In the USP Pharmacopeial Forum 40(1), a "Stimuli to the Revision Process" article states that the responsible working group of the USP has conducted a review of the existing general chapters on spectroscopic methods. 

The goal of this review was to establish a uniform concept for all the spectroscopic methods and generate a common format. As a result, consistency in the overall approach and ease of use in the future should also be enabled for the user. 

The general chapters smaller than <1.000> show how to correctly use the methods ("suitability for use"), whereas the general chapters greater than <1.000> additionally provide so-called "best practices". Those chapters also include provisions on instrument qualification and on validation of spectroscopic methods. 

That's why some of these General USP Chapters have been once again published in this issue of the Pharmacopeial Forum:

<852> Atomic Absorption Spectroscopy
<853> Fluorescence Spectroscopy
<854> Mid-Infrared Spectroscopy
<857> Ultraviolet-Visible Spectroscopy

and as supplement to these chapters:

<1852> Atomic Absorption Spectroscopy - Theory and Practice
<1853> Fluorescence Spectroscopy - Theory and Practice
<1854> Mid-Infrared Spectroscopy - Theory and Practice

All these chapters are planned for the edition USP38/NF33 and will thus become effective in the coming year.

You will find more information on the USP Pharmacopeial Forum website.