Arsenic and germanium determination by hydride generation in the D.C. plasma optical emission spectrometer

Modifications to the commercial hydride generator, manufactured by Spectrametrics, resulted in improved operating procedure and enhancement of the arsenic and germanium signals. Experiments with arsenic(III) and arsenic(V) showed that identical reiults could be produced from both oxidation states. However, since arsenic(V) is reduced more slowly than arsenic(III), peak areas and not peak heights must be measured when the arsine is immediately stripped from the system (approximately 5 seconds reaction). When the reduction is allowed to proceed for 20 seconds before the arsine is stripped, peak heights may be used. For a 200 ng/mL solution, the relative standard deviation is 2.8% for As(III) and 3.8% for As(V). The detection limit for arsenic using the modified system is 0.50 ng/mL. Studies performed on As(V) standards show that the interferences from 1000 mg/L of nickel(II), cobalt(II), iron(III), copper(II), cadmium(II), and zinc(II) can be eliminated with the aid of 5 M Hel and 3% L-cystine. Conditions for the reduction of germanium to the corresponding hydride were investigated. The effect of different concentrations of HCl on the reduction of germanium to the covalent hydride in aqueous media by means of NaBH 4 solutions was assessed. Results show that the best response is accomplished at a pH of 1.7. The use of buffer solutions was similarly characterized. In both cases, results showed that the element is best reduced when the final pH of the solution after reaction is almost neutral. In addition, a more sensitive method, which includes the use of (NH4)2S208' has been developed. A 20% increase in the germanium signal is registered when compared to the signal achieved with Hel alone. Moreover, under these conditions, reduction of germanium could be accomplished, even when the solution's pH is neutral. For a 100 ng/mL germanium standard the rsd is 3%. The detection limit for germanium in 0.05 M Hel medium (pH 1.7) is 0.10 ng/mL and 0.09 ng/mL when ammonium persulphate is used in conjunction with Hel. Interferences from 1000 mg/L of iron(III), copper(II), cobalt(II), nickel(II), cadmium(II), lead(II), mercury(II), aluminum(III), tin(IV), arsenic(III), arsenic(V) and zinc(II) were studied and characterized. In this regard, the use of (NH4)ZS20S and Hel at a pH of 1.7 proved to be a successful mixture in the sbppression of the interferences caused by iron, copper, aluminum, tin, lead, and arsenic. The method was applied to the determination of germanium in cherts and iron ores. In addition, experiments with tin(IV) showed that a 15% increase in the tin signal can be accomplished in the presence of 1 mL of (NH4)2S20S 10% (m/V).

Arsenic speciation by ion-exchange chromatography with on- line determination by hydride generation: electronic modification of the D.C. plasma by photon counting

A method using L-cysteine for the determination of arsenous acid (As(III)), arsenic acid (As(V)), monomethylarsonic acid (MMAA), and dimethylarsinic acid (DMAA) by hydride generation was demonstrated. The instrument used was a d.c. plasma atomic emission spectrometer (OCP-AES). Complete recovery was reported for As(III), As(V), and DMAA while 86% recovery was reported for MMAA. Detection limits were determined, as arsenic for the species listed previously, to be 1.2, 0.8, 1.1, and 1.0 ngemL-l, respectively. Precision values, at 50 ngemL-1 arsenic concentration, were f.80/0, 2.50/0, 2.6% and 2.6% relative standard deviation, respectively. The L-cysteine reagent was compared directly with the conventional hydride generation technique which uses a potassium iodide-hydrochloric acid medium. Recoveries using L-cysteine when compared with the conventional method provided the following results: similar recoveries were obtained for As(III), slightly better recoveries were obtained for As(V) and MMAA, and significantly better recoveries for DMAA. In addition, tall and sharp peak shapes were observed for all four species when using L-cysteine. The arsenic speciation method involved separation by ion exchange .. high perfonnance liquid chromatography (HPLC) with on-line hydride generation using the L.. cysteine reagent and measurement byOCP-AES. Total analysis time per sample was 12 min while the time between the start of subsequent runs was approximately 20 min. A binary . gradient elution program, which incorporated the following two eluents: 0.01 and 0.5 mM tri.. sodium citrate both containing 5% methanol (v/v) and both at a pH of approximately 9, was used during the separation by HPLC. Recoveries of the four species which were measured as peak area, and were normalized against As(III), were 880/0, 290/0, and 40% for DMAA, MMAA and As(V), respectively. Resolution factors between adjacent analyte peaks of As(III) and DMAA was 1.1; DMAA and MMAA was 1.3; and MMAA and As(V) was 8.6. During the arsenic speciation study, signals from the d.c. plasma optical system were measured using a new photon-signal integrating device. The_new photon integrator developed and built in this laboratory was based on a previously published design which was further modified to reflect current available hardware. This photon integrator was interfaced to a personal computer through an AID convertor. The .photon integrator has adjustable threshold settings and an adjustable post-gain device.

Cabinet Card by C. Arthur, Photographer, St. Catharines [n.d.]

