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Plant diseases reduce crop yield and quality, hampering the development of agriculture. Fungicides, which restrict chemical synthesis in fungi, are the strongest controls for plant diseases. However, the harmful effects on the environment due to continued and uncontrolled utilization of fungicides have become a major challenge in recent years. Plant-sourced fungicides are a class of plant antibacterial substances or compounds that induce plant defenses. They can kill or inhibit the growth of target pathogens efficiently with no or low toxicity, they degrade readily, and do not prompt development of resistance, which has led to their widespread use. In this study, the growth inhibition effect of 24 plant-sourced ethanol extracts on rice sprigs was studied. Ethanol extract of gallnuts and cloves inhibited the growth of bacteria by up to 100%. Indoor toxicity measurement results showed that the gallnut and glove constituents inhibition reached 39.23 μg/mL and 18.82 μg/mL, respectively. Extract treated rice sprigs were dry and wrinkled. Gallnut caused intracellular swelling and breakage of mitochondria, disintegration of nuclei, aggregation of protoplasts, and complete degradation of organelles in hyphae and aggregation of cellular contents. Protection of Rhizoctonia solani viability reached 46.8% for gallnut and 37.88% for clove in water emulsions of 1000 μg/mL gallnut and clove in the presence of 0.1% Tween 80. The protection by gallnut was significantly stronger than that of clove. The data could inform the choice of plant-sourced fungicides for the comprehensive treatment of rice sprig disease. The studied extract effectively protected rice sprigs and could be a suitable alternative to commercially available chemical fungicides. Further optimized field trials are needed to effectively sterilize rice paddies.

Treatment of 1,2-C6H4(SiH3)(SiH3) (1) with Pt(dcpe)(PEt3)2 (dcpe = Cy2PCH2CH2PCy2) in dry toluene at room temperature in the ratio of 1:1 leads to the complex {1,2-C6H4(SiH2)(SiH2)}PtII(dcpe) (2), which can react with proton organic reagent bearing hydroxy group with low steric hindrance to form a tetra-alkoxy substituted silyl platinum(II) compound (3). The structures of complexes (2) and (3) were unambiguously determined by multinuclear NMR spectroscopic studies and single crystal X-ray analysis.

A hollow cathode configuration was designed for a Grimm-type glow discharge atomic emission spectrometer (GD-AES). The operating conditions including the hollow cathode dimension, applied pulsed voltage and argon pressure, were optimized. The 10-μs pulses at 1.8 kV in a 3-torr discharge worked best. A pulsed hollow cathode Grimm discharge (HCG) offers several advantages: efficient excitation and ionization; high sensitivity; temporal spectral resolution; and rapid sample interchange. The capability of this source for the determination of elemental composition in metals, alloys and in solution residues is investigated. Samples used in this study included copper and steel standards.

The already established technique of pulsed glow discharge spectroscopy is extended in these studies to the application of a second pulse applied at a variable delay after a first pulse. The net discharge then consists of a series of double pulses in which each second pulse in the series enhances the emission intensity of the analyte atoms produced by the first pulse. A copper hollow cathode is used to show high emission enhancement for atom and ion lines of the sputtered species and the neon discharge gas species. The technique shows promise for further study by both atomic emission and mass spectrometry.

The development of microsecond pulsed glow discharge atomic emission spectrometry (GD-AES) for quantitative depth profile analysis is described. The quantification method, which is based on sputtering rates, has been previously applied to depth analysis employing a dc glow discharge source. Optimal conditions of the glow discharge source, including voltage, pressure, pulse width and pulse frequency, are utilized in order to give the best depth resolution. Pulsed operation of the glow discharge affords the advantages of two additional parameters, pulse width and pulse frequency, which allow better control over the amount of sample being removed via cathodic sputtering. This allows thin layer samples to be analyzed that are very difficult using the dc source. Under the optimized parameters, thin coatings of varying depths of Cu deposited on steel were quantified. The quantitative method predicted Cu deposition depths in accord with the nominal depths.

A Grimm-type glow discharge ion source has been constructed for a time-of-flight mass spectrometer (TOF-MS). This source was operated in the microsecond-pulsed mode. Special features of pulsed Grimm GD-TOF-MS are described, including resolving power, stability, sensitivity and the temporal separation of discharge gas species and analyte ions. The analytical characteristics of a pulsed Grimm GD-TOF-MS system were also evaluated. These preliminary studies demonstrate the potential of this technique for the elemental analysis for solids.

A high voltage, microsecond regime, pulsed glow discharge has been applied to a standard Grimm type source on a LECO SA-2000 multichannel optical spectrometer. The spectrometer system has been equipped with fast time-resolved electronics in order to study the temporal response of the elemental emission lines. The aim of the research was to investigate possible gains in signal-to-background ratio (S/B) and detection limits compared to a conventional direct current (dc) mode of operation. It was found that the high instantaneous pulse power in itself gives approximately a factor 2 increase in S/B. By utilising time-resolved detection, gains in the range 5–10 are achieved. For nitrogen, it was found that the background from leakage of air could be reduced to approximately 1/3 compared with the dc mode. Another interesting observation was that certain nearly non-conducting materials, which cannot be run in dc mode, could be run in the microsecond pulsed mode.

