Effectiveness of oak leaves as bioindicators of environmental pollution

The purpose of this study was to use instrumental neutron activation analysis (INAA) to investigate the effectiveness of oak tree leaves as indicators of atmospheric pollution. Leaves were sampled from several different cities in southwestern Ontario, Canada and tested for 16 different trace elements (U, Dy, Ba, Ti, Sr, I, Br, Mg, Cu, Na, V, K, Al, Mn, Cl and Ca). The results show promise for the use of oak leaves as multielemental environmental monitors due to their apparent ability to reflect the overall pollution levels of the vicinity in which they grow. Oak leaves were found to be superior to both birch and maple leaves for monitoring most of the elements studied.     

Instrumental neutron activation analysis of Obsidian rock

An instrumental neutron activation analysis technique has been developed for the simultaneous determination of up to 30 elements including major, minor and trace elements in Obsidian Rock (a proposed NBS-SRM-278). INAA method involves both short and long irradiations followed by gamma-ray activity measurement with a Ge(Li) detector. The accuracy of the procedure has been checked by analyzing IAEA Reference Materials.     

Microdetermination of bromate ions with antipyrine

Summary A spectrophotometric method for the micro-determination of bromate ions has been described. A red colored complex is obtained when 3 ml of 5% antipyrine, 3 ml of 60% perchloric acid and 1 ml of 0.1M sodium nitrite solution are added in a solution containing bromate ions. The maximum absorbance occurs at 525 nm. Beer's law is obeyed for solutions containing 25.0–140.0/ml of bromate ions. Sensitivity has been found to be 0.029g BrO₃ ^–/cm² for logI ₀/I=0.04 with a molar absorptivity of 2·10³ moles^–1, cm^–1. liter. As(III), Ce(IV), Fe(III), CrO₄ ^2–, Cr₂O₇ ^2–, and Cl^– interfere in the determination.

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Zusammenfassung Eine spektrophotometrische Methode zur Mikrobestimmung von Bromationen wurde beschrieben. Nach dem Zusatz von 3 ml 5%iger Antipyrinlösung, 3 ml 60% iger Perchlorsäure und lml 0,1 ·m Natriumnitrit zu einer bromathaltigen Lösung erhält man eine rot gefärbte Komplexverbindung. Deren Absorptionsmaximum liegt bei 525 nm. Lösungen mit 25,0 bis 140,0g Bromat/ml entsprechen dem Beerschen Gesetz. Die Empfindlichkeit der Reaktion beträgt 0,029g BrO₃ ^–/cm₂ für logI ₀/I=0,04 mit einer molaren Absorption von 2 · 10³ m^–1 · cm^–1 · 1. As(III), Ce(IV), Fe(III), CrO₄ ^2–, Cr²O₇ ^2– und Cl^– stören die Bestimmung.

     

Extraction of molybdenum(VI) by 4-(5-nonyl)pyridine in benzene from aqueous mineral acid solutions containing thiocyanate ions

Extraction of Mo(VI) by 4-(5-nonyl)pyridine (NPy) in benzene from mineral acid solutions containing thiocyanate ions has been investigated at room temperature (23±2°C). From mineral acid (HCl, HNO₃, and H₂SO₄) solutions alone Mo(VI) is not extracted quantitatively while the presence of small amounts of KSCN in the system augments the extraction by a large factor. Stoichiometric studies indicate that ion-pair type complexes (NPyH)₂·[MoO₂(SCN)₄] are responsible for the extraction. Separation factors determined at fixed extraction conditions (0.1M Npy/C₆H₆–0.1M acid +0.2M KSCN) reveal that Ag(I), Cu(II), Co(II), Zn(II), Hg(II) and U(VI) are co-extracted while a clean separation from alkali metals, alkaline earths and some transition metals like Ln(III), Zr(IV), Hf(IV), Cr(III), Cr(VI) and Ir(III) is possible. Some of the complexing anions like oxalate, citrate, acetate, thiosulfate or ascorbate do not affect the degree of extraction of Mo(VI) allowing it to be recovered from diverse matrices.     

Paper chromatography of metal ions in solvents containing methylamine

Summary The effect of methylamine and methylamine hydrochloride has been systematically investigated in the paper chromatography of various metal ions. It has been found that methylamine hydrochloride like EDTA helps in preventing tailing. A new separation of Fe, Mn, Ni, and Co has been developed. The R_f-values are 0.97, 0.49, 0.08, 0.79 respectively and the solvent system used is ethylacetoacetate/methylamine hydrochloride/conc. hydrochloric acid (2027). The values are equally spaced, the spots are compact and the separation is probably the best yet recorded.

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Zusammenfassung Es wird über eine systematische Untersuchung des Einflusses von Methylamin und Methylaminhydrochlorid bei der Papierchromatographie verschiedener Metallionen berichtet. Dabei ergab sich, da\ Methylaminhydrochlorid Ähnlich wie ÄDTA zur Verhinderung der Schwanzbildung benutzt werden kann. Zur Trennung von Fe, Mn, Ni und Co wird ein Lösungsmittel aus Acetessigester, Methylaminhydrochlorid und konz. SalzsÄure (2027) empfohlen (R_f-Werte: 0,97, 0,49, 0,08 bzw. 0,79), mit dem sehr gute Ergebnisse erzielt wurden.

     

Selective role of oxidants in the presence of cation-exchange resins in Na(+)-form for the detection and differentiation of acidic, basic and neutral amino-acids

A test for detection and differentiation of acidic, basic and neutral amino-acids is based on use of a sulphonic acid cation-exchange resin in Na(+)-form, in the presence of various oxidants (permanganate, dichromate, chromate, iodate, peroxide) and final detection with Nessler's reagent.     

Identification of seventeen vitamins by circular thin-layer chromatography

Summary A method is described for separation and identification of 17 vitamins by circular-thin layer chromatography. The method is simple and convenient; separation is complete within 2 minutes. The method is very sensitive and is specially suitable for routine identification when quick results are required.

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Zusammenfassung Ein einfaches Verfahren zur Trennung und Identifizierung von 17 Vitaminen durch Dünnschicht-Ring-Chromatographie wird angegeben. Innerhalb von 2 Minuten ist die Trennung vollzogen. Die Methode ist sehr empfindlich und für Routinezwecke besonders geeignet, wenn die Ergebnisse rasch benötigt werden.

     

Quantum eraser for three-slit interference

It is well known that in a two-slit interference experiment, if the information, on which of the two paths the particle followed, is stored in a quantum path detector, the interference is destroyed. However, in a set-up where this path information is ‘erased’, the interference can reappear. Such a set-up is known as a quantum eraser. A generalization of quantum eraser to a ‘three-slit’ interference is theoretically analysed. It is shown that three complementary interference patterns can arise out of the quantum erasing process.