The present invention relates generally to a novel method using HPLC and fluorescence detection of free PEG-mal in PEGylated proteins and PEG-mal raw materials by adding a fluorescent label to the free PEG-mal.

A personal-sized, portable explosive detection field test kit (ETK) and related methods of use. Embodiments of the disclosed ETK include a case having a closing system featuring three levels of closure which retain the case cover securely in a closed position until ready for use, while being easily opened when necessary. The ETK instructions are permanently attached to the case to prevent loss. The case includes retention features which retain the kit components until needed and protects them against loss or damage. The ETK includes one or more test tubes that are color coded and include abbreviated instructions.

The present invention provides a compound of formula I:

##STR00001##

wherein X.sup., R.sup.1, and R.sup.2 are as defined herein, and compositions thereof.