LOOMIS ENGINEERING & MANUFACTURING CO.
1
Courtesy Esso Research & Engineering Co. THE IDEAL PRESS FOR MAKING KBR PELLETS FOR INFRARED SPECTROSCOPE ANALYSIS * 20 Ton Capacity Hydraulic Press * Accurate alignment in op- eration * Guided moving platen * Sturdy 3 column construction * Even pressure distribution for uniformly dense pellets * Self-contained * Bench mounted * Hand operated * 9" χ 9" platen area * 22" max. vertical opening, adjustable A multi-purpose unit with quickly adjusted vertical opening, by handwheel, per- mits many different set-ups in minimum time. Used around the world for RESEARCH, CONTROL & TESTING. Available accessories include: Heat- ing and Cooling Platens; Temp. Con- trols; Auxiliary low pressure gauges; Fast air closing; Extruding units; Testing units, etc. Other capacities and sizes available. Write for Bulletin. LOOMIS ENGINEERING & MANUFACTURING CO. 133 So. 14th St., Newark 7, N . J . Circle No. 8 A on Readers' Service Card, page 73 A 8 A REPORT FOR ANALYSTS intermittently, and others only occasion- ally. The precision and accuracy required range from rough semiquanti- tative measurements to the highest degree of accuracy attainable. Quan- tities to be determined may be micro- grams or grams. To meet these diverse demands, the industrial hygiene analyst must be skilled in adapting and modify- ing existing methods, improvising equip- ment, and developing gadgets. The importance of obtaining a mean- ingful sample cannot be overempha- sized. This is particularly true in obtaining samples of air-borne materials, where the concentrations may be changing rapidly owing to operational procedures. Many types of sampling devices have been developed to obtain "grab" or "spot" samples as well as integrated or continuous samples. To prevent errors from such factors as insufficient sample, change in composi- tion, and interfering elements, close supervision of sampling is required. Analytical requirements are of three main types: (1) those required in toxicological studies, (2) those required in environmental investigations, and (3) those required to measure biological absorption and for diagnostic purposes. Toxicological Analysis In the investigation of the toxicity of a compound, it is necessary to have analytical procedures to measure and monitor the exposure conditions. It is also necessary to determine the com- pound in body tissues and fluids to establish the rate of absorption, distri- bution in the body, and rate of elimina- tion. Another requirement is the deter- mination of metabolites, which may provide basic information on the site and type of injury likely to be pro- duced and also may serve as a measure of exposure or as a diagnostic sign. Benzene may be taken as a typical example. At the start of an investiga- tion of the physiological effects of ben- zene, the analytical method used to determine chamber air concentrations and benzene in tissues was based on nitration of the benzene to m-dinitro- benzene and subsequent titration us- ing standard titanous chloride and standard ferric alum solutions. This method was cumbersome and required too large a sample for repeated blood analysis. Another method was developed, based on the aeration of the benzene from the blood, removal of car- bon dioxide, combustion of the benzene to carbon dioxide, absorption in barium hydroxide, and determination by elec- trical conductivity. This procedure was sufficiently sensitive to permit studying the rate of absorption and elimination of benzene from the blood, but entailed extreme care in technique and was time-consuming. Subse- quently, a colorimetric method was developed, based on the formation of a violet color by w-dinitrobenzene in the presence of butanone and strong sodium hydroxide solution. This method is sufficiently sensitive and rapid to pro- vide an excellent tool for the determina- tion of benzene in micro quantities in body tissues and fluids and may also be used for air analysis. During the course of this same study, the analysis of urine specimens showed that exposure to benzene caused a decrease 1 in the inorganic sulfates in the urine. Further studies in which ani- mals were exposed to carefully con- trolled benzene concentrations for var- ious exposure periods demonstrated a quantitative relationship between the decrease in inorganic sulfates in the urine and the magnitude of the exposure in terms of time and concentration. Thus, in this investigation, two new analytical techniques were developed for the determination of benzene in small concentrations and a new procedure was discovered for measuring benzene absorption which can be used in the prevention of injurious exposure to benzene in industry. Similar biological studies have resulted in the development of new or' modified procedures for determining many toxic materials in body tissues and fluids. The results obtained by utiliz- ing these analytical procedures have aided in the elucidation of biological action and provided diagnostic tools that are invaluable in the prevention of occupational disease. A few of the more common substances for which such data are available are lead, mercury, trichloroethylenc, methanol, and toluene. Since these tests usually require methods capable of determining amounts of the order of a few micrograms, application to other materials will depend on the development of suitable analytical pro- cedures. Environmental Analysis The requirements of methods for measuring environmental factors are diverse and complex, depending on the purpose for which the samples are taken. There are several reasons for industrial air sampling—for example. (1) to determine the major sources of dissemination of contaminants, (2) to appraise the performance of control equipment, and (3) to evaluate the environment in accordance with maxi- mum allowable concentrations or hygi- enic standards. In general, the methods used in ANALYTICAL CHEMISTRY
Transcript of LOOMIS ENGINEERING & MANUFACTURING CO.