Investigations have been performed using microsecond pulsed glow discharge atomic emission spectrometry (GD-AES) to determine the effect of the glow discharge parameters, including applied pulse voltage, pulse width, pulse frequency and gas pressure, on the resolution of depth profiling. The results indicate that a concave crater profile is obtained for low voltage, whereas the curvature is convex for high voltage. The criteria of a flat crater bottom and good depth resolution are fulfilled only with a limited range of voltages at each operating pressure. The results also imply that the pulse frequency and pulse width have little effect on the resolution of depth profiling; thus a wide dynamic range of layers from several nanometers to tens of micrometers can be analyzed by increasing or decreasing the pulse frequency and width. Under the optimized parameters, a thin coating of Cu (50 nm) on steel, an electroplated steel and a computer hard-disk with multiple thin layers were analyzed.

A high voltage, microsecond regime pulse dc glow discharge was applied to a standard Grimm source on a modified LECO SA-2000 direct reader spectrometer and to a duplicate Grimm source coupled to a scanning monochromator. The effects of experimental conditions, including pulse voltage, pulse frequency, pulse width and Ar pressure, on Cu atomic and ionic emission intensities were examined and compared with continuous discharge results. The pulsed Grimm source has a higher sputtering rate, greater signal intensity and lower detection limits. The pulsed signal for atomic lines shows a different temporal response from ionic lines. Pulsed Grimm GD-AES also offers control features advantageous in the measurement of thin surface layers.

A thermospray nebulizer was used as a sample introduction device for microwave plasma torch (MPT) atomic emission spectrometry (AES). Experimental parameters, including the power supplied to the MPT, the flow rates of support and carrier gases, the observation height, the sample uptake rate, the thermospray working temperature, the temperature of the aerosol spray chamber and cooling water were optimized. Under optimum conditions, the relative standard deviation (RSD) of 10 measurements for 21 elements is in the range 0.3–2.0%. The detection limits were improved in comparison with the ultrasonic nebulizer as sample introduction technique for MPT–AES. The inclusion of 20% methanol into the MPT showed there is no effect on the stability of MPT discharge. The technique can thus be held to have the potential for interface to reverse-phase HPLC systems.

A transient data acquisition system for flow injection analysis (FIA), high performance liquid chromatography (HPLC), and electrothermal vaporization (ETV) combined with ICP-AES multi-element instrumentation was developed and successfully applied to the analysis of different types of samples, including human serum, human hair and tea, for simultaneous multi-element determinations. The accuracy of the method was verified with hair reference material. Good agreement between the experimental results and certified values, and also satisfactory recoveries from standard additions, were achleved.

Palladium salts can be used as a coprecipitation carrier for the preconcentration of trace elements from natural water prior to their measurement by atomic spectrometry (AAS). The palladium is subsequently reduced by the introduction of hydrogen gas into the sample solution. The procedure is applied to the determination of Cu, Pb and Cd in seawater (enrichment factor 50) and synthetic water samples. Operating conditions have been optimized for the analysis of real samples. With the technique established an enrichment factor (500 fold) is feasible in synthetic samples. The recoveries of Cu, Cd and Pb from seawater are 95, 103 and 100%, respectively. This simple and rapid method can be applied in a wide pH-range and with complex matrices.

Over 100 hair samples were collected from the Xiamen area of south China, including 72 healthy people and 34 cancer patients, for the study of distinguishing cancer patients from others; another 64 hair samples were collected from patients with liver, stomach, lung, and miscellaneous cancers and were used for the discrimination analysis of different types of cancers, The samples were analyzed with ICP-AES for the simultaneous determination of several elements and with GFAAS for Se content after wet digestion. The average values of the element concentrations in the hair samples are presented. The results obtained were then analyzed with principal component analysis and partial least-squares methods, to distinguish cancer patients from others, and with an orthaganolization recurrence method to discriminate different types of cancers. The cancer patients could be completely distinguished from healthy people; while the misdiscrimination rates for the analysis of liver, stomach, and lung cancers are 15.8, 14.3, and 19.0%, respectively.

The determination of metal concentrations in fish with ICP-AES and FAAS was performed. Based on the metal concentrations found in fish collected from four regions of south China, principal component analysis was applied to a bioindicator study. The relationships between metal concentrations in fish tissues and those in seawater were studied by a simulated experiment. Using these relationships, the accumulation factors were determined, and the mean concentrations of Zn, Cd, Cu, and Pb in the coastal seawater of Min Jiang estuary, Dong Shan island, Me Zhuong island, and Hai Tan island were estimated.

The application of microsecond pulsed Grimm glow discharge atomic emission spectrometry for depth profiling of thin films is examined. The effects of pulsed conditions including pulse voltage, pulse frequency, pulse width, and Ar pressure on depth profiling performance were characterized for Zn and Cu coatings on steel. Using optimized conditions, linear calibration curves of coating thickness for Zn (6.1-26.9 μm) and Cu (50-500 nm) on steel were achieved. A precision of 2-5% relative standard deviation was determined. An ultrathin coating of Cu (10 nm) on steel was also measured by this technique.

A Grimm-type glow discharge ion source, operated in the microsecond pulsed mode, has been interfaced to a commercial time-of-flight mass spectrometer. Ion transport from the source to the mass spectrometer, an inherent limitation of a Grimm source and mass spectrometer combination, was evaluated. The primary discharge operating conditions found to influence transport efficiency were gas flow rate and source pressure. The configuration of the Grimm-type source also influenced ion transport, including use of a gas-directing sleeve device. The effect of transport efficiency was separated into two components: (1) total ion signal and (2) temporal resolution. The latter is an advantage afforded by use of a pulsed glow discharge source and time-of-flight spectrometer, which allows discrimination against interfering gaseous background ions by appropriate ion sampling time. Shown as an example is the identification of trace magnesium from potential background interference using an optimized source configuration based on this temporal resolution method.

Pulsing the glow discharge offers new experiments and applications with a well-established technique.