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A new version of the direct injection nebulizer (DIN) is used to interface liquid chromatographic (LC) separations with element-selective detection using inductively coupled plasma mass spectrometry (ICP-MS). The DIN injects all of the sample into the ICP and has a dead volume of less than 1 microliter. Charged species of arsenic and tin are separated as ion pairs on a micro-scale (1 mm i.d.), packed, reversed-phase column. Detection limits are 0.2-0.6 pg for arsenic and 8-10 pg for tin. For methanol + water eluents, the signal is highest at 25% methanol and stays within 25% of this maximum as the methanol fraction is varied from 20 to 80%. Compared with LC-ICP-MS with conventional nebulizers, the absolute detection limits and chromatographic resolution are substantially superior, and the dependence of analyte signal on solvent composition is somewhat less severe with the DIN.
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PMID:Elemental speciation by liquid chromatography-inductively coupled plasma mass spectrometry with direct injection nebulization. 158 Apr 4

Inductively coupled plasma mass spectrometry (ICP/MS) is utilized as a detector for several organotin species separated by high-performance liquid chromatography. Detection limits obtained by ICP/MS are 3 orders of magnitude lower than those obtained with inductively coupled plasma atomic emission spectrometry (ICP/AES) detection under the same chromatographic conditions. Chromatographic detection limits are higher than conventional solution nebulization for the same compound by a factor of 20. Ion-exchange chromatography yields linear response over 3 orders of magnitude, while ion pair chromatography gives a linear response of only 2 orders of magnitude as a result of poor resolution. The relative standard deviation for the injection of 20 ng of tin compounds is less than 10%.
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PMID:Inductively coupled plasma mass spectrometry and atomic emission spectrometry coupled to high-performance liquid chromatography for speciation and detection of organotin compounds. 270 97

Various canned foods were digested sequentially with HNO3 and HCl, diluted to 100 mL, and filtered, and then tin was determined by inductively coupled plasma atomic emission spectrometry (ICP/AES). Samples of canned Satsuma mandarin, peach, apricot, pineapple, apple juice, mushroom, asparagus, evaporated milk, short-necked clam, spinach, whole tomato, meat, and salmon were evaluated. Sample preparations did not require time-consuming dilutions, because ICP/AES has wide dynamic range. The standard addition method was used to determine tin concentration. Accuracy of the method was tested by analyzing analytical standards containing tin at 2 levels (50 and 250 micrograms/g). The amounts of tin found for the 50 and 250 micrograms/g levels were 50.5 and 256 micrograms/g, respectively, and the repeatability coefficients of variation were 4.0 and 3.8%, respectively. Recovery of tin from 13 canned foods spiked at 2 levels (50 and 250 micrograms/g) ranged from 93.9 to 109.4%, with a mean of 99.2%. The quantitation limit for tin standard solution was about 0.5 microgram/g.
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PMID:Inductively coupled plasma atomic emission spectrometric determination of tin in canned food. 828 77

The use of inductively coupled plasma source mass spectrometry (ICP-MS) for multi-element analysis has led to the observation, in two separate studies, of increased blood tin in Alzheimer's disease (AD). We have therefore applied the technique of ICP-MS to hippocampal tissues obtained post-mortem from patients with AD and from controls. There was no significant difference in tin concentrations in AD. There were increased concentrations of aluminum and silicon, and reduced concentrations of zinc and selenium. It is postulated that displacement of hippocampal zinc by heavy metals may be important in producing clinical memory disturbance. However, analysis of the CA1 region, rather than of the dentate gyrus, would have been preferable.
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PMID:Hippocampal tin, aluminum and zinc in Alzheimer's disease. 840 Jul 61

