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Sub-2-Micron Performance With a Conventional HPLC Instrument Using 2.7-Micron Fused Core Particles
Friday, March 20, 2009
Thomas L. Chester
Ultrahigh-performance liquid chromatography (UHPLC) utilizes sub-2-µm-diam stationary phase particles to provide improved performance over conventional HPLC. This can be realized either in a higher ... read more
Structural, Compositional, and Topographical Characterization of Polystyrene Films Using High-Resolution Dielectric Spectroscopy
Friday, April 02, 2010
Terry C. Chilcott Hans G.L. Coster Jeffrey L. Ellis
Thin polymeric films and surfaces provide novel electrochemical, thermal, mechanical, and/or biocompatible features at the nanoscale level in the development of adhesives, protective coatings, ... read more
Strategy for Improving HPLC Retention Time Prediction Accuracy Using Chromatography Simulation Software
Friday, October 01, 2010
Alexey Makarov Zhi Chen Fred Chan Rekha Bhashyam Rosario LoBrutto Raju Vegesna
The introduction of Quality by Design, a systematic approach to product and process design and development, has shifted the paradigm in HPLC methods development from a retrospective approach to a ... read more
Statistics in the Laboratory: Control Charts, Part 2
Wednesday, April 06, 2016
Stanley N. Deming
In the previous column (January/February 2016), we looked at the basic ideas behind control charts and saw how to construct a common X-bar and R chart. read more
Statistics in the Laboratory: Control Charts, Part 3
Thursday, May 26, 2016
Stanley N. Deming
In the previous two columns (January/February and April 2016), we looked at the basic ideas behind control charts, saw how to construct the common X-bar and R charts and discovered that only two ... read more
Statistics in the Laboratory: The Apparent Capability of an Industrial Process
Monday, January 16, 2017
Stanley N. Deming
It’s important to realize that information gets filtered and distorted by the inherent behavior of a measurement process. read more
Statistics in the Laboratory: Significant Digits and the Granularity of Data
Tuesday, June 05, 2018
Stanley N. Deming
A true story: one of my former graduate students called me and said, in effect, “Help. I know I’m a good analytical chemist, but my company is making me look like a perfect analytical chemist.” read more
Statistics in the Laboratory: Scedasticity
Friday, August 24, 2018
Stanley N. Deming
Homoscedastic and heteroscedastic—if nothing else, these are two good adjectives for word games. read more
Statistics in the Laboratory: Standard Deviation of the Mean
Friday, February 22, 2019
Stanley N. Deming
In the last column we discussed the use of pooling to get a better estimate of the standard deviation of the measurement method, essentially the standard deviation of the raw data. read more
Statistics in the Laboratory: Confidence Interval of the Mean
Wednesday, June 19, 2019
Stanley N. Deming
Estimated means are often used for making quantitative decisions (e.g., to decide if something meets specifications). read more
Statistics in Analytical Chemistry: Part 51–Internal Standards With Electrospray Mass Spectrometry
Thursday, February 14, 2013
Lynn Vanatta
In modern scientific laboratories, the electrospray mass spectrometer is being used extensively. The instrument is highly specific and for many applications is quite sensitive. read more
Statistics in Analytical Chemistry: Part 52—Corrections and Clarifications
Tuesday, April 09, 2013
Lynn Vanatta
As was stated at the end of Part 50, this current installment will be the last in the “Statistics in Analytical Chemistry” series. The mission of this article is to correct mistakes and clarify ... read more
Statistics in Analytical Chemistry: Part 50—Sampling Theory
Friday, November 23, 2012
Lynn Vanatta
Throughout this series of articles, the emphasis has been on calibration and recovery curves, which are necessary for the quantitative analysis of samples via analytical methods that involved simple ... read more
Statistics in Analytical Chemistry: Part 49—Relative Standard Deviations and Detection
Monday, August 27, 2012
David Coleman Lynn Vanatta
It is possible to associate a relative standard deviation or the more general relative measurement uncertainty (RSD and RMU, respectively) with a detection limit (DL). read more
Statistics in Analytical Chemistry: Part 47—Risky Calibration Practices
Monday, April 09, 2012
David Coleman Lynn Vanatta
In analytical chemistry, simple linear regression is often used to perform calibration or recovery activities. read more
Statistics in Analytical Chemistry: Part 48—Relative Standard Deviations (RSDs)
Tuesday, June 05, 2012
David Coleman Lynn Vanatta
The previous installment dealt with several regression practices that are risky in the world of calibration and recovery. read more
Statistics in Analytical Chemistry: Part 45—R² (Continued)
Tuesday, November 01, 2011
David Coleman Lynn Vanatta
In the previous installment (American Laboratory, Oct 2011), the terms that contribute to R2 were defined and a formula relating them was developed. read more
Statistics in Analytical Chemistry: Part 46—R² (Concluded)
Wednesday, February 08, 2012
David Coleman Lynn Vanatta
Over the course of the past two articles (Part 44,Oct 2011, and Part 45, Nov/Dec 2011), R2 has been defined, its components have been explained verbally and mathematically, and the statistic’s ... read more
Statistics in Analytical Chemistry: Part 44—R²
Saturday, October 01, 2011
David Coleman Lynn Vanatta
Imagine that a new method has been developed and now needs a calibration curve. read more
Statistics in Analytical Chemistry: Part 41—Blanks (Concluded)
Friday, January 28, 2011
David Coleman Lynn Vanatta
The previous article (American Laboratory, Oct 2010) left off with two interesting questions: 1) How does an analyst decide whether a positive response for a blank is low enough to be ignored? and 2) ... read more