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.

James VI of Scotland Letter, 1579

This letter authorizes William Hamilton of Portmollart to repair to Edinburgh notwithstanding the acts discharging the Hamiltons from being within six miles of the King’s person. James VI and James I (June 19, 1566 – March 27, 1625) was King of Scots as James VI from July 24th, 1567 and King of England and Ireland as James I from the union of the English and Scottish crowns on March 24, 1603 after the passing of Elizabeth I.

Opinion Regarding the Estate of S.D. Woodruff

An opinion regarding the estate of S.D. Woodruff. This is in regard to the liability of the estate to pay succession duties in Ontario upon certain American bonds and securities in the City of New York. This is a 6 page printed document prepared by Dewart, Young and Maw - February 7, 1905.

Estate of S.D. Woodruff in Account with H.H. Collier

The estate of S.D. Woodruff in account with H.H. Collier. This contains 1 1/2 printed pages listing expenses to be paid to Johnson Clench for copy of depositions, 1906-1907.

Almanac of S.D. Woodruff of St. Catharines

Almanac of S.D. Woodruff of St. Catharines (soft cover) containing records of items sold to various people, 1858-1866.

Canadian Bank of Commerce (vinyl cover), St. Catharines bank book of Welland D. Woodruff Esq.

Canadian Bank of Commerce (vinyl cover), St. Catharines bank book of Welland D. Woodruff Esq., 1915-1917.

List of inventory of goods in the dwelling of S.D. Woodruff of St. Catharines

List of inventory of goods (6 pages, handwritten) in the dwelling of S.D. Woodruff of St. Catharines. This list was examined by William Walker on Oct. 30, 1862 and compiled on Oct. 27, 1862.

List of inventory of goods in the dwelling of S. D. Woodruff, Ontario Street, St. Catharines

List of inventory (5 pages, handwritten) of goods in the dwelling of S. D. Woodruff, Ontario Street, St. Catharines, n.d.

List of abstracts (2 pages, handwritten) stating the cost of S.D. Woodruff dwelling and barns

List of abstracts (2 pages, handwritten) stating the cost of S.D. Woodruff dwelling and barns, January, 1878.

Memorandum of S.D. Woodruff’s property on Ontario Street

Memorandum (1 page, handwritten) of S.D. Woodruff’s property on Ontario Street, Jul. 25, 1901.

Letter to the Estate of W.D. Woodruff from S. Mitchell, secretary of the Lincoln Paper Mills Company

Letter to the Estate of W.D. Woodruff from S. Mitchell, secretary of the Lincoln Paper Mills Company (1 page, printed). This is a notice of the 43rd annual meeting of the shareholders of the Lincoln Paper Mills Company, Limited. This is accompanied by an envelope, Feb. 7, 1921.