderly in full MS/ddMS2 and t-MS2 scan modes. Besides, in-tube SPME was used for the pretreatment of small-volume biological samples, and it was the first time in-tube SPME combined with nanospray MS for OI identification. The whole analysis procedure took only 8 min and consumed 50 µL per sample. Using the new method, six kinds of OI added to urine and an unknown OI C12H23O11I in human milk were successfully identified. Moreover, the proposed identification scheme is also suitable for other ambient mass spectrometry (AMS) to determine unknown compounds with characteristic fragment ions.

Generation of Volatile Cadmium and Zinc Species Based on Solution Anode Glow Discharge Induced Plasma Electrochemical Processes.

In this study, a novel high efficiency vapor generation strategy was proposed on the basis of solution anode glow discharge for the determination of Cd and Zn by atomic fluorescence spectrometry. In this approach, a glow discharge microplasma was acted as a gaseous cathode to initiate the plasma electrochemical vapor generation of Cd and Zn. Cadmium/zinc ions could be converted into molecular species efficiently at the plasma-liquid interface from a supporting electrolyte (HCl, pH = 3.2). It was found that the overall efficiency of the plasma electrochemical vapor generation (PEVG) system was much higher than the conventional electrochemical hydride generation (EcHG) and HCl-KBH4 system. With no requirement for other reducing reagents, this new approach enabled us to detect Cd and Zn with detection limits as low as 0.003 µg L-1 for Cd and 0.3 µg L-1 for Zn. Good repeatability (relative standard deviation (RSD), n = 5) was 2.4% for Cd (0.1 µg L-1) and 1.7% for Zn (10 µg L-1) standard. The accuracy of the proposed method was successfully validated through analysis of cadmium in reference material of stream sediment (GBW07311), soil (GBW07401), rice (GBW10045), and zinc in a simulated water sample (GSB 07-1184-2000). Replacing a metal electrode with a plasma offers the advantage of eliminating potential interactions between the species in liquid and the electrode, which solves the issues associated with electrode encountered in conventional EcHG. The ability to initiate electrochemical vapor generation reactions at the plasma-liquid interface opens a new approach for chemical vapor generation based on interactions between plasma gas-phase electrons and solutions.

Liquid Spray Dielectric Barrier Discharge Induced Plasma-Chemical Vapor Generation for the Determination of Lead by ICPMS.

In the present study, a novel and sensitive liquid spray dielectric barrier discharge induced plasma-chemical vapor generation technique (LSDBD-CVG) is developed for the determination of lead concentration by inductively coupled plasma mass spectrometry (ICPMS). The dissolved Pb2+ is readily converted to volatile species by LSDBD plasma induced chemical processes in the presence of 5% (v/v) formic acid in a supporting electrolyte (HCl, 0.01 mol L-1). In this LSDBD approach, the sample solution is converted to aerosol and simultaneously mixed with the DBD plasma generated at the nozzle of a pneumatic nebulizer, which greatly facilitates Pb vapor generation because of the enhanced interaction of sprayed analytes and the plasma. Optimal conditions for LSDBD-CVG were identified, and the interference effects from other metal ions were assessed. Under optimized conditions, the detection limit of Pb was found to be 0.003 µg L-1. The repeatability, expressed as the relative standard deviation (RSD) of the peak height, for the five replicate measurements of 0.03 and 1 µg L-1 lead standard, were 2.1% and 1.7%, respectively. Compared with other vapor generation methods, this new LSDBD-CVG offers several advantages including no requirement of unstable reagents, fast response, and easy coupling with flow injection, along with high tolerance for coexisting ions. The accuracy of the proposed method is demonstrated by successful analysis of Pb in reference material of stream sediment (GBW07311), soil (GBW07403), basalt (BCR-2), and simulated water sample (GBW08601). The proposed LSDBD-CVG extends the scope of elements accessible by plasma-CVG and provides an alternative efficient green approach for the vapor generation of Pb.

Battery-Operated Atomic Emission Analyzer for Waterborne Arsenic Based on Atmospheric Pressure Glow Discharge Excitation Source.

In this paper, a sensitive atomic emission spectrometer (AES) based on a new low power and low argon consumption (<8 W, 100 mL min-1) miniature direct current (dc) atmospheric pressure glow discharge (APGD) plasma (3 mm × 5 mm) excitation source was developed for the determination of arsenic in water samples. In this method, arsenic in water was reduced to AsH3 by hydride generation (HG), which was then transported to the APGD source for excitation and detected by a compact CCD (charge-coupled device) microspectrometer. Different parameters affecting the APGD and the hydride generation reactions were investigated. The detection limit for arsenic with the proposed APGD-AES was 0.25 µg L-1, and the calibration curves were found to be linear up to 3 orders of magnitude. The proposed method was successfully applied to the determination of certified reference material (GBW08605), tap water, pond water, groundwater, and hot spring samples. Measurements from the APGD analyzer showed good agreement with the certified value/values obtained with well-established hydride generation atomic fluorescence spectrometry (HG-AFS). These results suggest that the developed robust, cost-effective, and fast analyzer can be used for field based arsenic determination and may provide an important tool for arsenic contamination and remediation programs.