US 12,158,454 B2Granted

Hybrid capillary/packed trap and method of use

AssigneeEntech Instruments Inc.

InventorDaniel B. Cardin

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Abstract

A hybrid trap including a replaceable open-tubular capillary trap followed by a packed trap is used to collect, preconcentrate, and recover a sample, such as VOCs and SVOCs found in air. The capillary stage prevents losses and carryover of the heavy fraction and can also collect the particles in air that contain the heavier SVOCs, also preventing them from reaching the packed stage. The packed stage traps lighter organic compounds that are not as prone to carryover due to channeling. The capillary and packed traps together provide quantitative recovery of compounds boiling from as low as −50° C. to as high as 600° C. The sample can be directly desorbed onto the GC column, which avoids losses and contamination caused by other approaches that thermally desorb samples through transfer lines and rotary valves more remote to the GC oven.

Claims24

Dependent claims

A field-portable trapping system, comprising:

a capillary stage, the capillary stage comprising an open tubular capillary column and an inlet end for receiving a sample including a gas sample, particulates, and one or more particulate-bound compounds, wherein an interior surface of the open tubular capillary column is coated by a sorbent, the sample is introduced to the trapping system directly through the capillary column;
a packed stage, the packed stage comprising a packed sorbent, the packed stage fluidly coupled to the capillary stage;
a body, the body comprising:
an interior cavity containing the packed sorbent;
and
a desorption port fluidly coupled to the interior cavity,
wherein at least a portion of the capillary stage is enclosed by the body;
and
a valve integrated with the body of the trapping system, wherein the valve is configured to fluidly couple an opening of the body to a pump when the pump is attached to the valve to collect the gas sample, the opening of the body fluidly coupled to the interior cavity of the body, the opening of the body being different from the desorption port of the body and the inlet end of the capillary column,
wherein:
the capillary stage is configured to retain and store the particulates and the one or more particulate-bound compounds of the sample collected by the trapping system without transferring the one or more particulates and the one or more particulate-bound compounds to the packed stage,
the packed stage is configured to retain one or more second compounds of the sample collected by the trapping system,
the one or more particulate-bound compounds are heavier than the one or more second compounds,
the pump causes a vacuum that draws one or more compounds from the sample from outside the trapping system directly to the capillary stage and through the capillary stage into the packed stage, and
the trapping system is field-portable and an analysis of the particulate-bound compounds and the one or more second compounds is performed using one or more portable chemical analysis devices.

12 more elements

A method for trapping a sample for chemical analysis using a field-portable trapping system comprising:

drawing the sample to the trapping system directly through a capillary stage using a pump, the sample comprising a gas sample, particulates, and one or more particulate-bound compounds, the trapping system comprising the capillary stage and a packed stage, wherein drawing the sample using the pump comprises:
drawing the particulates and the one or more particulate-bound compounds and one or more second compounds of the gas sample into the capillary stage of the trapping system, the capillary stage comprising an open tubular capillary column having an inlet end for receiving the sample, wherein an interior surface of the open tubular capillary column is coated by a sorbent;
retaining, using the capillary stage, the particulates and the one or more particulate-bound compounds collected by the trapping system and without transferring the particulates and the one or more particulate-bound compounds to the packed stage;
drawing the one or more second compounds into the packed stage of the trapping system, the packed stage comprising a packed sorbent;
and
trapping the one or more second compounds in the packed stage of the trapping system,
wherein:
the trapping system is field-portable and comprises a body, the body comprising:
an interior cavity containing the packed sorbent;
and
a desorption port fluidly coupled to the interior cavity,
wherein at least a portion of the capillary stage is enclosed by the body;
drawing the gas sample through the trapping system includes attaching the pump to a valve integrated with the body of the trapping system, wherein attaching the pump to the valve causes the valve to fluidly couple the pump to an opening of the body to collect the sample, the opening of the body fluidly coupled to the interior cavity of the body, the opening of the body being different from the desorption port of the body and the inlet end of the capillary column;
an analysis of the particulates and the one or more particulate-bound compounds and one or more second compounds is performed using one or more portable chemical analysis devices.

11 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/526,838Filed 30 Jul 2019 · us provisional application
Priority: 31 Jul 2018
Published: US 2020/0041469 A16 Feb 2020
Granted: 3 Dec 2024
Term ends: Not estimatedThe source records don’t support an estimate.

Classification16 codes

G01N 30/12
Preparation: by evaporation
G01N 30/6078
In open tubular form: capillaries
G01N 1/2214
Involving separation of sample components during sampling: by sorption
G01N 1/405
Concentrating samples: by adsorption or absorption