Analyzers automated

Automated analyzers may be used for continuous monitoring of ambient poUutants and EPA has developed continuous procedures (23) as alternatives to the referenced methods. Eor source sampling, EPA has specified extractive sampling trains and analytical methods for poUutants such as SO2 and SO [7446-11-9] sulfuric acid [7664-93-9] mists, NO, mercury [7439-97-6], beryUium [7440-41-7], vinyl chloride, and VOCs (volatile organic compounds). Some EPA New Source Performance Standards requite continuous monitors on specified sources. 

Table 1. Clinical Tests Offered on Automated Analyzers ...

Ion-selective electrodes have been well received in the clinical laboratory and have allowed electrolyte panels to be routinely run on automated analyzers. The con-... 

Magnesium deficiency has been long recognized, but hypermagnesia also occurs (Anderson and Talcott 1994). Magnesium can be determined in fluids by FAAS, inductively coupled plasma atomic emission spectrometry (ICP-AES) and ICP-MS. In tissue Mg can be determined directly by solid sampling atomic absorption spectrometry (SS-AAS) (Herber 1994a). Both Ca and Mg in plasma/serum are routinely determined by photometry in automated analyzers. 

FitzGerald, S.P., Lamont, J.V., McConnell, R.I., and Benchikh, E.O. (2005) Development of a high-throughput automated analyzer using biochip array technology. Clin. Chem. 51(7), 1165-1176. 

Blood samples were centrifuged at 1000 x g for 20 min at 0-4°. Ionized calcium levels were immediately determined in serum and urine samples using a calcium ion-selective electrode (Ionetics, Inc., Costa Mesa, CA) urine volumes were recorded. The remaining serum and urine were aliquoted for various analyses and stored at -40°. Serum insulin was analysed by radioimmunoassay (Amersham Corp., Arlington Heights, IL). Serum levels of total calcium, phosphorus and creatinine as well as urine creatinine were determined by colorimetric procedures using an automated analyzer (Centrifichem, Baker Instruments Corp., Pleasantville, NY). Glomerular filtration rates (GFR) were calculated from serum and urine creatinine data GFR = urine creatinine/serum creatinine. 

Electrochemical ion-selective sensors (ISSs), including potentiometric ion-selective electrodes (ISEs) and potentiometric or amperometric gas-selective sensors (GSSs), attracted the interest of clinical chemistry because they offer fast, reliable, inexpensive analytical results in service-free automated analyzers. In this way, the electrochemical sensors satisfy the present demands of central hospital laboratories and peripheral point-of-care medical service points, such as bedside, emergency or first-contact healthcare centers. 

The most widely used sensor for chloride ions in clinical analyzers is based on an ion-exchanger, a quaternary alkylammonium chloride, dispersed in a plastic membrane. It is not an ideal sensor due to the interference of lipophilic anions (e.g., salicylates, bromides) and lip-ophylic cations (e.g., bacteriostatic agents, anesthetics) and a relatively poor selectivity towards hydrogen carbonates (bicarbonates). However, compared to charged anion- and neutral carrier-based membranes that have been tested, it is still the best-suited for automated analyzers. 

The total time for analysis—including sample preparation, separation, and detection—was 12.5 minutes for one sample, or 22 minutes for the sample and spiked sample. In tests on actual Hanford nuclear-waste samples, comparing results from the automated analyzer method to laboratory ICP-MS determinations, the analyzer method proved to be accurate in the determination of total "Tc. 

Methods 3 and 4 are colorimetric procedures based on reduction of nitrate to nitrite, followed by diazotization and then coupling to an azo dye. The analysis may be performed manually or by use of an automated analyzer. Method 2 is applicable in the range 10-5 to 10-1 MN03 . The colorimetric method 5 has been found to give inconsistent results. 

The glucose oxidase method (used in the dipsticks and by many automated analyzers) can show a false positive result in some species (e.g, dog, mouse) with high urinary ascorbate levels or in urine contaminated with hypochlorite (bleach) used as a disinfectant (Finco 1997 Loeb and Quimby 1999). 

The first automated analyzer was developed by Moore, Stein, Spackman, and Hamilton in the 1950s. Hydrolysates were separated on an ion-exchange column, followed by postcolumn reaction with ninhydrin. Although this system remains the standard method, its major drawback is low sensitivity. Several methods have since been developed offering high sensitivity and faster analyses without sacrificing reproducibility... 

E693 Woody, R.C., Turley, C.P. and Brewster, M.A. (1990). The use of serum electrolyte concentrations determined by automated analyzers to indirectly quantitate serum bromide concentration. Ther. Drug Monit. 12, 490-492. 

Routine cleaning and disinfection procedures are effective for decontaminating automated analyzers. Laboratory staff should disinfect analyzers after use following manufacturer recommendations or with a 5,000 parts per million solution (1 100 dilution) of sodium hypochlorite (1/4 cup of household bleach to 1 gallon of water). 

Surface areas of catalysts were determined by N2 adsorption using an ASAP 2000 analyzer from Micromeritics. Matrix and zeolite surface areas were calculated by the t-plot method accordingly to the ASTM-D-4365 standard test [11]. Zeolite unit cell size (UCS) was determined by X-Ray diffraction using a SIEMENS D-500 automated analyzer according to the ASTM-D-3942-80 standard [11]. 

In most situations, the specimen presented to an automated analyzer is serum or plasma. Many state-of-the-art analyzers (e.g., CX/LX series, ADVIA 1650 and 2400, Architect c-8000 series, MODULAR, DIMENSION) directly sample serum from primary collection tubes of various sizes. With such analyzers, the collecting tubes most frequently used contain a separator material that forms a barrier between supernatant and cells (see Chapter 2), Some analyzers also sample from a cup or tube that is filled with serum transferred from the original specimen tube. 

Evaporation of specimen from cups or tubes in the loading zone has caused analytical errors as great as 50% over 4 hours.Operationally, all cups or tubes containing solution for analysis should be covered until the time the specimen is to be analyzed. Many manufacturers of automated analyzers provide covers for individual cups or for part or the whole of the loading zone to reduce losses caused by evaporation. Cups may be covered by Parafilm or by caps that are placed over the cups and that have crosscuts to permit ready entry of a specimen probe. A type of antievap-orative cover that reduces evaporative losses to less than 0.1%/hr has been described. ... 

As its name implies, the chemical reaction phase occurs when aliquots of specimen and reagents are allowed to chemically react. Concerns related to this operation and the measurement of the reaction are addressed in the design of every automated analyzer. Design issues to be considered include (1) the vessel in which the reaction occurs and the cuvet in which the reaction is monitored, (2) the timing of the reaction(s), (3) the mixing and transport of reactants, and (4) the thermal conditioning of fluids. Separation of bound and unbound fractions is a fifth issue for immunoassay systems, as described in Chapter 9.. ... 

Computers and computer telecommunications are integral components of the entire analytical and reporting process and control the data input, operation, monitoring, and data reporting functions in automated analyzers. Also, workstations have been used to integrate the operation of one or more laboratory analyzers. Individual analyzers and/or their workstations are electronically interfaced with large central data repositories on laboratory information systems (LIS) and/or laboratory automation systems (LAS) (see Chapter 18). 

Figure I i-13 The Olympus OLA-2500 Decapper/Sorter/ Archiver/Aliquotter has a maximum sorting throughput of 800 tubes per hour and a typical aliquoting throughput of 600 tubes per hour. Olympus also has an OLA-4000 system, which includes centrifugation and can be integrated with up to two Olympus AU-series automated analyzers. (Courtesy Olympus America, Inc www.olympusamerica.com.)...

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