In instrumental analysis, reference materials are gaining in importance with respect to the accuracy and precision of analytical measurements especially in terms of instrumental qualification and calibration. Merck Millipore supplies a range of first-class reference materials for all analytical methods under the trade name Certipur®. All Certipur® reference materials are traceable to national or international standards. Merck Millipore has accredited calibration laboratories that certify elemental standards, pH buffer and conductivity standards. And we are accredited as a Certified Reference Material producer according to ISO Guide 34 for our conductivity and ICP standards.