The determination of sampling and analytical errors in exploration geochemistry

1969 ◽  
Vol 64 (5) ◽  
pp. 568-569 ◽  
Author(s):  
Robert G. Garrett
Keyword(s):  
Exploration Geochemistry ◽  
Analytical Errors

Comparison of wet chemistry and near infrared reflectance measurements of carbon-fraction chemistry and nitrogen concentration of forest foliage

1991 ◽  
Vol 21 (11) ◽  
pp. 1689-1693 ◽  
Author(s):  
Toni M. McLellan ◽  
Mary E. Martin ◽  
John D. Aber ◽  
Jerry M. Melillo ◽  
Knute J. Nadelhoffer ◽  
...  
Keyword(s):  
Near Infrared ◽  
Nitrogen Concentration ◽  
Repeated Measurements ◽  
Infrared Reflectance ◽  
Near Infrared Reflectance ◽  
Carbon Fraction ◽  
Wet Chemistry ◽  
Methods Analytical ◽  
Analytical Errors

An interlaboratory comparison was designed to test the precision and relative accuracy of a method using near infrared spectroscopy for the determination of nitrogen, lignin, and cellulose concentrations in green and senescent foliage. A total of five laboratories were involved. Two methods of nitrogen analysis (Kjeldahl and CHN analysis) and two methods of carbon-fraction (lignin and cellulose) analysis were used. Equations for converting near infrared reflectance spectra into estimates of nitrogen and carbon-fraction concentrations are presented, along with estimates of relative bias between laboratories and methods. Analytical errors (variation among repeated measurements of the same sample) associated with each of the different methods are also presented. Results show that the near infrared reflectance method gives values that lie within the range of values generated by wet chemistry methods and so introduces no additional bias. Analytical errors are one-third to one-fifth those of wet chemistry methods for nitrogen concentration and one-fifth to one-eighth those of wet chemistry methods for lignin and cellulose concentration.

Device for More Economical Standby Operation of Continuous-Flow Analyzers

1975 ◽  
Vol 21 (11) ◽  
pp. 1667-1668
Author(s):  
Stephen C Wardlaw
Keyword(s):  
Continuous Flow ◽  
Consumption Rate ◽  
Flow System ◽  
Pumping Rate ◽  
Continuous Flow System ◽  
Reagent Consumption ◽  
Analytical Errors

Abstract To decrease the reagent-consumption rate of continuous-flow analyzers, I constructed a device that allows standby operation. The device, when actuated by switching off the sampler, decreases the effective pumping rate to less than 1/15 normal. The bubble pattern remains virtually undisturbed, and the system can be immediately restarted for emergency use. During five months of use in our laboratory with a Technicon platelet counter, the device has decreased reagent consumption by 60%, while allowing 24-hour-a-day operation. There have been no analytical errors traceable to the device, and no mechanical problems have arisen. I describe the use of the device in a continuous-flow system for determination of creatinine

Evaluation of determination of glucose in urine with some commercially available dipsticks and tablets.

1982 ◽  
Vol 28 (10) ◽  
pp. 2110-2115 ◽  
Author(s):  
Z L Bandi ◽  
J L Myers ◽  
D E Bee ◽  
G P James
Keyword(s):  
Method Comparison ◽  
Urine Samples ◽  
Comparison Of Methods ◽  
Urine Glucose ◽  
Glucose Determination ◽  
Upper Limit ◽  
Analytical Recovery ◽  
Precision And Accuracy ◽  
Analytical Errors

Abstract Four commercial products for urine glucose determination were evaluated and compared with a quantitative hexokinase procedure. We examined precision, sensitivity, and analytical recovery of glucose from glucose-supplemented urine samples and comparison of methods, using patients' samples. Only "Chemstrip uG" (Bio-Dynamics Inc.) could differentiate between 0.3 g/L (upper limit of normal) and 0.6 g/L urine glucose concentrations. "Tes-Tape" (Lilly) and "Diastix" (Ames) gave positive readings at 0.3 g/L; "Clinitest" (Ames) detected glucose only over 1 g/L. Analytical recovery of glucose was best, for all four products, between 1 and 2.5 g/L; Chemstrip uG was the most nearly accurate among the four. Between 5 and 20 g/L glucose concentrations, Tes-Tape, Diastix, and Clinitest tended to give falsely low results; the use of Chemstrip uG resulted in overestimates of concentration at 20 g of glucose per liter. Only Chemistrip uG and Clinitest (two-drop method) had linear ranges extending to 50 g/L; Chemstrip uG had better precision and accuracy at this concentration. Of the four products, Chemstrip uG had the lowest within-technologist and technologist-to-technologist random analytical errors. In method comparison on patients' samples, Chemstrip uG was significantly stronger in its association with the quantitative hexokinase method than was Diastix, Clinitest, or Tes-Tape.

Evaluation of Sampling and Analytical Errors in the Determination of Manganese in Soils

1998 ◽  
Vol 59 (3) ◽  
pp. 356-363 ◽  
Author(s):  
Deming Dong ◽  
Xianlei Zhu ◽  
Bin Yang ◽  
Miao Liu
Keyword(s):  
Analytical Errors

Matrix Effects in the Emission Spectrometric Analysis of Trace Metals in Biological Specimens

1974 ◽  
Vol 28 (1) ◽  
pp. 1-4 ◽  
Author(s):  
William Niedermeier ◽  
James H. Griggs ◽  
John Webb
Keyword(s):  
Trace Metals ◽  
Matrix Effects ◽  
Spectral Response ◽  
Spectrometric Analysis ◽  
Animal Tissues ◽  
Marked Influence ◽  
The Matrix ◽  
Analytical Errors

A study was made of the effect of metals that appear in animal tissues in the mg% range on the spectrochemical determination of certain trace metals in a NaCl matrix. The presence of as little as 1 mg% of iron, magnesium, calcium, potassium, or phosphorus had a marked influence on the spectral response of the trace metals (Cu, Fe, Al, Ba, Mn, Ni, Ca, Sn, Sr, Cr, Zn, Pb, Mo, and Cd) studied. Matrix effects in this medium did not appear to be concentration-dependent or additive. It was concluded that unless the matrix compositions of standard and specimen were closely matched, serious analytical errors would result.

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