New Jersey Administrative Code
Title 7 - ENVIRONMENTAL PROTECTION
Chapter 18 - REGULATIONS GOVERNING THE CERTIFICATION OF LABORATORIES AND ENVIRONMENTAL MEASUREMENTS
Subchapter 5 - CHEMICAL TESTING
Section 7:18-5.4 - Requirements for general environmental laboratory practices

1. The laboratory shall use analytical reagent grade (AR) chemicals;

2. The laboratory shall examine stock and working standard solutions weekly and before each use for signs of decomposition, including, but not limited to, discoloration, formation of precipitates, and concentration change due to obvious evaporation. If the laboratory finds that a solution shows any such conditions, the laboratory shall discard the solution immediately;

3. The laboratory shall label all reagents and reagent solutions to indicate identity and, when applicable, titer, strength or concentration, recommended storage requirements, preparation date, expiration date, and any other pertinent information;

4. The laboratory shall immediately discard any reagent or reagent solution that is past its expiration date;

5. The laboratory shall use only standards of high purity for inorganic methods;

6. The laboratory shall mark all purchased chemicals, solutions, and standards with the date received by the laboratory and the date first opened by the laboratory;

7. If a DSAM requires the use of special purity solvents or reagents, a laboratory shall not perform an analysis pursuant to that DSAM using solvents or reagents of lesser purity;

8. The laboratory shall initially standardize prepared titrants. The laboratory shall restandardize such titrants at least quarterly. The laboratory shall restandardize purchased titrants at least quarterly. In standardizing or restandardizing a titrant, the laboratory shall use primary or secondary reagents as specified in the applicable DSAM;

9. The laboratory shall not use purchased standards or titrants unless they have a lot-specific certificate of analysis; and

10. The laboratory shall obtain or prepare calibration check standards and QC check samples from lots of materials different from those used to prepare calibration standards.