An unidentified young woman is featured in this black and white cabinet card by photographer C. Arthur, of St. Catharines, Ontario. The address of Mr. Arthur's studio is printed along the bottom of the photograph. This photograph was among the family memorabilia owned by Iris Sloman Bell of St. Catharines. The Sloman - Bell families include relatives who were former African American slaves who settled in Canada.Charles A. Arthur is listed as a photographer in St. Catharines from 1880 - 1883 and Charles P. Arthur (possibly a son?) was a photographer in the same city in 1898. Source: Phillips, Glen C. The Ontario photographers list (1851-1900). Sarnia: Iron Gate Publishing Co., 1990.

Photograph of Unidentified Woman by C. Arthur, Photographer, St. Catharines [n.d.]

An unidentified young woman is featured in this undated black and white studio photograph by C. Arthur, Photographer, of St. Catharines, Ontario. This small cabinet card photograph was in the possession of the Iris Sloman Bell family of St. Catharines. Relatives of the Sloman - Bell families include former African American slaves who settled in Canada.Two photographers by the name of Arthur are listed as working in St. Catharines, Ontario in the second half of the 19th century. Charles A. Arthur was a photographer from 1880 - 1883, while Charles P. Arthur (possibly a son?) is listed as a photographer in 1898. Source: Phillips, Glen C. The Ontario photographers list (1851-1900). Sarnia: Iron Gate Publishing Co., 1990.

Cabinet Card of Young Woman Photographed by N. C. Shorey, of Toronto [n.d.]

An unidentified African Canadian young woman is the subject of this cabinet card portrait photograph by N. C. Shorey, of Toronto, Ontario. The photo is undated but believed to be taken in the late 1890s. The photographer's stamp, with his name and address, appears in the gold lettering at the bottom of the card. The young woman in the photograph could possibly be a relative of the Sloman - Bell family, who resided in the London and St. Catharines areas. This cabinet card was in the possession of Iris Sloman Bell, of St. Catharines, Ontario. The Sloman - Bell family relatives are descended from former Black slaves from the United States.N. C. Shorey is listed as a photographer in Toronto, Ont. from 1892 - 1900. Source: Phillips, Glen C. The Ontario photographers list (1851-1900). Sarnia: Iron Gate Publishing Co., 1990. "Cabinet card photographs were first introduced in 1866. They were initially employed for landscapes rather than portraitures. Cabinet cards replaced Carte de visite photographs as the popular mode of photography. Cabinet cards became the standard for photographic portraits in 1870. Cabinet cards experienced their peak in popularity in the 1880's. Cabinet cards were still being produced in the United States until the early 1900's and continued to be produced in Europe even longer. The best way to describe a cabinet card is that it is a thin photograph that is mounted on a card that measures 4 1/4″ by 6 1/2″. Cabinet cards frequently have artistic logos and information on the bottom or the reverse of the card which advertised the photographer or the photography studio's services." Source: http://cabinetcardgallery.wordpress.com/category/cabinet-card-history/

Blueprint - 200 K.W. D.C. Vert. Type Gen. 125 V. 8 P. 600 R.P.M., B 89521, 10586, 2-R1-H21.6

A blueprint produced by Westinghouse Electric & MFG. Co. in Pittsburgh, Pennsylvanna. The blueprint is dated 19 August 1903 and is stamped "OBSOLETE".

Letter to S.D. Woodruff from John I. Mackenzie regarding 1 share of the Long Point Company transferred from Alexander McInnes and 2 shares transferred from E.C. Clark

Letter to S.D. Woodruff from John I. Mackenzie regarding 1 share of the Long Point Company transferred from Alexander McInnes and 2 shares transferred from E.C. Clark. The shares were transferred to John I Mackenzie, Sept. 6, 1870.

Letter to S.D. Woodruff from A.C. Leslie and Co., of Montreal

Letter to S.D. Woodruff from A.C. Leslie and Co., of Montreal saying that the glass that he wants is not usually kept in stock, June 5, 1875.

Letter to S.D. Woodruff from George C. Flint and Co.

Letter to S.D. Woodruff from George C. Flint and Co., Upholsterers and Furniture Manufacturers of New York regarding items such as mantle glass, cornices and fabrics. They have enclosed a handwritten price list with this letter (4 pages, handwritten), Sept. 13, 1876.

Letter to S.D. Woodruff from George C. Flint and Co.

Letter to S.D. Woodruff from George C. Flint and Co. stating that they will deliver furniture to his house, Sept. 13, 1876.

Letter to W.D. Woodruff from E.C. Wheeler Jr. of N.W. Harris and Co. Bankers of New York

Letter to W.D. Woodruff from E.C. Wheeler Jr. of N.W. Harris and Co. Bankers of New York (1 page, printed) saying that he is pleased that Mr. Woodruff has decided to take the $10,000 Dominion Powers at 90 and interest. They will expect Mr. Woodruff in a few days, Dec. 10, 1907.

Letter to W.D. Woodruff from E.C. Wheeler Jr. of N.W. Harris and Co. Bankers of New York

Letter to W.D. Woodruff from E.C. Wheeler Jr. of N.W. Harris and Co. Bankers of New York (1 page, printed) regarding taking on some more of the Chicago, Rock Island and Pacific Railway bonds, Jan. 15, 1909.