Design of LabVIEW®-based software for the control of sequential injection analysis instrumentation for the determination of morphine

LabVIEW®-based software for the automation of a sequential injection analysis instrument for the determination of morphine is presented. Detection was based on its chemiluminescence reaction with acidic potassium permanganate in the presence of sodium polyphosphate. The calibration function approximated linearity (range 5 × 10-10 to 5 × 10-6 M) with a line of best fit of y=1.05x+8.9164 (R2 =0.9959), where y is the log10 signal (mV) and x is the log10 morphine concentration (M). Precision, as measured by relative standard deviation, was 0.7% for five replicate analyses of morphine standard (5 × 10-8 M). The limit of detection (3σ) was determined as 5 × 10-11 M morphine

Soluble manganese(IV) as a chemiluminescence reagent for the determination of opiate alkaloids, indoles and analytes of forensic Interest

We present the results of our investigations into the use of soluble manganese(IV) as a chemiluminescence reagent, which include a significantly faster method of preparation and a study on the effect of formaldehyde and orthophosphoric acid concentration on signal intensity. Chemiluminescence detection was applied to the determination of 16 analytes, including opiate alkaloids, indoles and analytes of forensic interest, using flow injection analysis methodology. The soluble manganese(IV) reagent was less selective than either acidic potassium permanganate or tris(2,2′-bipyridyl)ruthenium(III) and therefore provided a more universal chemiluminescence detection system for HPLC. A broad spectral distribution with a maximum at 730 ± 5 nm was observed for the reaction between the soluble manganese(IV) and a range of analytes, as well as the background emission from the reaction with the formaldehyde enhancer. This spectral distribution matches that reported for chemiluminescence reactions with acidic potassium permanganate, where a manganese(II) emitting species was elucidated. This provides further evidence that the emission evoked in reactions with soluble manganese(IV) also emanates from a manganese(II) species, and not bimolecular singlet oxygen as suggested by previous authors

Coupled Substitutions of Minor and Trace Elements in Co-Existing Sphalerite and Wurtzite

The nature of couple substitutions of minor and trace element chemistry of expitaxial intergrowths of wurtzite and sphalerite are reported. EPMA and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses display significant differences in the bulk chemistries of the two epitaxial intergrowth samples studied. The sample from the Animas-Chocaya Mine complex of Bolivia is Fe-rich with mean Fe levels of 4.8 wt% for wurztite-2H and 2.3 wt% for the sphalerite component, while the sample from Merelani Hills, Tanzania, is Mn-rich with mean Mn levels in wurztite-4H of 9.1 wt% and for the sphalerite component 7.9 wt% In both samples studied the wurtzite polytype is dominant over sphalerite. LA-ICP-MS line scans across the boundaries between the wurtzite and sphalerite domains within the two samples show significant variation in the trace element chemistries both between and within the two coexisting polytypes. In the Merelani Hills sample the Cu+ + Ga3+ = 2Zn2+ substitution holds across both the wurztite and sphalerite zones, but its levels range from around 1200 ppm of each of Cu and Ga to above 2000 ppm in the sphalerite region. The 2Ag+ + Sn4+ = 3Zn2+ coupled substitution does not occur in the material. In the Animas sample, the Cu+ + Ga3+ = 2Zn2+ substitution does not occur, but the 2(Ag,Cu)+ + Sn4+ = 3Zn2+ substitution holds across the sample despite the obvious growth zoning, although there is considerable variation in the Ag/Cu ratio, with Ag dominant over Cu at the base of the sample and Cu dominant at the top. The levels of 2(Ag,Cu)+ + Sn4+ = 3Zn2+ vary greatly across the sample from around 200 ppm to 8000 ppm Sn, but the higher values occur in the sphalerite bands

Dispersant Effects in the Selective Reaction of Aryl Diazonium Salts with Single-Walled Carbon Nanotubes in Aqueous Solution

