In this work, a novel carboxyl-functionalized organic–inorganic hybrid monolithic column (TMOS-co-CES) was prepared via one-pot co-condensation of carboxyethylsilanetriol sodium salt (CES) and tetramethoxysilane (TMOS). The TMOS-co-CES monolithic column was used as a needle-solid phase microextraction (SPME) matrix followed by using an inductively coupled plasma mass spectrometer (ICP-MS) for simultaneous speciation analysis of inorganic chromium and antimony. Various parameters of SPME operation and analytical performance were investigated systematically. Under the optimum conditions, the TMOS-co-CES column can selectively adsorb low-valent chromium (Cr(III)) and antimony (Sb(III)) without adsorbing high-valent species (Cr(VI) and Sb(V)) over a wide pH range (4.0–9.0). In the elution step, the captured Cr(III) and Sb(III) can be substantially completely eluted using 10% nitric acid (v/v) as the eluent. The TMOS-co-CES monolithic column based SPME protocol has the merits of facile preparation, low cost, selective adsorption and high adsorption capacity. In addition, the TMOS-co-CES column operates under milder elution conditions, offers higher recovery for antimony species, and is more compatible with the ICP-MS instrument, compared with a previously reported thiol-functionalized hybrid monolithic column taking speciation analysis of antimony as an example. Therefore, the developed TMOS-co-CES monolithic column is more suitable than the thiol-functionalized monolithic column for the speciation analysis of chromium and antimony in environmental waters.