Determination of low boron concentrations in nutrient solution
To study boron (B) deficiency and toxicity in plants in flowing solution culture, it is necessary to establish a wide range of solution B concentrations. The ability of inductively coupled plasma atomic emisson spectrophotometry (ICPAES) to determine solution B concentrations ranging from 0.15 μM to 925 μM was investigated. The reliablity of B concentration determination in nutrient solutions containing <10 μM B is poor. A technique, involving sorption by a B-specific resin (Amberlite-743), was established to concentrate the B present in low B nutrient solutions and to enable reliable measurement using ICPAES following elution from the resin. Acceptable, reproducible recoveries of B from low B solutions, containing known concentrations of B, were obtained using this technique. The technique enables the imposition, monitoring and maintenance of solution B concentrations well below the direct detection limits of ICPAES and colorimetric procedures. ei]L V Kochian
Measurement of boron concentration and isotope ratios in biological samples by inductivey coupled plasma mass spectrometry with direct injection nebulization
A method for the determination of boron in a variety of biological samples is described. Sample material is fused with sodium carbonate and boron is separated from matrix components by using Amberlite IRA-743 boron selective ion-exchange resin. Boron is eluted with 1% HNO3 and samples are introduced to an inductively coupled plasma mass spectrometer with a direct injection nebulizer. This nebulizer provides a fast sample cleanout of ca. 15 s. The 10B/11B ratio is determined with a relative standard deviation (RSD) of 0.4–1.5%, and the detection limit for boron is approximately 1 ng g−1 in these samples. Stable isotope dilution methodology for quantitation of boron shows that: (1) fusion of sample with sodium carbonate avoids volatilization of boron from samples; (2) approximately 80% of submicrogram amounts of boron from samples can be recovered from the resin with insignificant isotopic fractionation; (3) results for biological reference materials are in agreement with certified values; and (4) the boron concentration of pooled human blood plasma is 24 ± 4 μg l−1 (95% confidence interval).
Mutiny Echoes: India, Britons, and Charles Dickens's A Tale of Two Cities
This essay asks what, if any, import the Indian ““Mutiny”” of 1857 had on A Tale of Two Cities (1859), Charles Dickens�s fictionalized account of the French Revolution. Begun shortly after the Indian uprising started, Dickens�s historical novel appears studiously to avoid any mention of events on the Indian subcontinent, even though these events preoccupied and enraged the author. Few scholars have attended to the question of A Tale of Two Cities and the ““Mutiny,”” but when they have, scholars have looked for analogies between India and Dickens�s account of the French Revolution. In this essay, by contrast, I examine A Tale of Two Cities in a larger context——of Britons9 response to the Uprising, of Dickens9s short stories and essays in Household Words in the years before the ““Mutiny”” and immediately after, of Dickens9s disenchantment with aspects of British culture, and of his need to articulate a national identity grounded in action. I argue that the events in India were the match that ignited Dickens9s already established midcentury interests in national identity, nobility, and masculine heroism. I do not wish to suggest that A Tale of Two Cities is an Indian ““Mutiny”” novel, but rather that it is a novel about the ““Making of Britons,”” an important endeavor for an author who was intensely dissatisfied with the Britain that he saw around him.