Inductively coupled plasma-mass spectrometry (ICP-MS) has been used to determine concentrations of total tin in samples of apples, pears and kiwi fruit, following acid digestion. It was found that the background levels of tin in these fruits were normally below 0.06 mg/kg, which was equivalent to the target reporting limit for cyhexatin for this work of 0.2 mg/kg. The procedure was used to screen a total of 72 retail samples. Three apple samples contained tin at concentrations greater than 0.06 mg/kg. These three samples were re-analysed by a second confirmatory method using gas chromatography-mass spectrometry (GC-MS) as the determinative step. Results obtained by this method demonstrated that in fact, none of the samples contained cyhexatin residues at or above a reporting limit of 0.1 mg/kg. The use of ICP-MS as a preliminary screen substantially reduced the number of samples requiring analysis by GC-MS, thus reducing the cost of the survey (in terms of staff hours) by approximately 30%. The screening method could potentially be applied to other organometallic pesticide residues.
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PMID:The analysis of cyhexatin residues in apples, pears and kiwi fruit using inductively coupled plasma mass spectrometry as an initial screen for total tin, with confirmation by gas chromatography-mass spectrometry. 966 87

Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine 18 trace elements (Ba, Be, Bi, Cd, Co, Cs, Cu, La, Li, Mn, Mo, Pb, Rb, Sb, Sn, Sr, Tl, and Zn) in 55 human milk samples from 46 healthy mothers collected during lactation periods extending to 293 days after birth. Se was quantified by hydride generation atomic absorption spectrometry (HG-AAS). To test the accuracy and the precision of the analytical procedure, milk powder reference materials (BCR 063 and BCR 150) were analyzed. The results obtained by ICP-MS and HG-AAS showed good agreement with the certified values. Whenever available, trace element concentrations determined in the human milk samples were compared to reliable literature data. The concentrations of Be (< 0.05 to 0.9 microgram/kg), Bi (< 0.09 to 2.0 micrograms/kg), Cs (1.7 to 7.7 micrograms/kg), La (< 0.05 to 3.7 micrograms/kg), Rb (440 to 1,620 micrograms/kg), and Tl (< 0.08 to 0.5 microgram/kg) are the first to be reported for human milk. The concentrations of the essential trace elements Cu (p < 0.005), Mn (p < 0.05), Mo (p < 0.0005), Se (p < 0.001), and Zn (p < 0.0005) significantly decreased and the concentrations of cobalt significantly increased (p < 0.005) in human milk during the course of lactation. All concentrations for the essential trace element tin in the human milk samples were below the method detection limit of 0.3 microgram/kg. Among the not essential and toxic elements-with the exception of Ba, Pb, and Tl-the trend toward lower concentrations with continuing lactation is much less pronounced than for the essential trace elements. With the exception of Se, the daily intakes of essential trace elements of fully breast-fed infants are considerably lower than dietary recommendations.
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PMID:Changes in the concentrations of trace elements in human milk during lactation. 985 29

The coupling of an electrothermal vaporization (ETV) apparatus to an inductively coupled plasma time-of-flight mass spectrometer (ICP-TOFMS) is described. The ability of the ICP-TOFMS to produce complete elemental mass spectra at high repetition rates is experimentally demonstrated. A signal-averaging data acquisition board is employed to rapidly record complete elemental spectra throughout the vaporization stage of the ETV temperature cycle; a solution containing 34 elements is analyzed. The reduction of both molecular and atomic isobaric interferences through the temperature program of the furnace is demonstrated. Isobaric overlaps among the isotopes of cadmium, tin, and indium are resolved by exploiting differences in the vaporization characteristics of the elements. Figures of merit for the system are defined with several different data acquisition schemes capable of operating at the high repetition rate of the TOF instrument. With the use of both ion counting and a boxcar averager, the dynamic range is shown to be linear over a range of at least 6 orders of magnitude. A pair of boxcar averagers are used to measure the isotope ratio for silver with a precision of 1.9% RSD, despite a cycle-to-cycle precision of 19% RSD. Detection limits of 10-80 fg are calculated for seven elements, based upon a 10-microL injection.
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PMID:Preliminary investigation of electrothermal vaporization sample introduction for inductively coupled plasma time-of-flight mass spectrometry. 1020 39

