Wet Chemical Analysis

In addition to modern analytical instrumentation, we offer many types of well worn wet chemical analyses that the pharmaceutical industry still widely performs and relies upon.  Often, modern instrumentation cannot ascertain results that many specific wet chemical tests provide.  Despite our investments in the most modern and up-to-date technology and methodologies, R.D. Laboratories is firmly committed to maintaining the equipment, knowledge and experienced staff to provide wet chemical analyses for our customers.  As part of this commitment to serving our customers’ needs, however varied they might be, we stock large inventories of reagents, test solutions, volumetric solutions, glassware and indicators.

Limit Test

Limit tests are frequently used to control specific impurities at predetermined levels.  Some of the limit tests we perform are aluminum, arsenic, chloride, sulfate, dimethylaniline, 4-epianhydrotetracycline, heavy metals, iron, lead, mercury, readily carbonizable substances, residue on ignition and selenium. We also perform numerous other monograph specific tests too numerous to list here.  Contact us to request information about your particular requirements.


Commonly used to test both raw materials and finished products, pH is defined as the negative log of the hydrogen ion concentration. Since pH affects parameters such as product stability, taste, degradation and even color, the specification is critical for some raw materials, as well as finished products.  R.D. Laboratories uses a properly calibrated pH meter with reference buffer solutions to perform testing of this sometimes overlooked but important characteristic.


Loss on Drying is a common requirement for raw materials. Not simply limited to water, it may also include impurities and some residual solvents. There are many techniques to measure LOD, all of which are monograph specific.

Thin Layer Chromatography

Thin Layer Chromatography is a versatile technique used to examine raw materials and finished products for impurities, identity and semi-quantitative analysis. Extremely valuable for certain specific types of determinations, R.D. Laboratories offers many types of substrates and developing solvents when performing this proven technique.


Identification testing uses wet chemical techniques to identify raw materials. These tests are sometimes used to distinguish between various salt forms.


Residue on Ignition (Sulphated Ash) measures the total non-specific content of inorganic impurities in an organic substance. This procedure is one of the most universally accepted ways to measure inorganic impurities in raw materials and is specified in all pharmaceutical compendia world-wide.


Viscosity testing techniques measure resistance to flow. This is defined as the shear stress divided by the rate of shear strain. We use the results from these tests to characterize both raw materials and finished products. The viscosity of a product may determine patient acceptance in the case of liquids, or indicate manufacturing suitability.

R.D. Laboratories uses Brookfield Viscometers (LVT and RVT) to satisfy USP, EP, JP, FCC, BP, ASTM, ACS, AOAC and customer specific methodologies. We provide for a wide variety of applications with extensive spindle set options.

We also offer a variety of capillary viscometers (Ubbelohde and Cannon-Fenske). For cellulose derived products we test with cellulose derivative capillary viscometers.

Additional Tests

R.D. Laboratories maintains the capability to perform wet chemical techniques too numerous to comprehensively list here.  Below are a few additional tests we perform.  If you do not see the procedure that meets your needs please contact us for more information.

  • Distillations
  • Titrations
  • Arsenic
  • Heavy Metals
  • Bulk Density
  • Melting range
  • Color testing
  • Sieve Analysis
  • Sulfur Dioxide
  • Carbonate Testing
  • Conductivity
  • Selenium
  • Container Performance Testing