Multiple sample sequential chemical analysis

A method for chromatographic separation of multiple analyte specimens using an analytical column containing a selective adsorbent media, through which column a carrier fluid flows, the method comprising:

• introducing a first analyte specimen into the analytical column at a first temperature;
• heating the analytical column to a second temperature to cause the first analyte specimen to partially travel into the column;
• cooling the analytical column to the first temperature;
• introducing a second analyte specimen into the analytical column;
• and
• heating the analytical column to a third temperature to cause analyte from the first analyte specimen and analyte from the second analyte specimen to concurrently and discretely travel through, and sequentially elute from, the analytical column.

A method of chromatographic separation prior to urinalysis to determine the concentration of methylmalonic acid in multiple urine specimens using gas chromatography, the method comprising:

• introducing a first urine specimen into a gas chromatograph column at an initial temperature;
• heating the gas chromatograph column to an intermediate temperature to cause methylmalonic acid from the first urine specimen to partially travel into the gas chromatograph column;
• cooling the gas chromatograph column to the initial temperature;
• introducing a second urine specimen into the gas chromatograph column;
• and
• heating the gas chromatograph column to a final temperature greater than the intermediate temperature, causing methylmalonic acid bands from the first and second urine specimens to concurrently and discretely travel through, and sequentially elute from, the gas chromatograph column.

An instrument for use in analysis of multiple analyte specimens contained in specimen reservoirs that are selectively sampled by operation of a specimen introduction means for introducing sampled specimens into a carrier fluid stream, the instrument comprising:

• a source of supply of a carrier fluid stream;
• a column containing selective adsorbent media and having an inlet and outlet, the carrier fluid stream flowing into the column inlet from the source of supply of the carrier fluid stream;
• specimen introduction means for selectively introducing samples of analyte specimens from specimen reservoirs into the carrier fluid stream at the column inlet;
• a heater for selective application of heat to the column;
• and
• control means for controlling the heater and the specimen introduction means for:
• automatically and sequentially introducing a first analyte specimen into the inlet of the column at an initial temperature;
• heating the column to an intermediate temperature to cause the first analyte specimen to partially travel into the column;
• allowing the column to cool to the initial temperature;
• introducing a second analyte specimen into the column;
• and heating the column to a final temperature greater than the intermediate temperature to cause analyte from the first analyte specimen and analyte from the second analyte specimen to concurrently and discretely travel through, and sequentially elute from, the outlet of the column.