Courtesy Esso Research & Engineering Co.
THE IDEAL PRESS FOR MAKING KBR
PELLETS FOR INFRARED SPECTROSCOPE
ANALYSIS * 20 Ton Capacity Hydraulic
Press
* Accurate alignment in operation
* Guided moving platen
* Sturdy 3 column construction
* Even pressure distribution for uniformly dense pellets
* Self-contained
* Bench mounted
* Hand operated
* 9" χ 9" platen area
* 22" max. vertical opening, adjustable
A multi-purpose unit with quickly a d j u s t e d vertical opening, by handwheel, permits many different set-ups in minimum time.
Used around the world for RESEARCH, CONTROL & TESTING.
Available accessories include: Heating and Cooling Platens; Temp. Controls; Auxiliary low pressure gauges; Fast air closing; Extruding units; Testing units, etc.
Other capacities and sizes available.
Write for Bulletin.
LOOMIS ENGINEERING & MANUFACTURING CO. 1 3 3 So. 1 4 t h St., N e w a r k 7, N . J .
Circle No. 8 A on Readers' Service Card, page 73 A
8 A
REPORT FOR ANALYSTS
intermittently, and others only occasionally. The precision and accuracy required range from rough semiquantitative measurements to the highest degree of accuracy attainable. Quantities to be determined may be micrograms or grams. To meet these diverse demands, the industrial hygiene analyst must be skilled in adapting and modifying existing methods, improvising equipment, and developing gadgets.
The importance of obtaining a meaningful sample cannot be overemphasized. This is particularly true in obtaining samples of air-borne materials, where the concentrations may be changing rapidly owing to operational procedures. Many types of sampling devices have been developed to obtain "grab" or "spot" samples as well as integrated or continuous samples. To prevent errors from such factors as insufficient sample, change in composition, and interfering elements, close supervision of sampling is required.
Analytical requirements are of three main types: (1) those required in toxicological studies, (2) those required in environmental investigations, and (3) those required to measure biological absorption and for diagnostic purposes.
Tox ico log ica l A n a l y s i s
In the investigation of the toxicity of a compound, it is necessary to have analytical procedures to measure and monitor the exposure conditions. It is also necessary to determine the compound in body tissues and fluids to establish the rate of absorption, distribution in the body, and rate of elimination. Another requirement is the determination of metabolites, which may provide basic information on the site and type of injury likely to be produced and also may serve as a measure of exposure or as a diagnostic sign.
Benzene may be taken as a typical example. At the start of an investigation of the physiological effects of benzene, the analytical method used to determine chamber air concentrations and benzene in tissues was based on nitration of the benzene to m-dinitro-benzene and subsequent titration using standard titanous chloride and standard ferric alum solutions. This method was cumbersome and required too large a sample for repeated blood analysis. Another method was developed, based on the aeration of the benzene from the blood, removal of carbon dioxide, combustion of the benzene to carbon dioxide, absorption in barium hydroxide, and determination by electrical conductivity. This procedure was sufficiently sensitive to permit studying the rate of absorption and
elimination of benzene from the blood, but entailed extreme care in technique and was time-consuming. Subsequently, a colorimetric method was developed, based on the formation of a violet color by w-dinitrobenzene in the presence of butanone and strong sodium hydroxide solution. This method is sufficiently sensitive and rapid to provide an excellent tool for the determination of benzene in micro quantities in body tissues and fluids and may also be used for air analysis.
During the course of this same study, the analysis of urine specimens showed that exposure to benzene caused a decrease1 in the inorganic sulfates in the urine. Further studies in which animals were exposed to carefully controlled benzene concentrations for various exposure periods demonstrated a quantitative relationship between the decrease in inorganic sulfates in the urine and the magnitude of the exposure in terms of time and concentration. Thus, in this investigation, two new analytical techniques were developed for the determination of benzene in small concentrations and a new procedure was discovered for measuring benzene absorption which can be used in the prevention of injurious exposure to benzene in industry.
Similar biological studies have resulted in the development of new or' modified procedures for determining many toxic materials in body tissues and fluids. The results obtained by utilizing these analytical procedures have aided in the elucidation of biological action and provided diagnostic tools that are invaluable in the prevention of occupational disease. A few of the more common substances for which such data are available are lead, mercury, trichloroethylenc, methanol, and toluene. Since these tests usually require methods capable of determining amounts of the order of a few micrograms, application to other materials will depend on the development of suitable analytical procedures.
Environmental Analysis
The requirements of methods for measuring environmental factors are diverse and complex, depending on the purpose for which the samples are taken. There are several reasons for industrial air sampling—for example. (1) to determine the major sources of dissemination of contaminants, (2) to appraise the performance of control equipment, and (3) to evaluate the environment in accordance with maximum allowable concentrations or hygienic standards.
In general, the methods used in
A N A L Y T I C A L C H E M I S T R Y