Current methods of synthesis for carbon nanotubes (CNTs) usually produce heterogeneous mixtures of different nanotube diameters and thus a mixture of electronic properties. Consequently, many techniques to sort nanotubes according to their electronic type have been devised. One such method involves the chemical reaction of CNTs with aryl diazonium salts. Here we examine the reactions of electric arc produced CNTs (dispersed by a variety of surfactants and polymers in aqueous solution) with 4-bromo-, 4-nitro-, and 4-carboxybenzenediazonium tetrafluoroborate salts in order to find conditions for maximum selectivity. Reactions were monitored through the semiconducting S₂₂ and metallic M₁₁ transitions in the UV–vis–NIR absorbance spectra of the nanotube dispersions. Selectivity was observed to depend heavily on the type of surfactant, the type of diazonium salt and its concentration, the reaction temperature, and the solution pH. Additionally, the surfactant concentration was found to exert a significant influence as the dediazoniation product yields are affected by this parameter. For certain combinations of surfactant and diazonium salt the selectivity is markedly improved, particularly in dispersions of nonionic surfactants Pluronic F-127 and Brij S-100, which are similar in structure. Smaller diameter HiPCO nanotubes were better functionalized in dispersions of Triton X-405. The greater selectivity afforded by these poly(ethylene oxide) containing polymers is postulated to arise from electron donation provided by their ether oxygens. The ionic surfactant sodium dodecyl sulfate was found to display unique behavior in that semiconducting nanotubes were preferentially functionalized at natural pH, likely due charge localization interactions with the surfactant

Determination of glyphosate mono-isopropylamine salt in process samples using flow injection analysis with tris(2,2`-bipyridyl)ruthenium(II) chemiluminescence detection

The mono-isopropylamine salt of glyphosate was selectively determined directly in industrial and commercial formulations using flow injection analysis with tris(2,2&prime;-bipyridyl)ruthenium(II) chemiluminescence detection without the need for separation. Glyphosate and its mono-isopropylamine salt furnished detection limits of 7&times;10&minus;9 and 3.5&times;10&minus;10 M and relative standard deviations of 0.4% at 1&times;10&minus;7 M and 0.8% at 5&times;10&minus;8 M, respectively. The methodology is robust and reliable with samples subjected only to aqueous dilution prior to analysis.<br /

A screening test for heroin based on sequential injection analysis with dual-reagent chemiluminescence detection

A sequential injection analysis procedure with dual-reagent chemiluminescence detection was applied to the screening of street drug seizure samples for the presence of heroin. The chemiluminescence reagents (acidic potassium permanganate and tris(2,2&prime;-bipyridine)ruthenium(III)) were aspirated from either side of a sample aliquot that was sufficiently large to prevent interdispersion of the reagent zones, and therefore two different chemical reactions could be performed simultaneously at either end of the sample zone. The presence of heroin in seizure samples was indicated by a strong response with the tris(2,2&prime;-bipyridine)ruthenium(III) reagent and confirmed by a significant increase in the response with the permanganate reagent when the sample was treated with sodium hydroxide to hydrolyse the heroin to morphine. Nicomorphine (a morphine-derived pharmaceutical) was synthesised and tested under the same conditions. The responses with the permanganate reagent were similar to those for heroin, which supports the proposed chemical basis for the test. However, the responses with tris(2,2&prime;-bipyridine)ruthenium(III) were far lower for nicomorphine than heroin (approximately 5-fold for the samples that had not been hydrolysed).<br /

Comparison of ochre samples.

<p>NMDS ordination derived from a Bray-Curtis similarity matrix calculated from the square-root transformed abundance of 16S rRNA sequences matching the Greengenes database (13_08), order level.</p

Results of CAP analysis (using m = 1 principal coordinate axes, explaining 100% of the total variation) testing the hypothesis that elemental composition differ for each ochre sample.

<p>Results of CAP analysis (using m = 1 principal coordinate axes, explaining 100% of the total variation) testing the hypothesis that elemental composition differ for each ochre sample.</p