This manuscript describes the use of Supercritical-Fluid Chromatography (SFC) with plasma spectrometric detection for the analysis of organometallics. An introduction on the principles and characteristics of Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) is included, along with a discussion about requirements for coupling SFC to plasma detection and the different approaches for interfacing SFC to ICP. The last part of this review paper provides a comprehensive description of SFC-ICP applications for the analysis of organometallics containing iron, silicon, tin, chromium, arsenic, lead, mercury and antimony.
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PMID:Element selective detection for supercritical-fluid chromatography. 1086 66

A simple and reliable extraction method was developed for quantitative determination of both butyl- and phenyltin compounds in sediments by capillary gas chromatography combined with inductively coupled plasma mass spectrometry (GC-ICP-MS). Both types of organotin compounds were extracted quantitatively from sediment by mechanical shaking into tropolone-toluene and HCl-methanol. After phase separation and pH adjustment, these organotins were ethylated with sodium tetraethylborate. The method was evaluated by analyzing PACS-2 and NIES No. 12 sediment certified reference materials. The dibutyltin (DBT; 1.14 +/- 0.02 micrograms g-1) and tributyltin (TBT; 1.01 +/- 0.04 micrograms g-1) values observed in PACS-2 sediment closely matched the certified values (DBT, 1.09 +/- 0.15; TBT, 0.98 +/- 0.13 microgram g-1 as tin). The monobutyltin (MBT) value was higher (0.62 +/- 0.02 microgram g-1) by more than two fold over the reference value (0.3 microgram g-1 as tin). The concentrations of TBT (0.18 +/- 0.04 microgram g-1) and triphenyltin (TPhT; 0.0099 +/- 0.002 microgram g-1) in the NIES No. 12 sediment were also in good agreement with the certified and reference values of TBT (0.19 +/- 0.03 microgram g-1 as compound) and TPhT (0.008 microgram g-1 as compound), respectively. Recoveries of TBT, tripentyltin (TPeT) and TPhT from spiked sediments were satisfactory (TBT, 102 +/- 3.4%; TPrT, 96 +/- 3.4%; TPhT, 99 +/- 8.5%). The detection limits as tin were in the range 0.23-0.48 ng g-1 for a 0.5 g sample size. It is also noteworthy that clean-up of the extract is not necessary because of the superior selectivity of ICP-MS detection. The present method was successfully applied to marine sediment samples.
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PMID:A quantitative extraction method for the determination of trace amounts of both butyl- and phenyltin compounds in sediments by gas chromatography-inductively coupled plasma mass spectrometry. 1107 May 44

Simultaneous ion sampling and sequential detection offered by inductively coupled plasma 'time of flight' mass spectrometry (ICP-TOFMS) provides advantages for the analysis of short transient concentration-variable signals as produced in laser ablation. In order to investigate the capabilities of ICP-TOFMS in combination with an excimer laser ablation system, ablation studies on reference materials and geological samples were carried out. Various ICP-TOFMS parameters were optimized for laser-induced aerosols. Transverse rejection ion pulse was used to extend the dynamic range in concentration. A reduced volume ablation cell was designed and used in order to increase the sample density in the ICP. Results for 63 simultaneously measured isotopes (SRM 610 from NIST) lead to limits of detection in the 1-100 microg/g range for a 80 microm crater diameter (10 Hz, 1.2 mJ pulse energy). The reproducibility of signal ratios was determined to be better than 2% RSD for transient signals using 102 ms integration time. These optimized parameters were then used for the analysis of tin-rich fluid inclusions. Preliminary results of multielement analysis and isotopic ratio determinations on individual fluid inclusions (63 isotopes, 102 ms integration time) demonstrate the capabilities of ICP-TOFMS in combination with laser ablation.
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PMID:Optimization of a laser ablation-inductively coupled plasma "time of flight" mass spectrometry system for short transient signal acquisition. 1122 Aug 28


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