vidalia onion vinegarette for pesach

Question

I'm getting there! This dressing, made by vita: vegetable oil(canola and/or soybean), water, sugar distilled vinegar, vidalia onions, mustard(vinegar, water, mustard seed, salt, turmeric, paprika, spices, garlic powder) salat, dried onions, natural spices, xanthan gum, sodium.....(familiar chemicals)So i called the company and they told me that this product is "gluten free" so does that mean that the vinegar is okay? is mustard seed a problem( the lady was vague: she said it is probably most definitely a spice).